The flow restrictor is located in the yellow drain line of your Black and White reverse osmosis unit. The number indicates its output in mg/L.
The flow restrictor’s function is to regulate the flow of brine, or reject water, leaving the RO membrane housing. It is an essential part of the reverse osmosis process. If the restrictor allows too much water to exit the housing, the RO unit will not produce enough water; too little flow through the restrictor will damage the membrane and lower the quality of the water produced.
The number printed on the restrictor indicates its approximate output in mg/L. Actual output can vary and is influenced by such factors as inlet water pressure, water temperature, and general water quality.
To test the restrictor, turn off the storage tank valve and open and leave open the ledge faucet. When a small stream or fast drip of water is coming from the faucet, it means the unit is making water. Remove the drain line from the undersink drain saddle. There should be a small stream flowing from the drain tube. Catch the stream in a measuring cup that measures milliliters and time for one minute. The output should be more or less the same as the number printed on the restrictor. If the actual output is in the ballpark of the number printed on the restrictor, all is well. If it’s way off, the restrictor should be replaced.
Be sure to replace the restrictor with the size that matches your membrane. See our Reverse Osmosis Parts page for replacement restrictors. Make sure you get the restrictor that matches you membrane size, as explained on the page.
There is Growing Sentiment in the UK That Companies that Produce Wet Wipes Should Pay for Their Removal from Wastewater
Water companies claim that wet wipes, which shed microplastic particles and also build up into major blockages, are the main cause of sewage pollution. John Penicud, Southern Water’s managing director for wastewater, said recently that “the majority of wastewater pollutants are caused by wet wipes, fats, oils and grease being flushed down toilets and sinks.” He called for wet wipes to be banned.
To deal with wet wipes, the EU is introducing quaternary treatment, a more advanced method than that used in the UK. This has powerful filters that remove these trace chemicals from the water supply, but is expensive, so the bloc is looking at making the producers of these chemicals pay a levy that would then be used to create these treatment plants. Producers would be required to cover at least 80% of the costs associated with the sewage treatment upgrades necessary for removing these substances from wastewater. Guardian.
Lead Service Lines in Connecticut
New data obtained by The Connecticut Mirror shows there could be as many as 8,000 lead service lines still in use in public water systems throughout the state — though that number is likely to change as water utilities continue to inspect basements, unearth pipes and comb through century-old records to verify how much lead remains in the ground.
The data provides the first public look at how many people in Connecticut could be consuming water that travels through lead lines. And it highlights how that aging infrastructure is not distributed equally throughout the state. CT Mirror.
The Central Texas Flood
By far the month’s most intense water story was the 4th of July Central Texas flood that killed almost 200 people, many of them children, and instigated speculation about the Trump administration’s failure to meet its obligation in supporting weather science and protection against climate change. Here’s an example of opinion:
The deadly Texas floods could signal a new normal in the US, as Donald Trump and his allies dismantle crucial federal agencies that help states prepare and respond to extreme weather and other hazards, experts warn.
More than 100 are dead and dozens more remain missing after flash floods in the parched area known as the Texas Hill Country swept away entire holiday camps and homes, in what appears to have been another unremarkable storm that stalled before dumping huge quantities of rain over a short period of time, a phenomenon that has become increasingly common as the planet warms.
There is mounting concern that the chaos and cuts instigated by Trump and Elon Musk at the National Weather Service (NWS) and Federal Emergency Management Agency (Fema) may have contributed to the death toll. The Guardian.
Historic Drought Hits England
LONDON (Reuters) -Britain’s Thames Water announced a temporary “hosepipe ban” on Monday, aimed at cutting water usage across large parts of southern England, following the country’s driest and warmest spring in over a century.
Thames Water, Britain’s biggest water supplier which has 16 million customers, said the ban would take effect on July 22, and apply to households across several counties including Oxfordshire, Wiltshire, Gloucestershire and Berkshire, but not in London.
Under the ban, customers are prohibited from using hosepipes for activities such as washing cars, watering gardens or allotments, filling paddling or swimming pools, and cleaning windows.
Other water suppliers in England have also introduced bans this month, with Yorkshire Water and South East Water both announcing temporary restrictions last week.
Millions Warned to Stay Out of Lakes Because of Weather Conditions
More than 13 million people along lake shorelines in the U.S. were advised to “stay out of the water” on Thursday as weather conditions created a dangerous environment in the water for beachgoers. The Great Lakes consistently rank as a premier recreation destination in the U.S., especially during summer. Despite water temperatures that remain cold early in the season, recreational swimmers frequent the region’s beaches.
The beach hazards statement comes as the Great Lakes Surf Rescue Project has reported 38 Great Lakes drownings this year. Most drownings occur at Lake Michigan, but water-related injuries and deaths can also occur at the other Great Lakes.
Swimming Pool Recall
More than 5.2 million aboveground swimming pools sold across the U.S. and Canada over the last two decades are being recalled after nine drowning deaths were reported.
The recall covers a range of Bestway, Intex Recreation and Polygroup pools that were sold by major retailers as far back as 2002. According to Monday notices published by the U.S. Consumer Product Safety Commission and Health Canada, these pools have compression straps running along the outside of the product — which “may create a foothold” for small children and allow them to access the water unattended. MSN
Awareness of PFAS Contamination Grows
Over 73 million people in the US are being exposed to toxic PFAS chemicals in their tap water, according to an analysis of data from a US Environmental Protection Agency (EPA) water monitoring program. (Read the rest of the story here.)
Flooding A Serious Threat in Ohio Because of Ageing Dams
Dams in parts of the country are now in serious need of repair. Their failure puts new areas at risk of serious flooding. The Guardian explains:
Through the Inflation Reduction Act, the Biden administration had made investing in America’s ageing infrastructure over the course of many years a priority, with $10bn dedicated to flooding mitigation and drought relief. An additional $3bn was allocated in 2021 through the Infrastructure Investment and Jobs Act for dam safety, removal and related upgrades.
Since Donald Trump entered the White House in January, the administration has vowed to roll back much of those investments. Hundreds of dam safety and other staffers working at dams in 17 western states have been laid off in recent months. Before the 4 July flood disaster in Texas, the Trump administration had pledged to close the Federal Emergency Management Agency (Fema). With more than 92,000 dams across the country, the Society of Civil Engineers estimates the cost of repairing the country’s non-federal dams at $165bn. The Guardian
Iran Is Considering Moving Its Capital Because of Severe Water Shortage
At least 20 of Iran’s 31 provinces are now suffering a water crisis. Iranian President Masoud Pezeshkian is reportedly not ruling out relocating the capital city of Tehran over the severe water shortage that has gripped the country, Der Spiegel reported on Thursday, citing Iranian media. Critics of the regime blame the water crisis on the government’s failure to address climate change. Jerusalem Post
Several died in flash flooding events in New Mexico during July. New York Times.
2025 Is Now Recognized as the Year of Flash Flooding in America
The U.S. has seen devastating flash floods throughout its history, but rising global temperatures today are increasing the risk of flooding.
As ocean and air temperatures rise, atmospheric water vapor increases. Higher ocean temperatures can produce more atmospheric water vapor through evaporation, and a warmer atmosphere can hold more moisture, fueling downpours. In some high-risk areas, meteorologists, aware of the risks, say they are becoming more proactive about warning communities.
Currently, evidence shows atmospheric water vapor is increasing in the overall global climate system as temperatures rise. The Conversation.
“One of the worst marine disasters in living memory”
South Australia’s toxic algal bloom is twice the size of the Australian Capital Territory, has killed 13,800 animals and is filling even the experts with dread. Tory Shepherd and Lisa Cox, as well as our video team, explored the causes and impact of “one of the worst marine disasters in living memory”. Full story from The Guardian.
Chicago Fails To Warn Most Residents About Lead In Water
By Riley Kleemeier
Gazette Introductory Note: This article underlines how impractical it is to believe that that regulation will assure water that’s safe to drink from the tap. In this case, a point of use drinking water filter that removes lead makes a lot more sense than waiting for the city to replace lead pipes.
In Chicago, a federal drinking water rule required officials to notify 900,000 properties that their drinking water is at risk of lead contamination. But as of early July, only 7% of the people on that list had been warned that their water may be putting them at risk for serious health issues.
Of the approximately 490,000 service lines in Chicago, around 412,000 are at least partly made of lead, making the city the most reliant on lead pipes in the nation.Federal law requires water systems to inform residents on a yearly basis about lead pipes until they are completely replaced, but eight months have gone by without any notification.Chicago has attempted to put tools in place to notify residents if their property is likely to have a lead service line, such as an online lookup tool or free lead test kits. But the program is currently backlogged, and some residents have been waiting for months to receive results.
Chicago isn’t the only city tasked with notifying a large number of residents about lead service lines — but other big cities have been able to meet the moment. In Milwaukee, for example, 100,000 notices were sent in a single day, while Chicago is straining to send 3,000 in one week.Replacing lead service lines is no easy task, especially in a city like Chicago that requires hundreds of thousands of replacements — while also requiring permission from homeowners to do so in some cases.The Biden-Harris Administration issued the final rule requiring the replacement of lead pipes within a decade in October of 2024.
Chicago’s current plan puts it 30 years behind that deadline. This delay will prolong the exposure of toxic lead in drinking water to children and adults in Chicago.“We not only need them to step up and catch up really quickly, but we also need the state of Illinois and EPA to use their powers to hold them accountable for this blatant lack of compliance with the law,” Suzanne Novak, a senior attorney for the nonprofit Earthjustice, said of city officials.For now, many Chicago residents will continue to wait on information regarding next steps, and continue to worry about the safety of their drinking water.
Almost 40% of glaciers in existence today are already doomed to melt due to climate-heating emissions from fossil fuels, a study has found. The loss will soar to 75% if global heating reaches the 2.7C rise for which the world is on track. The massive loss of glaciers would push up sea levels, endangering millions of people and driving mass migration. The Guardian.
Crypto Outbreak in Devon
BBC reported that in Devon a cryptosporidium outbreak, which contaminated the local water supply and lead to hospitalizations and more than 100 reported cases of illness, caused significant financial loss to the water supplier. BBC.
De Not Eat Warnings for Fish in Michigan
Amid evidence that PFAS is far more dangerous than previously thought, state officials have revised statewide guidelines for eating contaminated fish.
Michigan health officials have dramatically reduced the amount of PFAS-tainted fish they consider safe to eat, tripling the number of water bodies where anglers are warned against eating their catch.
Ninety-eight water bodies are now subject to “do not eat” advisories because fish are contaminated with the so-called “forever chemicals,” up from 33 last year. Hundreds more advisories suggest that Michiganders limit meals of certain fish species to anywhere from 16 servings a month to six a year.
Officials with the Michigan Department of Health and Human Services announced the change Monday while publishing the annual Eat Safe Fish Guide, a document that identifies waterways where fish are contaminated with unsafe levels of toxic chemicals. Bridge Michigan
Diesel Spill in Baltimore
A leak of some 2000 gallons of diesel at Johns Hopkins Hospital in East Baltimore traveled through storm drains for more than a mile to the harbor. The impact on drinking water quality is still unclear. Newsweek
Salmonella Traced to Cucumbers Grown in Contaminated Irrigation Water
A salmonella outbreak tore through the country last spring and summer, infecting more than 550 people and sending 155 to the hospital.
The likely culprit wasn’t raw eggs or undercooked chicken but an innocuous salad staple: cucumbers.
One year later, cucumbers are once again making people sick — and federal officials say that one of the same Florida farms is once again involved. Forty-five people in 18 states recently contracted salmonella in an outbreak linked to cucumbers from Bedner Growers in Palm Beach County, setting off a widespread recall that has affected everything from California rolls sold at Target to banh mi sandwiches served at a North Carolina high school.
The Food and Drug Administration has yet to explain how the cucumbers linked to the current outbreak became contaminated; the investigation is ongoing. But last year, the agency found that Bedner Growers had used untreated canal water for irrigation — and that the water was contaminated with one of the salmonella strains that had made people sick.
Cucumbers and other fresh produce may be a surprising source of salmonella, which can cause diarrhea, stomach cramps and fever, as well as more serious health problems that can turn fatal. Heat from cooking can kill the bacteria, but fruits and vegetables that are eaten raw, like cucumbers, can be unsafe once they are contaminated. That means it’s particularly important to protect fresh produce from pathogens lurking in water used for irrigation or washing. NBC News.
Contaminated Water Blamed for Elephants’ Death
The unexplained deaths of hundreds of elephants near watering holes across the Okavango delta in May 2020 alarmed conservationists. Nearly five years later, scientists finally published a paper indicating what they believe to be the reason behind the deaths: toxic water caused by an algal bloom. The Guardian
National Hydration Day
National Hydration Day was June 23. As far as we can determine, not a single business or government office anywhere closed to honor the holiday.
In Ottawa County Ohio, a water treatment employee was found dead inside a water tank, prompting a boil advisory in multiple areas in the state.
According to WTOL, citing a report from the Ottawa County Sheriff’s Office, authorities responded to the Ottawa County Regional Water Treatment Plant on Monday and discovered a night shift employee floating face down in a tank filled with water. WKRC – TV
Expectant Mothers Advised to Drink Filtered Water
Pregnant women have been advised to use water filters by experts who spoke to Newsweek after a study found levels of arsenic in water systems considered safe are impacting birth outcomes.
A national study led by researchers at Columbia University evaluated risks from 13,998 pregnancies across 35 cohort sites participating in the National Institutes of Health’s Environmental influences on Child Health Outcomes (ECHO) program, and published its findings on the medical journal site JAMA Network last week.
The researchers discovered that prenatal exposure to arsenic was associated with a higher likelihood of babies being born preterm with lower birth weights, factors that they said are important “predictors of infant mortality and morbidity across the life span.”
This was the case even at the level of exposure the Environmental Protection Agency (EPA) currently deems safe, 10 micrograms per liter, a regulation that was established in 2001 and has not been changed since. Newsweek. Full article.
1. Remove well cover. Pour the required amount of bleach into the well. See the list below.
2. Run ALL faucets in the house, one at a time, until you smell the chlorine at the faucet. This ensures that the whole system will be disinfected
3. Connect a garden hose to an outside tap or an indoor tap with the correct thread fitting. Put the other end of the hose into the well, turn on the faucet, and from time to time move the hose so that the chlorinated water bathes the sidewalls of the well casing. Do this for at least six hours. Turn off tap and remove the hose from the well.
4. Replace the well cover
5. DON’T USE THE WATER for at least twelve hours. Forty-eight hours in optimal.
6. Run the water to waste but NOT INTO THE SEPTIC SYSTEM for several hours, or until the chlorine taste is dilute enough to be unobjectionable. The best way to run the water to waste is to use the garden hose mentioned above (item 3). Direct the hose into an area where the chlorinated water will not cause environmental damage or affect the water supply of others. For a typical well, this may take 3-4 hours. NOTE: To avoid pump overheating and possible damage, turn off the water when flow is at a trickle and wait at least 15 minutes before turning on the pump again
7. After a week of use, retest for bacteria.
8. In some cases, one chlorination treatment WILL NOT be sufficient. Repeat disinfection procedures as needed.
Well Depth
Amount of Liquid Household Bleach
Up to 150 ft — One Quart
151-300 ft.–Two Quarts
>300 ft– One gallon and 1 cup of crushed swimming pool tablets.
The exceptional value of a good water test and how to understand what it means
For some years we been offering high quality water tests to our customers provided by National Testing Laboratories of Cleveland. General information and pricing for these excellent tests can be found here on our website.
The lab offers a comprehensive test (Watercheck) as well as specific city water and well water versions. A number of individual analytes not included on the standard tests (iron bacteria, for instance) can also be added if needed.
How It Works
The test is ordered from our website. Upon receipt of the order, we send you a test kit. You then take samples of your water, as directed in the kit, and overnight the samples to the NTL laboratory in Cleveland. The lab reports the results to you in an easy-to-understand format and also sends us (Pure Water Products) a copy of the results so we can help with interpretation and recommendations for treatment if you ask us.
The lab also makes available valuable online information to help with understanding the test result. Here are a couple of valuable reference guides provided.
A comprehensive chart giving detailed information about water contaminants such as commons sources of the contaminant in drinking water, the allowable amounts, the treatments required for removal with very helpful color coding for classification of the contaminant.
Which drink is best for hydration? Hint: It isn’t water
by Lisa Drayer
When you’re thirsty and in need of a drink, which beverages are best at keeping you hydrated?Sure, you can always reach for a glass of water — but plain H20 isn’t the most hydrating beverage around, according to a study from Scotland’s St. Andrews University that compared the hydration responses of several different drinks.The researchers found that while water — both still and sparkling — does a pretty good job of quickly hydrating the body, beverages with a little bit of sugar, fat or protein do an even better job of keeping us hydrated for longer.
The reason has to do with how our bodies respond to beverages, according to Ronald Maughan, a professor at St. Andrews’ School of Medicine and the study’s author. One factor is the volume of a given drink: The more you drink, the faster the drink empties from your stomach and gets absorbed into the bloodstream, where it can dilute the body’s fluids and hydrate you.
Milk is more hydrating than water
The other factor affecting how well a beverage hydrates relates to a drink’s nutrient composition. For example, milk was found to be even more hydrating than plain water because it contains the sugar lactose, some protein and some fat, all of which help to slow the emptying of fluid from the stomach and keep hydration happening over a longer period.Milk also has sodium, which acts like a sponge and holds onto water in the body and results in less urine produced.
The same can be said for oral rehydration solutions that are used to treat diarrhea. Those contain small amounts of sugar, as well as sodium and potassium, which can also help promote water retention in the body.“This study tells us much of what we already knew: Electrolytes — like sodium and potassium — contribute to better hydration, while calories in beverages result in slower gastric emptying and therefore slower release of urination,” said Melissa Majumdar, a registered dietitian, personal trainer and spokeswoman for the Academy of Nutrition and Dietetics who was not involved in the study.
Sugar in moderation
But here’s where it gets tricky: Beverages with more concentrated sugars, such as fruit juices or colas, are not necessarily as hydrating as their lower-sugar cousins. They may spend a little more time in the stomach and empty more slowly compared to plain water, but once these beverages enter the small intestine their high concentration of sugars gets diluted during a physiological process called osmosis. This process in effect “pulls” water from the body into the small intestine to dilute the sugars these beverages contain. And technically, anything inside the intestine is outside your body.Juice and soda are not only less hydrating, but offer extra sugars and calories that won’t fill us up as much as solid foods, explained Majumdar. If the choice is between soda and water for hydration, go with water every time. After all, our kidneys and liver depend on water to get rid of toxins in our bodies, and water also plays a key role in maintaining skin’s elasticity and suppleness. It’s the cheapest moisturizer you’ll find.While staying hydrated is important — doing so keeps our joints lubricated, helps prevent infections, and carries nutrients to our cells — in most situations people don’t need to worry too much about how hydrating their beverages are.“If you’re thirsty, your body will tell you to drink more,” Maughan said. But for athletes training seriously in warm conditions with high sweat losses, or for someone whose cognitive function may be negatively impacted by working long hours without beverage breaks, hydration becomes a critical issue.
Can beer and lattes keep me hydrated?
Alcohol acts as a diuretic, which causes you to pass more urine, so when it comes to alcoholic beverages hydration will depend on a beverage’s total volume. “Beer would result in less water loss than whiskey, because you are ingesting more fluid with beer,” Maughan said. “Strong alcoholic drinks will dehydrate, dilute alcoholic drinks will not.”When it comes to coffee, how well your java hydrates you will depend on the amount of caffeine you consume. A regular coffee with about 80 milligrams of caffeine — roughtly what you would find in 12 oz. of Folgers’ house blend – would be pretty much as hydrating as water, according to Maughan’s research.Consuming more than 300mg of caffeine, or about 2-4 cups of coffee, could cause you to lose excess fluid as the caffeine causes a mild, short-term diuretic effect. This is more likely to happen with someone who doesn’t typically consume caffeine, and it could be offset by adding a tablespoon or two of milk to your cup of joe.
The EPA rolled back regulations on four of the innumerable “forever chemicals” that had been recently added to the regulatory list. Now thousands of PFAS chemicals remain unregulated. For a full discussion of the PFAS regulatory dilemma, see The Pure Water Gazette.
Wealthy tech companies are exhausting water supplies of the poorest and driest areas
The poorest and driest regions of South America are being pumped dry by giant international tech companies. The Guardian.
Trump’s Budget Request Contains Deep Cuts for the Nation’s Water Systems
On May 2nd, a letter to Appropriations Committee Chair Susan Collins revealed that President Donald Trump’s budget proposal for FY2026 calls for a sweeping $4.2 billion in total funding reduction for the U.S. EPA. $2.46 billion of this will be taken from the Clean and Drinking Water State Revolving Funds, or SRFs — slashing 89% of the FY2025 funding.
The Clean Water SRF (CWSRF) program provides funding for water infrastructure projects such as stormwater runoff mitigation, decentralized wastewater treatment systems, and water reuse.
Similarly, the Drinking Water SRF (DWSRF) program is dedicated to supporting and protecting water supply projects. The DWSRF is designed to help communities finance the maintenance of safe drinking water — significantly, replacing aging pipelines. After the Lead and Copper Rule Improvements (LCRI) issued in October 2024, the importance of distribution system investment has become even more paramount. Water Online
Phylate and heart disease
A study published April 29 in the journal eBiomedicin is the first to estimate heart disease deaths from exposure to di-2-ethylhexyl phthalate (DEHP), a class of phthalate chemicals that are used in raincoats, food packaging, shower curtains, PVC flooring and pipes, IV bags and other items. The chemicals make plastics softer and more pliable but are associated with multiple health problems, including hormone disruption, obesity, diabetes, infertility, cancer and heart problems. New Lede
Snow Crabs
Ten billion snow crabs, 90% of the Eastern Bering Sea population, have died off on the coast of Alaska largely due to warming ocean temperatures. Smithsonian
The nation’s biggest cities are sinking, according to data from a new study on “subsidence”
Known scientifically as land “subsidence,” the most common cause of the sinking is “massive ongoing groundwater extraction,” say the study authors, though other forces are at work in some places. The cities include not just those on the coasts, where sea level rise is a concern, but many in the interior. USA Today
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EPA Lifts 2016 Emergency Order on Drinking Water in Flint, Michigan
WASHINGTON – On Monday, May 19, U.S. Environmental Protection Agency (EPA) Administrator Lee Zeldin announced the City of Flint, Michigan has completed all requirements of EPA’s Safe Drinking Water Act (SDWA) emergency order and it will now be lifted. Since EPA issued the emergency order in January 2016, the City of Flint and the State of Michigan have worked cooperatively with EPA to address and complete all requirements. Water sampling shows that Flint’s water system is now in compliance with lead standards, a major milestone accomplished through years of cooperative federalism dating back to 2016, culminating in the termination of this emergency order.
Adios Fluoride
States are beginning to discontinue the addition of Fluoride to drinking water. The trend is growing fast. In addition, the FDA in May announced that supplemental Fluoride treatment will be removed from the market.
Texas experiencing record heat and water scarcity
Texas is experiencing a scorching, early heatwave, with temperatures across the central and southern region of the state ranging from 100F to 111F – record-breaking for this time of year. These parts of the state have recently been hotter than Death Valley, California, the hottest place on Earth. The Guardian.
Older PFAS Concentration in Foods on the Decline according to a new study
While concentrations of older “forever” chemicals appear to have decreased in many foods over the last two decades, a new study found that drinking water, along with seafood, eggs, and brown rice, still contribute to PFAS exposure in adults. More attention is needed to newer, replacement PFAS.
Food has long been considered a major source of per- and polyfluoroalkyl substances (PFAS), a large class of long-lasting chemicals used in industry, consumer products, and found in the environment that are hazardous to human health. A new study led by School of Public Health researchers reveals that PFAS exposure through food appears to have declined among adults over the last two decades—but drinking water remains an important source of these chemicals. In related PFAS news, The EPA has announced it will uphold the current enforceable limits for PFOA and PFOS at 4 parts per trillion in drinking water. However, the agency plans to rescind regulations for four other PFAS compounds. Water Online.
Ten Dirtiest Beaches in CA
The LA Times listed the state’s 10 dirtiest beaches. LA Times for the full article.
Last week, environmental groups decried plans from the Environmental Protection Agency to rescind and “reconsider” drinking water limits for four per- and polyfluoroalkyl substances, or PFAS, compounds linked to cancer and damage to the immune and endocrine systems, among other health effects.
The limits had been finalized by Joe Biden’s administration last April as part of an effort to limit people’s exposure to hazardous “forever chemicals.” Out of a total of more than 10,000 known PFAS, they targeted just six of the most concerning ones. The Trump administration’s EPA said it would retain the limits for two of the PFAS but give utilities more time to comply with them and scrap the others. One advocate called the EPA’s move a loss for public health and a “victory for chemical companies.”
But how protective were the Biden regulations to begin with? And how much of a difference will it make to pare them back?
The chemicals have become so ubiquitous in people and the environment because of their use in everything from outdoor clothing to cooking utensils and food packaging. Runoff from firefighting foam, infused with the chemicals, has contributed to widespread drinking water contamination, along with manufacturers’ deliberate dumping of the chemicals into rivers — despite knowing about their health risks.
Once they’re created, PFAS don’t break down naturally; hence the moniker “forever chemicals.” Regulating them is an “important win,” experts have said, one that “allows the country to begin cleaning up the mess in its water.”
But the fight over drinking water limits for individual PFAS distracts from the larger context that there are thousands of types, and scientists suspect they all have similar health effects. Even last year, when the Biden administration first announced its national drinking water standards, scientists criticized it for addressing PFAS on a chemical-by-chemical basis. “The EPA is trying to regulate six forever chemicals. Just 10,000 to go,” as the title of an op-ed by one Harvard researcher put it.
Erik Olson, a senior strategist for the nonprofit Natural Resources Defense Council, said the U.S. is “stuck in a Whac-a-Mole game” with PFAS, in which only the best researched compounds are regulated. Lesser-known compounds may be just as toxic — thanks to their similar chemical structures — but escape regulations just because they haven’t been studied, he added. “What we need to do is control PFAS as a class.”
Of the six forever chemicals targeted by the Biden administration’s original policy, PFOA and PFOS are the most prevalent and, consequently, they’ve been researched the most extensively. Those compounds got the strictest drinking water limits of 4 parts per trillion, the lowest level at which they can be detected, reflecting scientists’ understanding that there is no safe exposure level for them. Three additional compounds — PFNA, PFHxS, and GenX — were given a contamination limit of 10 parts per trillion. Water utilities were instructed to use a “hazard index” to monitor a sixth chemical, called PFBS, as well as mixtures of the chemicals.
The Trump EPA said it would keep the PFOA and PFOS drinking water limits but give utilities until 2031 to comply with them, instead of 2029. The rules for the other four compounds will be scrapped and reevaluated. The EPA said it intends to finalize its replacement regulations by next spring.
A statement from EPA Administrator Lee Zeldin said the extended timeline for PFOA and PFOS would provide “common-sense flexibility” to utilities, some of which sued the EPA over its regulations last year. The utilities said the EPA’s new rule was too strict and would cause unreasonable compliance costs.
A spokesperson for the EPA told Grist that the process by which the agency had “promulgated the preliminary regulatory determinations simultaneously with the proposed regulation” for PFNA, PFHxS, GenX, and PFBS under the Biden administration “was inappropriate and may not comply with the statutory requirements of [the] Safe Drinking Water Act.” With regard to the rescissions, they said that “while EPA cannot predetermine the outcome, it is possible” that the agency will issue more stringent requirements this spring.
Daniel Jones, an emeritus professor of molecular biology at Michigan State University, said the impacts of the Trump administration’s reversal will depend on geography. Communities primarily affected by PFOS and PFOA may not be greatly affected, since the standards for those chemicals remain in place — albeit with an extended timeline for compliance. To meet the standards, water utilities will likely have to install something like an activated carbon filtration system, he said, which is effective at removing “long-chain” PFAS like PFOA and PFOS, which have a larger chemical structure than compounds like GenX.
Putting these filtration systems into place will thankfully sweep up more PFAS than just PFOA and PFOS, Jones said.
States like North Carolina, Ohio, and West Virginia, however, face disproportionate contamination from GenX due to production facilitiesconcentrated there. This contamination could continue unabated if the standard for the compound is eliminated. According to Olson, some of the technologies that remove PFOS and PFOA are not as effective at attracting GenX. “To really control the full suite of PFAS, we need to go to more advanced technologies like tight membranes, like reverse osmosis,” he said.
Some water utilities may opt for these more advanced — and expensive — technologies if they believe that they will eventually be required to test for and limit a much larger number of PFAS, Olson added.
Although Jones is disappointed that the EPA intends to drop regulations for the four PFAS, he said he is more concerned about a single clause in the EPA’s press release, about the EPA’s intent to establish a “federal exemption framework” for the PFOS and PFOA limits. The release contains no further information about what this would entail, but Jones worries it could allow water utilities to circumvent the federal government’s water quality requirements altogether. “It seems that an exemption framework is likely to open the door to say, ‘This is going to cost too much, you don’t have to do it,’” he said.
The EPA spokesperson said exemptions would not allow utilities to violate regulations: “Rather, they allow additional time to find a compliance solution.”
Jones also raised concerns about funding for further PFAS research, including investigations on how exposure to mixtures of the chemicals may impact human health. One of his federal grants for PFAS research was recently cut by the Trump administration, he said, and a colleague at Michigan State University studying PFAS on farms has also had his funding rescinded.
In addition to regulating PFAS by groups or as a class, Jones said the EPA should set pollution standards using what’s known as the “precautionary principle,” which doesn’t require definitive evidence about a chemical’s harms before it can be regulated. “In some countries, if you want to release a chemical into the environment you have to show it’s safe,” he said. “The U.S. usually takes the opposite approach and says, ‘You can use these chemicals … and if we find that there’s a problem, then we’ll come up and regulate [them].’”
Olson believes the EPA’s alterations to the PFAS rules are in violation of the Safe Drinking Water Act’s “anti-backsliding provision,” which says any revision the EPA proposes to a drinking water standard must be at least as protective of public health as the previous one. The law also caps compliance timelines at five years, whereas postponing the PFOS and PFOA compliance deadline to 2031 would give water utilities seven years.
“Ultimately, we need to be phasing these chemicals out,” Olson added. “We have to turn off the spigot and stop using these things so that five generations from now, our great-great-great grandchildren won’t be dealing with them.”
Introductory Note: The article reprinted here is a commercial from the Calgon Carbon Corporation and it is pointed toward large municipal or industrial water treatment plants. We’re reprinting it because the same principles that work in the gigantic filters in question also apply to residential water treatment. The article explains well that GAC is not a magic solution for all water issues and planning is required if specific contaminants are to be addressed effectively. For example, chlorine reduction is easy but you should not expect a GAC unit that is treating chlorine to be just as effective with VOCs or PFAS. Adequate sizing and planning are required.
Due to increasing regulations and an ever-rising understanding of contaminants present in many drinking water sources, water treatment plants (WTPs) are more frequently tasked with addressing multiple contaminants. To many engineers and WTP managers, having to remove one or more contaminants often means adding multiple targeted removal systems. However, it is possible for a single system to be a multi-contaminant solution.
For years, the U.S. EPA has recognized granular activated carbon (GAC) as a best available technology (BAT) for a wide range of organic contaminants, many of which can be addressed within the same system. Calgon Carbon’s FILTRASORB® GAC is proven to be a highly effective solution for removing multiple contaminants from drinking water, including total organic carbon (TOC), disinfection byproducts (DBPs), per- and polyfluoroalkyl substances (PFAS), 1,2,3-tricholoropropane (1,2,3-TCP), taste and odor (T&O), volatile organic compounds (VOCs), and algal toxins. Calgon Carbon also stands alone in the market as the only total solutions provider, offering virgin GAC, reactivated GAC, equipment, and specialized support services.
Historical Use Of GAC
Initially used to tackle taste and odor, GAC filtration has been a part of drinking water treatment since the 1930s in the United States. With the passage of the Safe Drinking Water Act (SDWA) 50 years ago, GAC treatment has evolved to encompass additional target contaminants such as VOCs, TOC, DBPs, and more. Today, water utilities are once again turning to the effective and simple solution of GAC filters for the removal of PFAS from their source waters to protect their constituents and enhance the quality of our nation’s drinking water.
Why GAC Works So Well
You may be wondering why GAC filtration has been deemed a BAT for a vast variety of contaminants. Simply put, unlike other treatment technologies, GAC media is not manufactured to target one specific contaminant. Instead, GAC media removes organic contaminants in the water stream, regardless of type, through the process of adsorption. Adsorption is governed by the kinetics of diffusion and is powered by electrostatic forces, called Van der Waals forces, which cause the organic contaminant to stick to the surface of the GAC media, thereby removing it from the water stream. Diffusion is governed by both media properties and contaminant properties and describes the time required for the contaminant in the water to be adsorbed onto the media. Several organic contaminants share similar diffusion characteristics, thereby making it possible to remove multiple contaminants simultaneously in one GAC filter, provided there is enough contact time and media capacity. Given the importance of both contact time and media capacity, Calgon Carbon’s FILTRASORB 400 paired with their AquaKnight™ Gold Certified (GC) Adsorption Systems, which utilize a cone bottom underdrain to enhance flow distribution, can be an excellent solution for WTPs looking to tackle multiple contaminants with one treatment process. For more information on Calgon Carbon’s AquaKnight GC Systems and to reach a Calgon Carbon representative directly, please go to https://www.nomorepfas.com/contact/
Using GAC For Multiple Contaminants
As previously mentioned, the effectiveness of GAC filters at removing multiple contaminants depends on both the media selected and the equipment design, specifically the empty-bed contact time (EBCT). For instance, an EBCT of around 7 minutes may suffice for removal of most VOCs, while PFAS typically requires about 10 minutes. If a GAC system is already in place for VOC removal, engineers or operators can collaborate with the media vendor, such as Calgon Carbon, to identify and evaluate the pathways available to target additional contaminants of interest within the same filter. Some of those pathways include changing the GAC media installed, changing the flow rate through the filter, improving the performance of upstream processes, or adding GAC filters in parallel or series to the existing system. In certain situations, no changes are required at all. However, if needed, an existing GAC system can be tweaked to enable simultaneous treatment for multiple contaminants, leading to a better tasting, more stable, and higher quality drinking water.
Ultimately, it is recommended that WTPs and engineers undertake a comprehensive pilot study to determine the best approach to removing their contaminants of concern. This will not only help identify the right carbon type and vendor for the contaminants in question but also the expected media life for the system. If a pilot test is not an option, a rapid small-scale column test (RSSCT) can be used to provide some insights, though their accuracy is not as reliable as a pilot. It is imperative in either case that the team conduct the test work with an experienced media vendor to ensure the correct assumptions are factored into the analysis. For example, Calgon Carbon is the only vendor that offers a complete pilot testing package, which includes pilot testing equipment, media, technical assistance, and modeling using the EPA’s free AdDesignS software to provide clients with a holistic analysis of the results.
Alternatives To GAC
Although technologies such as IX media can sometimes be effective at removing some sulfonated PFAS compounds, they often require specific water matrices (low anion and dissolved metals content) to be more cost effective than GAC media. Moreover, IX medias, and more recently novel sorbents, provide none of the additional benefits that are typically associated with GAC, such as decreasing VOCs and TOC/DBPs, protecting the water supply against chemical spills in the watershed, and improving taste and odor.
For those operations that are already utilizing GAC filters, adjusting operational setpoints to handle new contaminants is generally the best path forward for a range of reasons. In addition to minimizing new capital expenses, it also reduces or eliminates the training associated with adding new treatment technologies. While leveraging the same media beds for additional contaminants can shorten the bed life with respect to the least adsorbable contaminant, the increase in changeouts is typically still less costly from a lifecycle perspective than adding a new removal technology. Ultimately, there are few alternative technologies to GAC that can simultaneously remove multiple contaminants, with none being as straightforward and easy to integrate from an operational standpoint and some being significantly more expensive.
GAC Treatment Is A Viable Solution
As the need for comprehensive water treatment solutions continues to grow, GAC remains one of the most dependable and scalable technologies for delivering high-quality drinking water. By integrating Calgon Carbon’s FILTRASORB GAC into the drinking water treatment process, utilities can reliably achieve comprehensive contaminant removal and regulatory compliance. Calgon Carbon is the only total solutions provider and stands ready with virgin and Custom Municipal Reactivated (CMR) FILTRASORB GAC, AquaKnight™ GC equipment, and a team of dedicated field service personnel and technical experts to help utilities meet their water treatment goals.
