Pure Water Occasional. May, 2025
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In this Springtime Occasional you'll hear about the excellence of undersink water filters, the value of wastewater testing, the changing rules of PFAS regulation, severe federal cuts to funding of water programs, phylates, Snow Crabs and their problems, "subsistence," the end of Flint's drinking water saga, California's dirtiest beaches, the demise of public water fluoridation programs, cartridge-style whole house water filters, how to diagnose and fix reverse osmosis shutoff issues, and, as always, there is much, much more.
Thank you for reading, and sincere thanks from Pure Water Products for your continuing support. |
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Please visit the Pure Water Gazette, where you will find hundreds of articles about water and water treatment, and the Pure Water Products main website, where there is much information about water treatment and specific information about the products we offer. On both of these information-rich sites, pop-up ads and other distractions are not allowed.
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Pure Water Gazette Technical Wizard Pure Water Annie Answers All the Persistent Questions about Water Treatment.
Gazette Technical Consultant Pure Water Annie explains how undersink water filters have improved in recent years.
An undersink water filter is a treatment device that is inststalled
under the kitchen sink but dispenses its treated water on the sink top.
This is a very practical and efficient arrangement because it leaves the
countertop uncluttered but allows plenty of equipment space for
excellent filtration.
Several improvements in recent years have made undersink filters
extremely effective, practical, and easy to install and service. These
include
- The replacement of copper and galvanized undersink piping with flexible connectors.
- The improvement in filter housing and cartridge designs that allows
installation of more compact and easy-to-service filtration units.
- The improvement in filtration technology that allows targeted treatment of many more problem contaminants.
The use of flexible undersink pipes not only makes installation of
standard undersink filters with their own dispensiing faucet much easier
and safer, it also allows very easy installation of “simple” undersink
filters, the type that dispense water through the existing cold water
side of the sink faucet rather than an added ledge faucet. (For the
difference between “simple” and standard undersink filters, see How Undersink Filters Work.)
Modern filter housings are now available that make cartridge changes
as easy as changing a light bulb. Even traditional housings have been
improved so that the best brands are easy to open and virtually
leak-proof.
Carbon block filters have been steadily improved over the years so
that now extra fine powdered carbon provides much more effective
filtration and greatly increased cartridge life as compared with old
granular carbon filters. In addition, cartridges can now be made to
target specific contaminants like lead, arsenic, fluoride, iron,
bacteria, nitrates, low pH, and cysts.
This last aspect, the use of “media cartridges” for special purposes,
is especially effective with multi-filter undersink units that use two
or more canisters with different cartridges.
The classy triple undersink filter shown above has exceptional
chlorine/chloramine reduction capacity and can, depending on the
cartridges chosen, remove such contaminants as bacteria, cysts,
nitrates, colors, sediment, odors, lead, iron, arsenic, fluoride, and
more. Go here for a listing of cartridges that will fit this filter.
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Water News for May 2025
The new EPA cancels regulations on PFAS
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
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.
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Basic Heavy Duty Whole House Cartridge Filters
Tough, versatile 20-inch “Big Blue” housings can be used alone or in a
variety of combinations to meet virtually any “whole house” filtration
situation. They are simple, durable, easy to install, and easy to
service. They use standard-sized cartridges so replacements are easy to
find.
Parallel installation, as pictured below, make them suitable for
even large homes. Installing in parallel greatly reduces pressure loss,
enhances the effectiveness of the unit, and extends the life
expectancy of the cartridges.
Cartridge filters are much easier to maintain than tank-style
filters. As for installation, they are compact in size and do not
require electricity or connection to a drain. Most require only an
annual cartridge change, which can usually be done by the homeowner.
The chart below shows sizing suggestions for whole house filtration for water that is treated with chlorine or chloramine. Chloramine units require more expensive cartridges than than the unit treating chlorine.
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Description
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Application
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To Determine Pricing
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| System 1. One 4.5″ X 20″ 5 micron sediment filter plus one 4.5″ X 20″ high performance carbon filter. |
Homes with 1 to 3 people. Flow rates to 5 gpm. |
Price is the same as WH103 on this page. |
| System 2. One 4.5″ X 20″ 5 micron sediment filter plus two 4.5″ X 20″ carbon filters installed in parallel. |
Homes with up to 5 people. Flow rates to 10 gpm. |
Price is the same as one WH103 and one WH102 on this page. |
| System 3. One 4.5″ X 20″ 5 micron sediment filter plus three 4.5″ X 20″ carbon filters installed in parallel. |
Homes with up to 8 people. Flow rates to 15 gpm. |
Price is the same as one WH103 and two WH102 on this page. |
Basic Housing and Bracket Setup. The Housing is available for
3 pipe sizes–3/4″, 1″, or 1.5″. This very versatile “Big Blue” housing
will accept any standard 4.5″ X 20″ cartridge. It can be used for
sediment cartridges, carbon cartridges, or “media” cartridges for
special purposes like iron removal or pH increase.
Basic Parallel Arrangement for Sediment Filter followed by two Carbon Filters installed in parallel. This arrangement increases service flow rate, extends cartridge life, and greatly increases effectiveness.
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Reverse Osmosis Shutoff Problems
Here is a typical customer question regarding an undersink reverse osmosis unit that doesn’t seem to be shutting off properly.
In the past week or so we’ve noticed a dramatic uptick — or trickle — of the filter. That is, we’ve been hearing sometimes for a couple hours at a time, for a week every day, what I’m calling the usual but much less frequent “back flow” into the drain pipe that happens during filtration under normal conditions. Whereas it used to be heard only once a month — in other words, so infrequently that we almost didn’t notice it.
The “backflow” that the RO owner describes is actually the unit’s normal flow to drain. Whether you hear it or not, there is always a trickle of water running to the drain while the unit is filling the storage tank. The drain water’s function is to carry away the impurities that have been rejected by the RO membrane. The trickle to drain happens when the unit is making water to fill the tank. When the tank is full, it stops.
RO Units Don’t Follow Human Logic
There are a number of reasons why you start hearing water run into the drainpipe when you have not heard it before. The most common are a change in water pressure or a change in temperature, causing the water to fall a bit differently into the drain pipe. When drain water slides down the wall of the pipe, you don’t hear it, but if the pressure is a bit stronger it can fall into a small pool of water that has gathered in the pipe and you’ll hear it fall. (If the drain saddle is installed on a horizonal rather than a vertical pipe, you will hardly ever hear the drain flow.)
If it sometimes takes much longer than you would expect to fill the storage tank, that’s usually because the unit’s production was shut off prematurely with the tank only partially full. The next time the unit begins making water, it will take longer than you expect to refill the storage tank. Here’s a common situation. The unit is filling the tank when an event like a toilet flush or a shower lowers incoming pressure and the production stops because the shutoff system thinks that the tank is full. (Yes, I know, RO units don’t think.) The way that the shutoff system determines the amount of water in the tank is by monitoring the pressure inside the tank and comparing it to the pressure of the tap water going into the unit. The unit fills the tank until the pressure in the tank equals about 2/3 of the pressure of the inlet water. If the inlet pressure goes down (as happens when a toilet is flushed), the production of water to fill the tank can be interrupted. The next time there is a demand for water (e.g., the RO faucet is opened), the pressure in the storage tank goes down and production starts. In this case it will take a lot longer to top off the tank than you would expect.
To Determine If There Is a Problem
The first thing to do is to determine if the shutoff system is working.
Probably the easiest way to determine if the system is working is before going to bed to run enough water through the unit to start production, then check it the next morning. If it has shut off during the night everything is probably working fine.
A quicker way is to turn off the valve on top of the storage tank (off is with the valve handle at right angles with the tube), then open the countertop RO faucet. The water should run at a uniform trickle or small stream. Next, turn off the faucet. Water should stop running to drain within 3 or 4 minutes. If it stops production and keeps it off, the shutoff system is working fine. Turning off the tank valve simulates a full tank.
If water continues to run with the tank valve closed, the unit needs attention. The most likely parts that need replacement are the hydraulic shutoff valve (the disc-shaped part mounted on the membrane housing that has 4 tubes) or, less likely, the check valve (one way valve) in the permeate tube. It is the small cigar-shaped item in the short tube that connects the left end of the membrane housing with the shutoff valve.
Red Flag
If the water you hear in the drain line sounds more like a rushing river than a gentle trickle and it never stops, turn off the inlet water to the unit and leave it off until a repair is made. The offending part is the flow restrictor. That’s the larger of the two cigar-shaped items in the drain tube.
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From New York to Los Angeles, cities in the United States are sinking. According to a recent study, which looked at the 28 most populous cities, all were sinking to some degree. The authors of the study point to massive ongoing groundwater extraction as the most common cause.
The study, conducted by Columbia Climate School, used satellite data to map out land movements. In 25 of the 28 cities studied, two-thirds or more of their area is sinking. By taking these measurements and correlating the data to land movements, the researchers determined that 80% of the sinkage was caused by groundwater removal for human use.
Perhaps unsurprisingly, Houston was identified as the fastest-sinking city. Given Texas’ continuous struggle against droughts, as well as oil and gas extraction, the state has been known to face water issues.
Among other causes for the sinking cities included natural forces, and even the weight of buildings. In New York City particularly, the 1.1 million buildings are pressing down on the land and contributing to sea-level rise.
Besides increased flood risk, this sinking could prove problematic for U.S. infrastructure. “Even slight downward shifts in land can significantly compromise the structural integrity of buildings, roads, bridges, and railways over time,” said Leonard Ohenhen, lead author of the study.
With this information in mind, the authors of the study encouraged cities to focus on finding solutions. They point to land raising, enhanced drainage systems, and green infrastructure as potential mitigation. “As opposed to just saying it’s a problem, we can respond, address, mitigate, adapt,” Ohenhen said.
As American cities continue to grapple with the dual threats of sinking land and rising seas, the findings of this study offer not just a warning, but a call to action. From improved water management to investment in resilient infrastructure, there is still hope for stability for these sinking cities.
Source: Water Online
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Places to visit for additional information:
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Pure Water Products, LLC, 523A N. Elm St., Denton, TX, 76201. www.purewaterproducts.com. Call us at 888 382 3814, or email pwp@purewaterproducts.com. |
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