SLO County drinking water wells contain cancer-linked chemicals — here’s how to protect yourself
Drinking water wells in two areas of San Luis Obispo County are contaminated with potentially toxic “forever chemicals,” according to recently released results of state water testing.
The local testing found that 15 wells in San Luis Obispo and Atascadero had levels high enough to require notification to water system governing boards.
In April, the State Water Resources Control Board began testing drinking water wells throughout California for perfluoroalkyl and polyfluoroalkyl substances — also known as PFAS. The chemicals have been used in firefighting foam, as well as waterproof clothing and non-stick cookware and food wrappers.
“This stuff is everywhere,” said Jeff Densmore, an engineer for the District 6 Division of Drinking Water, of PFAS use in consumer products.
PFAS substances are known as “forever chemicals” because they’re human-made and don’t break down easily, meaning they can remain in the body and cause harm. They can be toxic at even the tiniest parts per trillion levels, which is how the State Water Board measures them.
The most-studied PFAS chemicals — perfluorooctanoic acid (PFOA) and perfluorooctanesulfonic acid (PFOS) — are associated with pregnancy complications, liver damage, decreased fertility and an increased risk of thyroid disease, among other health problems, according to the State Water Board.
PFOA has also been classified as possibly cancer-causing, according to the International Agency for Research on Cancer.
Producers have been phasing out PFOS and PFOA production in the United States, but the chemicals continue to exist in the environment. New PFAS substances are also being developed.
SLO County well testing
The State Water Board in April issued orders to test wells near airports and landfills — areas where PFAS substances could most easily get into the water.
Wells that had been found to contain PFOS and PFOA during previous tests were also included.
State regulators are conducting quarterly tests to establish maximum thresholds for PFAS chemicals, which will help them ensure there aren’t toxic levels of substances in drinking water.
In San Luis Obispo County, staff tested 24 wells, most of which are located near the San Luis Obispo County Regional Airport and in Atascadero.
The State Water Board broke the wells down into three groups.
- No notification: Water systems with wells found to contain less than 5.1 parts per trillion (ppt) of PFOA and 6.5 ppt of PFOS aren’t required to notify governing boards or customers.
- Notification: Systems with wells found to contain at least 5.1 ppt of PFOA and 6.5 ppt of PFOS are required to report the results to their governing boards and are urged to notify customers.
- Response: Systems with wells found to contain combined PFOA and PFOS levels of at least 70 ppt should consider treating their wells or taking the water source out of service entirely.
Water systems whose wells contain combined PFOA and PFOS levels of 100 ppt fell into the “response” category and also received a special designation as having high PFAS levels.
Nineteen private San Luis Obispo-area wells were tested. Eight wells required no notification. Contamination in seven wells reached the notification level, two required responses and two were so bad they were also designated as having high levels of PFAS chemicals.
Five Atascadero Mutual Water Co. wells were also tested. Although they’re not located near airports or landfills, previous testing showed wells contained PFAS chemicals, Densmore said.
One well required no notification. Contamination in the remaining four wells reached the notification level.
The Atascadero wells feed into the city’s public water system. Most of the San Luis Obispo wells are located near business parks and industrial office areas.
Those who live or work near a contaminated well should contact the person in charge of their building’s utilities to verify the source of their drinking water.
They can also contact county Environmental Health Services to learn which system supplies their drinking water.
A State Water Board lookup tool allows some customers to see where their water comes from, but not all suppliers are mapped.
How customers can protect themselves
The State Water Board recommends specific filtration processes for cutting down on the amount of PFAS chemicals in drinking water.
Carbon — including granular activated carbon and powdered activated carbon — and reverse osmosis treatments are among the most effective.
Densmore recommends customers purchase devices certified by consumer safety group NSF, which conducts product testing.
Hague Quality Water in San Luis Obispo and Santa Barbara counties installs carbon and reverse-osmosis devices, although they’re not NSF-certified, said Eric Foronjy, sales manager.
Most of Hague’s customers are in the North County, so Foronjy recently ran an Atascadero Facebook ad asking if customers had any questions about contaminated wells in the area.
“It’s so far under people’s radars,” he said.
Foronjy has not yet installed any water systems to address customer concerns about PFAS chemicals. He said worried customers can first have their water tested at a lab, such as Abalone Coast Analytical in San Luis Obispo.
If they receive troubling results, Hague can design a system for them and then retest the water, Foronjy said.
For more information, visit waterboards.ca.gov/pfas. To contact San Luis Obispo County Environmental Health Services, call 805-781-5544.
Correction: This article has been updated to place engineer Jeff Densmore’s quote in a more accurate context. The most recent update also includes information on how to contact San Luis Obispo County Environmental Health Services.
This story was originally published October 30, 2019 at 3:36 PM.
