Does San Marcos Water Have PFAS...
And What Can I Do About It?

PFAS, often referred to as “Forever Chemicals,” have been detected in the San Marcos water supply. These compounds are part of a growing national concern because they do not easily break down in the environment or the human body over time.

San Marcos utilities receive water from a combination of the Edwards Aquifer, Carrizo-Wilcox Aquifer, and Canyon Lake surface water sources. Recent water quality testing detected several PFAS compounds in the local water supply at trace levels, including:

Some of these reported levels exceeded the laboratory reporting threshold listed in the water quality data. PFAS compounds are commonly associated with products such as stain-resistant coatings, food packaging, carpeting, textiles, and firefighting foams. Because these chemicals persist in the environment, they are increasingly being detected in water systems across Texas and the United States.

While the reported levels in San Marcos remain relatively low, PFAS continue to be studied due to concerns surrounding long-term exposure and bioaccumulation. Many homeowners choose to install additional water filtration systems, such as reverse osmosis or activated carbon filtration, to help reduce PFAS and other emerging contaminants in drinking water.

There is no way for you prevent PFAS contamination in the environment, but you can make sure the water you’re drinking is PFAS free. If there is good news regarding PFAS water contamination, it’s that they can be treated and removed from water with the right filtration. For example, several methods, like carbon filtration, ion exchange, and reverse osmosis water treatment effectively remove PFAS from water.

On April 10, 2024, the United States government introduced its first-ever national, legally enforceable drinking water standard to protect citizens from PFAS forever chemicals. The new rules to regulate six types of PFAS chemicals were developed based on feedback from the public and stakeholders, with over 120,000 comments considered. The EPA believes that these rules will protect about 100 million people from PFAS exposure over time, prevent thousands of deaths, and reduce tens of thousands of serious illnesses related to PFAS.

The EPA has also announced that it will be offering substantial funding, including $1 billion from the Bipartisan Infrastructure Law, to help test and treat PFAS in not only public water systems but address contamination in private wells as well.

The new regulations set limits known as ‘Maximum Contaminant Levels or MCLs’ for individual PFAS like PFOA, PFOS, PFHxS, PFNA, and HFPO-DA, as well as a combined limit for mixtures of PFHxS, PFNA, HFPO-DA, and PFBS. While these regulations will help to protect from 6 PFAS, there are over 15,000 PFAS chemicals.

The new regulations state areas exceeding the new standards of PFAS contamination must take action to reduce PFAS in their drinking water within 5 years.

On May 18, 2026, the U.S. Environmental Protection Agency announced proposed changes related to PFAS drinking water regulations. The update keeps federal drinking water limits for PFOA and PFOS in place, but it may change how certain parts of the rule are implemented.

Under the proposal, some public water systems may be able to request additional time to meet enforceable limits for PFOA and PFOS. The EPA also proposed reviewing parts of the rule related to PFHxS, PFNA, HFPO-DA, commonly known as GenX chemicals, and the PFAS hazard index.

For homeowners, the update is a reminder that PFAS regulations are still developing. Public water systems may need time to test source water, review treatment options, secure funding and install new treatment equipment. In the meantime, homeowners who are concerned about PFAS can take a more immediate step by learning more about their own water quality.

Culligan offers professional water testing and filtration solutions designed to help reduce PFAS in drinking water. Depending on your home’s water quality, treatment options may include reverse osmosis, activated carbon filtration or other advanced filtration systems.

PFOA, the most notable substance of the PFAS family, was found to be a part of the manufacturing process of Teflon. The EPA sued DuPont in 2005 for failing to report a health risk to both humans and the environment. The company paid a $10.25 million settlement.

Because of PFOA and PFAS strong molecular structure, they take much longer to break down naturally than other organic chemicals.

Until 2002, PFOA were integral in producing goods which qualities repel dirt, grease, water and stains.

These contaminants can be found in the manufacturing process of a variety of products, including non-stick cookware, carpet-care liquids, treated apparel, upholstery or textiles, sealants, dental floss, floor wax and non-woven medical garments. Though PFTE non-stick cookware was proven to have PFOA levels, a recent study found levels that ranged from undetectable to 4.3 parts per billion, and it is not currently considered a major pathway for PFOA.

Just last year, United Nations experts recommended banning PFOA globally at the Stockholm Convention on Persistent Organic Pollutants. Will the United States follow suit based on recent outbreaks in Texas and Michigan.

According to a study from 2002-2005, people who lived in the PFOA-contaminated area around DuPont’s Washington Works facility were found to have higher levels of PFOA in their blood from drinking water. People that drank more tap water, ate locally grown fruits and vegetables, or ate local meat, were all associated with having higher PFOA levels.

Residents who used carbon filter systems had lower PFOA levels.” Studies have found that using carbon-activated filters can reduce PFOA by up to 60%.

The EPA has issued a “Health Advisory” for PFOA and PFAS, but this does not amount to any actual forced federal regulations on municipalities to control and monitor them.

The EPA has established health advisory levels at 70 parts per trillion as of 2020.

How Much Is 70 Parts Per Trillion?

To compare 70 parts per trillion, think of a drop of ink in a backyard pool. According to its website, “EPA’s health advisory level for PFOA and PFOS offers a margin of protection for all Americans throughout their life from adverse health effects resulting from exposure to PFOA and PFAS in drinking water.”

A few of the adverse health conditions a lifetime of exposure can lead to are develop- mental effects in children, kidney and testicular cancer and immunodeficiency disorders.