PFAS compounds are difficult to detect. They exist in most products at extremely minuscule levels. It's only recently that laboratory testing technology could detect them at the levels being discussed.

Technological advances now allow us to detect concentrations in the parts-per-trillion (ppt) range. For perspective, a part per trillion is one drop of water in 20 Olympic-sized pools. The health advisory limits, however, are below what can be currently detected.

The scientific understanding and regulatory response to these compounds is uncertain but rapidly evolving. This includes potential public health implications.

Castle Rock Water is closely monitoring the new EPA drinking water health advisories for PFAS chemicals and will be working with the state to protect public health. Castle Rock Water uses the latest and best technology available to monitor and safeguard your drinking water.

National drinking water quality standards are set by the EPA and administered in our state by the Colorado Department of Public Health and Environment (CDPHE). Under the Safe Drinking Water Act, the EPA issues national health-based standards for drinking water to protect against both naturally occurring and man-made substances that may be found in drinking water.

To date, PFAS compounds (a group of thousands of per and polyfluoroalkyl substances) are not regulated. Recently, the EPA released new recommendations, known as health advisories, on two compounds, GenX and PFBS, and lower health advisories for PFOA and PFOS and is evaluating additional actions to address other PFAS.

Castle Rock Water is preparing for these future regulations and is currently using granular activated carbon, one of the best treatment technologies available for removing PFAS from water, to remove PFAS down to laboratory reporting levels.

A health advisory provides information on substances that can cause negative human health effects. Health advisories are non-enforceable and non-regulatory.

The health advisory levels were calculated to offer a margin of protection for all people, including sensitive populations and ages, against adverse health effects and take into account other potential sources of exposure beyond drinking water (for example, food, air, consumer products, etc.). Because these substances have been used in an array of consumer products, most people have been exposed to them and have them in their systems. According to the Centers for Disease Control (CDC), the average concentration (geometric mean) measured in the general U.S. population during 2017-2018 was 1.4 parts per billion (ppb) of PFOA and 4.3 ppb of PFOS. For comparative purposes, this average blood level is 1,400 parts per trillion (ppt) for PFOA when the health advisory in water is 0.004 ppt.

Research has shown that there may be health effects associated with exposure to some PFAS. Because there are many types of PFAS chemicals, which often occur in complex mixtures and in various everyday products, researchers face challenges in studying them. More research is needed to fully understand all sources of exposure, and if and how they may cause health problems. The National Institute of Environmental Health Sciences (NIEHS) provides updated information on health effects as well as a searchable database of published scientific papers about PFAS.

In 2022, Castle Rock Water collected over 3,000 samples and conducted tests throughout our system to ensure that the water we deliver to your home is as clean and safe as possible, and meets or exceeds all state and federal regulatory standards. Every year, we provide a Water Quality Report that shows the results of our continuous laboratory testing for regulated substances. To date, PFAS compounds are not regulated.

Prior to June 15, 2022, the EPA had a health advisory limit for two PFAS compounds (PFOA and PFOS) at 70 parts per trillion (or 0.07 ppb). Castle Rock Water's drinking water had tested well below that limit for PFOA and PFOS.

With the installation of our Advanced Treatment processes in 2020, Castle Rock Water began to regularly conduct additional testing for non-regulated contaminants such as PFAS.

• Prior to June 15, 2022, only PFOA and PFOS had advisory limits set at 70 parts per trillion (ppt).
• As of June 15, 2022, the EPA released much lower health advisories for two PFAS compounds PFOA and PFOS and issued health advisories for two new compounds - GenX and PFBS.
• Castle Rock Water has been sampling at our Plum Creek Water Purification Facility for these four PFAS substances as well as many others since July 2020. Results of the sampling at the entrance to our distribution system at the Plum Creek Water Purification Facility are shown below.

_{ND = Non-detect | ^nanograms per liter (ng/L) = parts per trillion (ppt)}

Castle Rock Water will continue testing for PFAS at the Plum Creek Water Purification Facility as part of our monitoring protocols. While we can effectively treat and remove PFAS at the Plum Creek Water Purification Facility, we regularly examine our treatment system and adjust these processes as part of our mission to provide safe, dependable and sustainable water now and in the future.

In 2023, Castle Rock Water as well as all other water providers across the United States will be required to collect samples for PFAS at all of their water supplies to their water distribution system. Results from this testing will likely be available by the end of 2023. Castle Rock Water will keep our customers updated on the progress of this sampling.

Public health and the quality of your drinking water is Castle Rock Water's top priority. Castle Rock Water continues to meet or exceed all state and federal drinking water standards.

Castle Rock Water strives to provide clean, safe, great-tasting drinking water to its customers. The Town's water comes from a diversity of sources, including groundwater, surface water, reuse water and imported water. Groundwater is treated at four of our treatment plants. To date, PFAS has not been sampled for in the raw groundwater supply to these plants. Imported water comes already treated from Parker and Aurora. To date, this supply has also not been sampled for PFAS. The Plum Creek Water Purification Facility treats groundwater, surface water and reuse water. PFAS has been detected in the surface water and the reuse water. This water is treated using a multi-barrier process that includes granular activated carbon, which is an approved technique to reduce PFAS levels. (LINK) GAC is one of the best-known methods to remove PFAS; currently, there are only a few treatment plants in Colorado with this process. Read more about GAC systems.

Castle Rock Water is committed to protecting our residents and our resources. Staff have been engaged in numerous discussions at Federal, Regional and State levels (including regulators and legislators) stressing the importance of appropriately regulating, managing and remediating PFAS substances. The multibarrier approach used in our treatment system means we have flexibility in treating new substances.

These communications have included the importance of holding those parties who introduced the PFAS into the environment responsible for remediation and clean-up and the importance of prohibiting additional use of PFAS compounds in the manufacture of goods.

In 2022, Colorado Governor Jared Polis signed into law the most comprehensive state bill restricting the sale of PFAS in consumer products, as well as fluids used in the extraction of oil and gas products, as early as 2024. Eliminating PFAS at the source is the best way to keep it out of the environment.

We also support a growing body of peer-reviewed scientific research on PFAS. As a leader in the water industry, Castle Rock Water is engaged in stakeholder and other local, state and national opportunities to develop solutions. Castle Rock Water will continue to closely monitor the EPA's guidelines on PFAS to inform our next steps.

Drinking water providers test their product more than just about any other industry. Water quality is highly regulated, primarily through CDPHE, which is the enforcement of the Environmental Protection Agency's (EPA's) Safe Drinking Water Act and Clean Water Act. Measuring PFAS in water is easier compared to measuring exposure from other sources of PFAS like clothing, food packaging or dental floss.

Bottled water is not regulated nor tested to the same stringent standards as tap water and bottled water quality can vary. According to Consumer Reports, some bottled water may also contain PFAS. The EPA is not recommending bottled water as a source to avoid PFAS. Various organizations are beginning to look deeper into this topic. Find more about PFAS and bottled water from the American Water Works Association.

We encourage residents to avoid PFAS when purchasing consumer goods and new household products. This will not only protect your health but also prevent the compounds from further entering our environment. For a list of PFAS-free consumer goods, visit PFAS Central.

Generally, it is more effective to treat water system-wide where it can be managed by trained, licensed water treatment professionals and supported through state-of-the-art laboratories. If you do use a filter, for example with your refrigerator's water or ice dispenser, please make sure that you replace the filter regularly based on the manufacturer's recommendation.

Surrounding communities have received reports of companies using predatory sales tactics to scare customers into paying more than they need to on water treatment options. Expensive water filtration systems are absolutely not necessary for anyone with Castle Rock water.