2025 Water Quality Report
2025 ANNUAL
FOR CUSTOMERS OF ASOTIN COUNTY PUD — MAY 2026
DEVOTED TO WATER QUALITY
ASOTIN COUNTY PUD is pleased to report that your drinking water safely complies with state and federal drinking water quality standards. This annual report summarizes the key findings of the Asotin PUD water quality testing program which demonstrates our commitment to a clean, safe and reliable supply of drinking water.
All information contained in this report has been collected and reported in accordance with water quality standards established by the United States Environmental Protection Agency (EPA) and the Washington State Department of Health (DOH). This report provides you with details about where your water comes from, what’s in it, and how safe it
WATER QUALITY SAMPLING AND TESTING
At the Asotin PUD, ensuring the safety of your water is the most important thing we do. The PUD collects water samples weekly for bacteriological testing from various points throughout the water system. The number of samples taken depends on the size of the population served by the water system. Bacteria are microbial substances that are naturally present in the environment and those produced by humans and animals.
All of the bacteriological water samples taken in 2025 met or exceeded state and federal drinking water standards.
In addition, state and federal regulatory agencies require testing for inorganic substances, disinfection by products and man-made compounds such as pesticides and petroleum additives. All samples collected are submitted to Washington State certified independent laboratories for analysis. Of the multitude of state and federal regulated water quality contaminants tested over the past several years only a few showed detectable levels and each was below the EPA mandated Maximum Contaminant Level (MCL). The table inside provides the results from water quality testing.
WHERE DOES YOUR WATER COME FROM?
The PUD relies on groundwater from the Lewiston Basin Aquifer to supply water to your home. This deep aquifer spans the Lewiston-Clarkston valley forming at the Craig and Blue Mountains extending to the base of the Lewiston-Clarkston hill and east to west from Lapwai, Idaho to the base of Alpowa Grade located in Asotin County, Washington.
Water is pumped from the aquifer by PUD wells into approximately 125 miles of distribution line and delivered to your home ready for use on demand.
This on-demand system operates based upon the level of our seven water storage reservoirs, which have the capacity of 9.88 million gallons. When a reservoir reaches a certain level our automated control system tells the pump to run and water begins to flow.
When water is pumped from the aquifer by a PUD well, chlorine is added as a disinfectant to ensure that the water is free of harmful microorganisms. The PUD has a system in place to generate chlorine on-site at four of seven primary water supply
In 1989, the PUD was instrumental in obtaining Sole or Principal Source Aquifer designation as provided for in the Safe Drinking Water Act of 1974.
This designation protects the aquifer from potential contamination by mandating that the EPA review any federal projects that would compromise the aquifer.
WHO REGULATES WATER QUALITY?
The sources of drinking water (both tap water and bottled water) include rivers, lakes, streams, ponds, reservoirs, springs and wells. As water travels over the surface of the land or through the ground, it dissolves naturally occurring minerals and radioactive material and can pick up substances from the presence of animals or from human activity.
To ensure that tap water is safe to drink, the Environmental Protection Agency (EPA) prescribes limits on the amount of certain substances in water provided by public water systems. U.S. Food and Drug Administration (FDA) regulations establish limits for substances in bottled water.
Drinking water, including bottled water may reasonably be expected to contain at least small amounts of some contaminants. The presence of contaminants does not necessarily indicate that the water poses a health risk.
More information about contaminants and potential health effects can be obtained by calling the EPA’s Safe Drinking Water Hotline. (800-426-4791)
Some people may be more vulnerable to contaminants in drinking water than the general population. Immuno-compromised persons — such as persons with cancer undergoing chemotherapy, persons who have undergone organ transplants, people with HIV/AIDS or other immune system disorders, some elderly, and infants— can be particularly at risk from infections. These people should seek advice about drinking water from their health care providers. EPA and/or Center for Disease Control (CDC) guidelines on appropriate means to lessen risk of infection by cryptosporidium and other microbial contaminants are available from the EPA’s Safe Drinking Water Hotline at (1-800-426-4791)
| Contaminants that may be present in source water include: | Possible source |
|---|---|
| Microbial contaminants such as viruses and bacteria | Sewage treatment plants, septic systems, agricultural livestock operations, and wildlife |
| Inorganic contaminants such as salts and metals | Naturally occurring or result from urban storm water runoff, industrial or domestic wastewater discharges, oil and gas production, mining or farming |
| Pesticides and herbicides | A variety of sources such as agriculture, storm water runoff, and residential uses |
| Organic chemical contaminants, including synthetic and volatile organics | By-products of industrial processes and petroleum production; can be from gas stations, urban storm water runoff, septic systems |
| Radioactive contaminants | Naturally occurring or the result of oil and gas production and mining activities |
ANNUAL WATER QUALITY REPORT for the YEAR 2025
Listed in the table below are the compounds that were detected in the PUD drinking water supply.
Definitions of Terms Used
Disinfection Byproducts: Trihalomethanes (TTHMs) form as by-products of the chlorination process that is used to kill or inactivate disease-causing microbes. Haloacetic Acids (HAA) are disinfection by-products monitored to determine compliance with EPA ‘s Disinfection By-products Rule.
EPA Allowable Limit or Maximum Contaminant Level (MCL): The highest level of contaminant allowed in drinking water.
EPA Ideal Goal or Maximum Contaminant Level Goal (MCLG): The level of contaminant in drinking water below which there is no known or expected health risk.
Levels in PUD Water: The highest level of compound detected in the PUD water supply. ND = No detection of substance. Year Tested: Indicates the most recent year that a compound was tested. The state requires certain contaminants to be monitored less than once per year because concentrations do not vary significantly from year to year. Testing occurs between Jan. 1 and Dec. 31st.
Source of Compound: The common source of the compounds detected.
Complies?: A “Yes” indicates that the range detected is within EPA allowable limits. A “No” would require an Action Level (AL), the concentration of a contaminant which, if exceeded, triggers treatment or other requirements a water system must follow.
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Parts Per Million/Parts Per Billion/Parts per Trillion (PPM/PPB/PPT)): Units describing the levels of detected contaminants.
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Picocuries per liter (pCi/L): This is a measure of radiation for radionuclide testing.
| Inorganic Substances | EPA Allowable Limit (MCL) | EPA Ideal Goal (MCLG) | Levels in PUD Water | Year Tested | Source | Complies? |
|---|---|---|---|---|---|---|
| Nitrate (ppm) | 10.0 | 10.0 | .89 | 2025 | Erosion of natural & man-made deposits | Yes |
| Fluoride (ppm) | 4.0 | 4.0 | .982 | 2020 | Erosion of natural deposits | Yes |
| Arsenic (ppb) | 10.0 | 0 | 1.99 | 2020 | Erosion of natural deposits | Yes |
| Radionuclides | ||||||
| Radium (pCi/L) | 5.0 | 0 | .526 | 2024 | Decay of natural & man-made deposits | Yes |
| Gross Alpha (pCi/L) | 15.0 | 0 | .753 | 2024 | Erosion of natural deposits | Yes |
| Disinfection Byproduct | ||||||
| Total Trihalomethanes (TTHMs) (ppb) * | 80.0 | 0 | 4.66 | 2025 | By-product of chlorination | Yes |
| Haloacetic Acids (HAA) (ppb) * | 60.0 | 0 | ND | 2025 | By-product of chlorination | Yes |
| Chlorine Residual (ppm) | 4.0 | 4.0 | .60 | Range Detected .50—.70 | Measure of disinfectant added to water | Yes |
| Lead & Copper | EPA (MCL) | EPA (MCLG) | Exceeds (AL) | Year Tested | Source | Complies? |
| Lead (ppb) | 15.0 | 0 | None | 2023 | Corrosion of household plumbing | Yes |
| Copper (ppm) | 1.3 | 1.3 | None | 2023 | Corrosion of household plumbing | Yes |
| Volatile Organic PFAS | EPA (MCL) | EPA (MCLG) | Levels | Year Tested | Source | Complies? |
| PFOA (ppt) | 4.0 | 0 | 3.05 | 2025 | Man-made Chemical | Yes |
Lead in Drinking Water: If present, elevated levels of lead can cause serious health problems, especially for pregnant women and young children. Lead in drinking water is primarily from materials and components associated with service lines and home plumbing. The Asotin County PUD is responsible for providing high quality drinking water, but cannot control the variety of materials used in plumbing components. When your water has been sitting for several hours, you can minimize the potential for lead exposure by flushing your tap for thirty seconds to two minutes before using water for drinking or cooking. If you are concerned about lead in your water, you may wish to have your water tested. Information on lead in drinking water, testing methods, and steps you can take to minimize exposure is available from the Safe Drinking Water Hotline or at http://www.epa.gov/safewater/lead. (See table for test results)
ASOTIN COUNTY PUD —ANNUAL WATER QUALITY REPORT for the YEAR 2025
CUSTOMER PARTICIPATION ENCOURAGED
ASOTIN COUNTY PUD is a consumer-owned public utility. We welcome your views and encourage your participation in the decision-making process. The Board of Commissioners meet at 5:30 pm on the second and fourth Tuesday of each month at the PUD office located at 1500 Scenic Way, Clarkston, WA.
We are THE source of Water Quality information for Asotin County PUD Customers
We would be happy to answer any questions you may have regarding this WATER QUALITY REPORT
Call us at 509-758-1010.
You can visit the PUD on the web at: www.asotinpud.org
Commissioners
Judy Ridge, President Greg McCall, Vice President Don Nuxoll, Secretary
Manager
Tim Simpson
509-758-1010
Monday through Friday
7:30 AM to 4:30 PM
Staff on-call 24 hours a day
PO Box 605
1500 Scenic Way
Clarkston, WA 99403-0605
PWS ID: 93343E