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Water Quality

Washington State Department of Health (DOH) regulates the water testing requirements for all the District’s water systems. Group A water systems have 20-40 water quality samples taken each year while Group B water systems have 2-3 samples taken annually. DOH has the Source Water Assessment Program (SWAP) data available online at http://www.doh.wa.gov/ehp/dw/sw/assessment.htm which lists potential contamination for each Group A water source in the state. More information about specific contaminants and potential health effects can be obtained by calling the EPA’s Safe Drinking Water Hotline 1-800-426-4791 or visiting their website at www.epa.gov/drink/contaminants/.

Water Quality Testing

The routine contaminants the District tests for in the various water systems are:

  • Coliform – total coliform, fecal coliform and E. coli (monthly for Group A and twice a year for Group B)
  • Nitrate (annually for Group A and every 3 years for Group B)
  • Copper (every 3 years for Group A community and non-community non-transient systems)
  • Lead (every 3 years for Group A community and non-community non-transient systems)
  • Iron (secondary contaminant)
  • Manganese (secondary contaminant)
  • Chloride (secondary contaminant)

For systems treated with chlorine we also test for disinfection byproducts that may be produced by the chlorine:

  • Total trihalomethanes
  • Haloacetic acids

Other contaminants we occasionally test for when required by DOH:

  • Synthetic organics – pesticides, herbicides, insecticides
  • Volatile organic chemicals
  • Radioactive contaminants
  • Asbestos for systems with asbestos concrete pipes
  • Other inorganic contaminants not part of the routine testing

Sampling Waivers

Waivers mean no testing of a specified contaminant is required for a set period of time and are available for the occasionally tested contaminants. Waivers may be granted to Group A water system by the State based on susceptibility assessment of the source or automatically granted for state-wide waivers. The Consumer Confidence Reports lists the waivers the water system has been granted, and the reports are provided below.

Definitions for Water Quality

  • Action Level – the concentration of a contaminant which, if exceeded, triggers treatment or other requirements which a water system must follow.
  • Maximum Contaminant Level (MCL) – the highest level of a contaminant that is allowed in drinking water. MCLs are set as close to the maximum contaminant level goal as feasible using the best available treatment technology. To understand the possible health effects described for many regulated contaminants, a person would have to drink 2 liters of water every day at the MCL for a lifetime to have a one-in-a-million chance of having the described health effect.
  • Maximum Contaminant Level Goal (MCLG) – the level of a contaminant in drinking water below which there is no known or expected risk to health. MCLGs allow for a margin of safety.
  • Nephelometric Turbidity Unit (NTU) – a measure of the clarity of water. Turbidity in excess of 5 NTU is just noticeable to the average person.
  • Non-Detects (ND) – laboratory analysis indicates the contaminant is not present or not detected in the water sample.
  • Parts per Billion (ppb) = micrograms per liter (μg/l) – one part per billion.
  • Parts per Million (ppm) = milligrams per liter (mg/l) – one part per million corresponds to one minute in two years or a single penny in $10,000.
  • Secondary Maximum Contaminant Level (SMCL) – these standards are developed to protect the aesthetic qualities of drinking water and are not health based.
  • Treatment Technique (TT) – a required process intended to reduce the level of a contaminant in drinking water.

Consumer Confidence Reports

Consumer Confidence Reports are available for all Group A community systems and most Group A non-community systems. These reports are updated annually by July 1. Postcards with direct URLs (weblinks) are mailed to customers before July 1 except for those who have requested paper copies. If you would like to receive a paper copy instead of the URL, please contact the Director of Operations-Water to be placed on the paper copy mailing list. Below are links to the most recent Consumer Confidence Reports. If you would like copies of past reports, please make a public records request.