Water Quality Report
Redmond's most current Water Quality Report provides detailed reporting on Redmond's water and its latest lead and copper testing.
Where does my drinking water come from?
Redmond is part of the Cascade Water Alliance (CWA) and buys more than 65% of its supply from the Seattle Tolt River supply through the CWA. The rest of our drinking water supply comes from our five wells that serve the areas of town east of the Sammamish River.
Drinking Water Quality
The City of Redmond believes that safe drinking water is no accident - it is our highest priority. But we need your help to continue to be successful.
Redmond's Wellhead Protection Ordinance was a major step toward protecting approximately 35% of our City’s drinking water supply which comes from shallow well aquifers. Take a few minutes to learn how the Ordinance helps to protect our drinking water supply by visiting the Groundwater/Wellhead Protection on this website.
All of Redmond's water supply meets or exceeds all Environmental Protection Agency and Washington State Department of Health drinking water regulations. Water from each well is treated before it enters the City water supply system. Currently, Redmond provides three types of treatments - fluoridation, chlorination, and pH adjustment - to comply with these regulations.
- Redmond’s water is safe to drink.
- Redmond is part of the Cascade Water Alliance (Cascade), and roughly 65% of its supply comes from the Seattle Tolt River supply through Cascade. The rest of our drinking water supply comes from our five wells that serve the areas of town east of the Sammamish River.
- The Environmental Working Group (EWG) issued a report today, based on an analysis of federal data from nationwide drinking water tests, that says the chemical compound Hexavalent chromium (chromium(VI), Cr(VI), chromium 6) has been detected in “water supplies for more than 200 million Americans in all 50 states.”
- Chromium-6 is an unregulated compound under U.S. Environmental Protection Agency (EPA) rules.
- The compound occurs naturally in the environment from the erosion of natural chromium deposits. It can also be produced by industrial processes. There are demonstrated instances of chromium being released to the environment by leakage, poor storage, or inadequate industrial waste disposal practices, however to our knowledge, the chromium 6 found in Redmond’s drinking water is not related to a man-made source. There is no regulatory limit for the compound in Washington State.
- The City of Redmond and Seattle Public Utilities (SPU) tested for chromium-6 in their water last year, and the results are contained in Redmond’s 2016 Water Quality Report (Page 5).
- Redmond detected chromium-6 in both our wholesale and well water supplies. Levels ranged from not detected to 0.44 parts per billion (ppb).
- In California, where chromium-6 is regulated, the regulatory level is 10 ppb—25 times the amount detected in Redmond’s water.
- Redmond plans to continue monitoring levels of chromium-6 in our drinking water supplies.
- For further information about the health risks of chromium-6, please contact the Washington State Department of Health, Office of Water Quality, 360-236-3162 and the U.S. Environmental Protection Agency (Region 10), at 206-553-2160.
Cascading Water & Fresh Air Improves our Water
They look like small plastic Wiffle balls, and there are thousands of them stacked inside new water aeration towers in Redmond. The water cascades down through the plastic balls, which break up the water into small droplets, so the extra carbon dioxide (CO2) can escape the water. Air is blown up the tower to further help get rid of the extra CO2 and keep filling the tower with fresh air. All this action aerates the water and raises its pH level, which helps to protect your household plumbing and the City's water mains.
The City operates five wells, which supply about 35 percent of the water used in Redmond's service area. Redmond's well water has a moderately high alkalinity level and much of that comes from dissolved carbon dioxide (CO2), which can corrode metal pipes. Rainwater that percolates down through the ground to replenish wells absorbs CO2 from microbes in the soil.
The new aeration technology removes about 90 percent of the dissolved CO2 in the well water without the use of chemicals. The current method used to raise the pH is to inject caustic soda into well water, at a cost of about $200,000 a year. Caustic soda is used by many drinking water municipalities to effectively adjust pH, but there are drawbacks to its use. It is hazardous for operators to handle safely, can cause water system equipment to wear out faster and can cause calcium carbonate to build-up on the inside of water mains, which slowly makes the pipe diameter smaller and restricts water flow.
The new towers are part of the water treatment processes for Wells 1 and 2, Well 3, and Well 5. Wells 1 and 2 are located in Anderson Park, while Well 3 is located along Avondale Road, and Well 5 is near the Target and Home Depot stores.
Questions about the above new water aeration towers:
Contact: Jeff Thompson - 425-556-2884