2024 Annual Water Quality Report
Overview of the Safe Drinking Water Act
The Safe Drinking Water Act (SDWA) was originally passed by Congress in 1974 to protect public health by regulating the nation’s public drinking water supply. The law was amended in 1986 and 1996 and requires many actions to protect drinking water and its sources—rivers, lakes, reservoirs, springs, and ground water wells. (SDWA does not regulate private wells which serve fewer than 25 individuals.) SDWA authorizes the United States Environmental Protection Agency (U.S. EPA) to set national health-based standards for drinking water to protect against both naturally-occurring and man-made contaminants that may be found in drinking water.
U.S. EPA, states, and water systems then work together to make sure that these standards are met. Protecting America’s drinking water is a top priority for EPA. EPA has established protective drinking water standards for more than 90 contaminants, including drinking water regulations issued since the 1996 amendments to the Safe Drinking Water Act that strengthen public health protection. Over 92 percent of the population supplied by community water systems receives drinking water that meets all health-based standards all of the time.
Protecting America’s drinking water is a top priority for the U. S. Environmental Protection Agency (EPA). EPA has established protective drinking water standards for more than 90 contaminants, including drinking water regulations issued since the 1996 amendments to the Safe Drinking Water Act that strengthen public health protection. Over 92 percent of the population supplied by community water systems receives drinking water that meets all health-based standards all of the time.
Lead Line Inventory
- Tigard Water Dept. service line material records;
- Oregon State law and plumbing code that do not allow lead as a pipe material;
- Oregon Health Authority determination that service lines with a diameter of two inches or greater are non-lead; and
- Physical inspection of a random selection of service lines within the TWSA that had an unknown pipe material, statistically demonstrating that there are no lead service lines in the TWSA.
- Lake Oswego-Tigard Water Treatment Plant: The Lake Oswego-Tigard Water Treatment Plant withdraws water from the Clackamas River Basin which encompasses nearly 940 square miles. Drawn from the Clackamas River, the pumped water moves through a pipeline buried beneath the Willamed River to the Lake Oswego-Tigard Water Treatment Plant located in West Linn.
- Our other partners: In addition to our partnership with Lake Oswego, Tigard is also a member of the Regional Water Providers Consortium and the Clackamas River Water Providers. The Regional Water Providers Consortium provides leadership in the planning, management, stewardship, and resiliency of drinking water in the Portland metropolitam region. They are comprised of members located in the Clackamas, Columbia, Multnomah, Washington, and Yamhill counties. The Clackamas River Water Providers is a coalition of the municipal water providers that get their drinking water from the Clackamas River who are working together on water resource issues. The purpose of the organization is to fund and coordinate efforts regarding source water protection and public outreach and education around watershed issues, drinking water, and water conservation, so that we can preserve the Clackamas River as a high-quality drinking water source and minimize future drinking water treatment costs while being a good stewards of the river
- Groundwater: During periods of high water demand, Tigard supplements its supply with water from three city-owned aquifer storage and recovery wells, and a native groundwater well. All groundwater sources are disinfected using small amounts of chlorine.
- Ballasted Flocculation uses micro-sand and a coagulant to settle dirt, sediment and contaminants out of the water
- Ozone is then added to remove unpleasant taste and odor compounds and to provide advanced treatment
- Biological Filtration through a deep bed of granular activated carbon and silica sand removes any remaining tiny microbes and contaminants, such as cryptosporidium. Beneficial biological activity removes organic molecules that can produce disinfection byproducts.
- Filtered water is then disinfected using small amounts of chlorine and the pH is adjusted with caustic soda to prevent corrosion of household plumbing.
- Microbial Contaminants, such as viruses and bacteria, which may come from wildlife or septic systems.
- Inorganic Contaminants, such as salts and metals. Can occur naturally or result from urban stormwater runoff, industrial or domestic wastewater discharges or farming.
- Pesticides and Herbicides, may come from a variety of sources, such as farming, urban stormwater runoff, and home or business use.
- Organic Chemical Contaminants, such as syntetic and volatile organic chemicals. These are byproducts of industrila processes, and may come from gas stations, urban stormwater runoff and septic systems.
- Radiactive Contaminants, which can occur naturally.
Your Water is Pure and Safe
The City of Tigard serves over 21,000 individual connections in Tigard, Durham, King City, and unincorporated Washington County, and maintains almost 300 miles of water distribution mains throughout the Tigard Water Service Area.
Tigard is proud of the high quality, reliable water we deliver to customers. Tigard’s water is tested for over 200 contaminants every year, including testing throughout the distribution system. Water distributed to Tigard Water Service Area customers meets or exceeds all water quality standards.
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