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

The City of Tigard maintains almost 300 miles of water distribution mains throughout the Tigard Water Service Area (TWSA). Connecting this water mains to individual customers is the water service line. A service line is defined as the pipe(s), fittings, and meter located between the water main and a customer's building inlet.

In the TWSA, the segment of service line between the water main and water meter is owned and maintained by the City of Tigard, and the segment of service line between the water meter and building entrance is owned and maintained by the customer. Water service lines can be made of different materials, including plastic, galvanized steel, cooper, or lead.

The City of Tigard manages an ongoing Water Service Inventory project throughout the Tigard Water Service Area as part of a protective effort to confirm that there are no lead materials in use in our water system. This project meets neew federal requirements set forth in the US Environmental Protection Agency Lead and Cooper Rule Revisions to identify service lind materials in water systems by October 2024. Identifying lead service lines and replacing them, if found, is important to protecting public health.

To create this inventory, the City of Tigard Water Department used the following resources and methods to determine that all services lines within the Tigard Water Service area non-lead:

• 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.

Since the probability of finding lead service lines was already very low because of regional construction practices and prior lead bans, Tigard's approach was designed to be cost-effective and efficient with minimal impact on customers. Tigard has completed its water service line inventory and has confirmed that there are no lead service lines within the Tigard Water Service Area.

Where Does Tigard's Water Come from?

In 2024, Tigard's drinking water system delivered water from the Lake Oswego-Tigard Water Treatment plant with a supplemental supply from groundwater wells.

• 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.

How is your drinking water treated?

The Lake Oswego-Tigard Treatment Plant uses a conventional treatment process which includes ballasted flocculation, intermediate ozone, and biological filtration.

• 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.

TWSA Source Water Assessment

In 2005, the Oregon Health Authority and the Department of Environmental Quality conducted a source water assessment for the aquifer storage and recovery wells and the native graoundwater well serving the Tigard Water Service Area (TWSA). In 2019, the report was evaluated and updated in conjunction with other Clackamas River water providers. The purpose of the assessment was tto identify potential sources of direct and indirect contamination in areas surrounding our wells. To view the reports, contact Environmental Program Coordinator at 503-718-2599.

What the EPA Says About Drinking Water Contaminants

In order to ensure that tap water is safe to drink, the US Environmental Protection Agency (EPA) set regulatory limits on the amounts of certain contaminants in water provided by public water systems. The Food and Drug Administration (FDA) sets limits on contaminants in bottled water, which must provide the same protection for public health.

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 disolves naturally ocurring minerals and, in some cases, radioactive material, can pick up substances resulting from the presence of animals or from human activity.

Drinking water, including bottled water, may contain small amounts od some contaminants. However, the presence of contaminants does not necessarily indicate that the water poses a health risk.

Contaminants

Contaminants that may be present in source water include:

• 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.

More information about contaminants and potential health effects is available from the EPA Safe Drinking Water Hotline 800-426-4791.

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.