Annual Water Quality Report – 2021

North City Water District continues to maintain state and federal water quality guidelines that are significantly below EPA maximum levels.

All About Your Water

Where Is Your Water From?
Tolt and Cedar River Watersheds.

Who Tests Your Water?
Your drinking water is regulated by the Environmental Protection Agency (EPA), who sets drinking water quality standards, establishes testing methods and monitoring requirements for water utilities, sets maximum levels for water contaminants, and requires utilities to give public notice whenever a violation occurs. Your drinking water is tested frequently both by North City Water District and Seattle Public Utilities, our supplier, to ensure that high quality water is delivered to your home and business.

How Safe is Your Water?
Your water falls safely within state and federal guidelines for each and every contaminant, significantly below the EPA’s levels.

What is Your Water Being Tested For?
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 water poses a health risk. More information about contaminants and potential health effects is available by calling the Environmental Protection Agency’s (EPA) Safe Drinking Water Hotline 800.426.4791.

When is Your Water Tested?
Out of roughly 100 EPA-regulated contaminants, some parameters are tested continuously, some are tested daily, some are tested weekly, some monthly, some quarterly, and some annually—all in accordance with federal and state regulations. Others, such as UCMR monitoring or herbicides, are only required to be tested once every 6 years.

How is Your Water Tested?
Over 200 compounds are tested and not detected; most of this monitoring occurs once every several years. Tests are done before and after treatment and while your water is in the distribution system. The Tables presented on the following page list all of the contaminants detected in the most recent required water testing and compare them to the limits and goals set by the EPA and the State of Washington to ensure your tap water is safe. Not shown are more than 200 additional contaminants that were tested for, but not detected, in your drinking water.

If you would like to see a list of these other compounds or if you have other water quality questions, do not hesitate to contact us at 206.362.8100. Note: asbestos monitoring is not required for our District because all asbestos pipe in our distribution system was replaced prior to 1991.

Click on the below tables to enlarge for better viewing:

Lead and Copper Monitoring Results

Our regional water supply does not contain lead or copper. However it is possible that lead levels at your home may be higher than at other homes in the community as a result of materials used in your home’s plumbing.

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. North City Water District 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 30 seconds to 2 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 at 1.800.426.4791 or at

People With Special Concerns

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/Centers for Disease Control (CDC) guidelines on appropriate means to lessen the risk of infection by microbial contaminants are available from the Safe Drinking Water Hotline at 1.800.426.4791.

If you would like to learn more about your water, or if you have questions about its quality, please don’t hesitate to contact North City Water District at 206.362.8100.

Additional Water Monitoring

North City Water District monitors the water in our distribution system for various compounds according to UCMR4 standards, as well as other parameters that can be impacted by algae. Our primary source water is from the Tolt River but we do also get water from the Cedar River, both of which can experience naturally occurring, seasonal algae blooms.

Typically these blooms occur in the late spring, but due to a number of environmental factors including sunlight and temperature, blooms can occur at other times of the year. Although the algae we see in our water supplies is not associated with health concerns, it can create tastes and odors. Thankfully these are well controlled at both treatment facilities. Please contact us at our office if you would like to receive a copy of these results.

More About 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, in some cases, radioactive material, and can pick up substances resulting from the presence of animals or from human activity. In Seattle’s surface water supplies, the potential sources of contamination include:

  • Microbial contaminants, such as viruses, bacteria, and protozoa from wildlife;
  • Inorganic contaminants, such as salts and metals, which are naturally occurring; and
  • Organic contaminants, which result from chlorine combining with the naturally occurring organic matter.

In order to ensure tap water is safe to drink, the Environmental Protection Agency and/or the Washington state board of health prescribes regulations that limit the amount of certain contaminants in water provided by public water systems. Food and Drug Administration and/or the Washington state department of agriculture regulations establish limits for contaminants in bottled water that must provide the same protection for public health.

We at North City Water District encourage public interest and participation in the decisions that affect our drinking water. If you would like to learn more about our water, have questions about its quality, or would like to know what you can do to help keep our water supply clean, safe and abundant, please don’t hesitate to contact us at 206.362.8100.

You are also welcome to participate in our Board of Commissioners meetings, which take place every first and third Tuesday of each month at 3:00 pm. Until COVID restrictions are lifted, you can join these meetings by dialing into our conference call. The call-in number is listed on each meeting agenda; agendas are located in the “Information” section of our website.

Additional organizations for information about your water include:

Seattle Public Utilities
Phone: 206.684.3000

United States Environmental Protection Agency (EPA) and the Safe Drinking Water Hotline
Phone: 800.426.4791

Washington State Department of Health (DOH):
Phone: 800.521.0323