Public Water System: Seattle Public Utilities's tap water quality report is the compilation of data collected from federal, state, and local government agencies, most prominently the EPA. We strive to populate the report with the latest data concerning water contaminants, lead and copper levels, and water quality violations. We only collect drinking water data from public water systems.

PWS Service Information
PWS ID: WA5377050
Type: Community water system
EPA Region: 10
Primary Service Area: Residential Area
Primary Source: Surface water
Population Served: 878,000
Contact Information
Wylie Harper
Seattle Public Utilities/WQ Lab
800 S Stacey St
Seattle, WA 98134

This public water system services 30 zip codes in 1 county.

Summary Results

A summary view of the the times a water contaminant was tested and found to exceed the level set by the EPA (the MCL).

We couldn't find any records of contaminants exceeding the regulated limits in your water.

Other Water Contaminants Tested

The following contaminants were tested and within national EPA guidelines.

The last mile of pipe makes a big difference, learn more about testing your water.

We couldn't find any records of contaminants in your water.

Lead and Copper Data

Lead and copper are recorded separately from other contaminants because of the Lead and Copper Rule. As with all other results, these are the findings at the water supply. Lead and copper can be — and often are — added to drinking water in between the water facility and a tap.

Sample ID Contaminant Sampling Start Date Sampling End Date Result
7934528 lead 2016-01-01 2016-12-31 0.0031mg/L
8067693 lead 2016-01-01 2016-12-31 0.0031mg/L
7655083 lead 2015-01-01 2015-12-31 0.004mg/L
7934197 lead 2015-01-01 2015-12-31 0.004mg/L
7167933 lead 2014-01-01 2014-12-31 0.0035mg/L
7755094 lead 2014-01-01 2014-12-31 0.0035mg/L
6893295 lead 2013-01-01 2013-12-31 0.003mg/L
7654768 lead 2013-01-01 2013-12-31 0.003mg/L
6893294 lead 2012-01-01 2012-12-31 0.0036mg/L
7169949 lead 2012-01-01 2012-12-31 0.0036mg/L
5459919 lead 2009-01-01 2009-12-31 0.0058mg/L
4910910 lead 2008-01-01 2008-12-31 0.0144mg/L
5510711 lead 0000-00-00 0000-00-00 0.0058mg/L
5510712 lead 0000-00-00 0000-00-00 0.0051mg/L
5510713 lead 0000-00-00 0000-00-00 0.0066mg/L
5825036 lead 0000-00-00 0000-00-00 0.0051mg/L
6418446 lead 0000-00-00 0000-00-00 0.0066mg/L


Known violations of the Safe Drinking Water Act as recorded by the EPA.

Compliance Dates Rule Violation Type Contaminant Name Status
2015-12-01 - 2015-12-31 Long Term 2 Enhanced Surface Water Treatment Rule Treatment Technique (SWTR and GWR) Long Term 2 Enhanced Surface Water Treatment Rule Returned to Compliance
2007-01-01 - 2007-12-31 Nitrates Monitoring, Regular Nitrate Returned to Compliance
1995-01-01 - 2001-02-01 Lead and Copper Rule OCCT/SOWT Treatment Installation/Demonstration Lead and Copper Rule Known
1979-10-01 - 1979-10-31 Radionuclides Monitoring, Regular Gross Alpha, Excl. Radon and U Known

What My Water Data Means

Water data isn't always easy to interpret, but by following the links on this page you should be able to have most of your questions answered. By clicking the name of a water contaminant or secondary substance you can learn about that specific substance. Ultimately this page should give you some insight towards learning if your water is safe, what water filter you should buy (if any), and how well your local water compares against other sources.


The origin of's water data is explained on our Data Sources page.

Why Is My Water Data Not More Recent?

The recency of the data for your ZIP code depends on the last your water source was tested, by a federal, state, or local agency. More information about the timing can be determined by learning about the dataset in question and seeing how often the EPA (other another governing body) mandated testing.