Seattle Public Utilities, WA
Lead detected, under the action levels
Latest 90th-percentile lead: 1.6 ppb (monitoring period 2025-2025). The federal action level is 15 ppb today and drops to 10 ppb in Nov 2027; EPA's health goal is 0. Lead was measured in sampled homes but the 90th percentile is under both action levels. EPA's health goal for lead is zero, so test your own tap if your home was built before 1986 or anyone in it is pregnant or a young child.
Who runs the water here
Seattle Public Utilities serves about 1,161,961 people through 195,204 service connections, which makes it a very large system under EPA's size classes. It is owned by a local government (city, town, county or district) and draws surface water, in King County, Washington. EPA system ID: WA5377050. Ask the utility on your bill for your address in their service line inventory.
Lead results over time
That is down 1.9 ppb from 3.5 ppb in the period ending 2024. The highest 90th-percentile result EPA holds for Seattle Public Utilities is 4.1 ppb across 10 monitoring periods, none of them over 15 ppb.
| Period ending | 90th-percentile lead |
|---|---|
| 2025 | 1.6 ppb |
| 2024 | 3.5 ppb |
| 2023 | 3.5 ppb |
| 2022 | 2.8 ppb |
| 2021 | 2.2 ppb |
| 2020 | 4 ppb |
| 2019 | 1.9 ppb |
| 2018 | 1.6 ppb |
| 2017 | 4.1 ppb |
| 2016 | 3.1 ppb |
How Seattle Public Utilities compares
Of the 2,218 Washington systems with a lead result, the median latest reading is 1 ppb; 18 are over 15 ppb right now and 62 have gone over at some point. Seattle Public Utilities's 1.6 ppb sits at the 63rd percentile in Washington and the 65th nationally (higher means more lead).
Neighbouring systems
153 other systems share King County; 48 of them have a higher latest lead result than Seattle Public Utilities. If you are unsure which one supplies your house, the name on your water bill decides it.
| System | People | Latest lead |
|---|---|---|
| Bellevue City Of | 321,349 | - |
| Kent Water Department | 166,421 | 0 (not detected) |
| Redmond Water System City Of | 163,335 | 2 ppb |
| Lakehaven Water And Sewer District | 148,809 | 3.3 ppb |
| Renton City Of | 108,091 | 1.9 ppb |
| Auburn City Of | 107,655 | 2.2 ppb |
| Highline Water District | 100,170 | 1.4 ppb |
| Northshore Utility District | 99,789 | - |
| Sammamish Plateau Water & Sewer | 79,362 | 1.7 ppb |
| Soos Creek Water & Sewer District | 74,172 | - |
Your move
Test your own tap with a certified lab first-draw sample; Seattle, WA may offer free or low-cost kits through the utility. If your own line is lead, replacing the private side runs about $1,200-$12,300 (EPA average about $4,700). Ask Seattle Public Utilities whether it covers that cost before hiring anyone - many utilities now do.
These figures describe homes the utility sampled, not your tap. Only your service line record or a test of your own water answers the question for your house. Why sampled homes are the worst-case ones is in the guide to reading the number. The action level is dropping - the 10 ppb rule from 2027.