Seattle area · Water quality guide

Lead in Seattle's tap water

Seattle's source water is some of the cleanest in the country — lead almost never comes from the supply. When it shows up at your tap, it comes from your own home's plumbing. Here's how that happens, who's most at risk, and how to find out what's actually in your water.

Where lead actually comes from

The Cedar River and Tolt watersheds deliver water with virtually no lead in it. The problem is the last few feet: the service line connecting your home to the main, the solder joints in your pipes, and older brass fixtures. Water sitting in that plumbing overnight can pick up small amounts of lead before it ever reaches your glass.

Why the age of your home matters

Lead solder wasn't banned in U.S. plumbing until 1986. Homes built or re-plumbed before then are the most likely to have lead-bearing joints or fixtures, and Seattle still has thousands of older lead service lines in the ground. The EPA's action level is 15 ppb — but the agency is clear that there is no known safe level of lead exposure, which is why testing beats guessing.

3,400+
Lead service lines in Seattle as of 2023
1986
Year lead solder was banned in plumbing
15 ppb
EPA lead action level — no level is truly “safe”

How to know what's in your water

City-wide averages can't tell you what's coming out of your kitchen tap, because the lead is added by your home, not the supply. The only way to know is a first-flush test: you collect the very first water of the morning — after it's been sitting in your pipes overnight — and a certified lab measures exactly what leached in. That's the number that matters.

What you can do about it

If your test shows elevated lead, the fix is straightforward and doesn't require re-plumbing your house. A reverse-osmosis system at the kitchen tap removes lead from the water you drink and cook with, and we size the system to your actual results rather than selling you more than you need.

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