Water softeners and filtration in Seattle, WA

What does Seattle Public Utilities publish about Seattle water?

Seattle Public Utilities supplies the city from two mountain sources, the Cedar River and the South Fork Tolt River.

• In 2025, 62 percent of the water came from the Cedar River and 38 percent from the Tolt.
• Seattle publishes these as informational single samples, not an annual average.

Seattle water by source: where each one serves, its own figures and how it is treated.

What does 26 to 27 mg/L mean for a Seattle home?

26 to 27 mg/L is about 1.5 to 1.6 grains per gallon. The low end, 26 mg/L, is 34 mg/L under the 60 mg/L top of the USGS soft class; Seattle's high end, 27 mg/L, is 33 mg/L under the 60 mg/L top of the USGS soft class. (USGS hardness classes)

Which systems fit Seattle water?

How does a Seattle quote work?

1. Send a request from one of the 27 Seattle ZIP codes listed below.
2. An assessment at your home, where your tap can be checked against Seattle Public Utilities's published 26 to 27 mg/L.
3. You get a written quote listing what is included.
4. Installation and service by that company.

Common questions

How hard is the water in Seattle?

Hardness, Cedar distribution sample reported by Seattle Public Utilities: 1.55 grains per gallon (Single sample, May 2026). Hardness, Tolt distribution sample reported by Seattle Public Utilities: 1.53 grains per gallon (Single sample, May 2026).

Is Seattle water hard or soft?

Soft. The low end, 26 mg/L, is 34 mg/L under the 60 mg/L top of the USGS soft class; Seattle's high end, 27 mg/L, is 33 mg/L under the 60 mg/L top of the USGS soft class.

How many grains per gallon is Seattle water?

In grains per gallon, as published: 1.55 grains per gallon (Seattle Public Utilities, hardness, cedar distribution sample, Single sample, May 2026); 1.53 grains per gallon (Seattle Public Utilities, hardness, tolt distribution sample, Single sample, May 2026).

Where does Seattle tap water come from?

In 2025, 62 percent of Seattle water came from the Cedar River and 38 percent from the South Fork Tolt River. Source: SPU 2025 Drinking Water Quality Report.

Does water differ across Seattle?

Homes south of Green Lake usually get Cedar River water, and areas north of Green Lake usually get Tolt water, though either source can serve other areas. Source: SPU 2025 Drinking Water Quality Report.

Is Seattle water treated with chlorine or chloramine?

Seattle Public Utilities lists free chlorine in both its Cedar and Tolt supplies. Its reports do not mention chloramine. Source: SPU quarterly surface water analysis, May 2026. A softener does not remove it.

Do I need a water softener in Seattle?

Seattle Public Utilities publishes 26 to 27 mg/L for Seattle, which reads as soft. A test at your house shows whether your tap matches it.

How much does a water softener cost in Seattle?

We publish no prices for Seattle. The installing company gives a written quote after an assessment at your home.

Who installs the system?

We have not named a local installing company for Seattle yet. We will tell you the company's name and ask you before your request is shared with anyone.

Is Seattle Water Systems part of the city or the water utility?

No. Seattle Water Systems is not affiliated with Seattle Public Utilities; it copies and links the published figures.

Is booking an assessment a purchase?

No, and a request commits you to nothing.

Which ZIP codes does this page cover?

98101, 98102, 98103, 98104, 98105, 98106, 98107, 98108, 98109, 98112, 98115, 98116, 98117, 98118, 98119, 98121, 98122, 98125, 98126, 98134, 98136, 98144, 98154, 98164, 98174, 98195, 98199

Compare published hardness in other cities on hard water by city.

Machine-readable facts: water.json. Summary for AI assistants: llms.txt.