King County OKs rainwater as sole drinking water source

July 26, 2011

By Warren Kagarise

King County residents can now rely on cloudbursts as a thirst quencher.

On July 21, the county Board of Health approved a measure to allow rainwater captured from roofs as the sole residential water source for single-family homes on septic systems. Under older rules, rainwater could only be used as a supplemental source.

The board acted in response to residents interested in building eco-conscious homes.

Kathy Lambert, a board member and Issaquah’s representative on the King County Council, proposed adding rainwater-catchment systems as a tool for another water source.

“Extending public water lines or digging a well are not always available or feasible in rural and rugged areas of King County, or they can be so expensive to install that they render a lot unbuildable,” she said in a statement. “The ability to utilize rainwater will be a particular advantage in mountainous areas of the county with terrain and soil conditions that make it difficult to site a well and on-site sewage system that do not interfere with each other.”

The code change follows recent action by the state Department of Ecology to remove permit requirements for rainwater harvesting.

“Roof-top rainwater collection systems could be a good solution for homeowners who want to maximize water conservation,” Larry Fay, manager of community environmental health at Public Health – Seattle & King County, said in a statement. “These systems require close attention to water use management, so they aren’t right for everybody, but I’m pleased it’s now an option for single family homeowners.”

Public Health – Seattle & King County rules started to allow rainwater as a drinking water source last year, but only as a supplement to public water, a well or a spring.

Now, single-family homes on septic systems can use rainwater for all uses, albeit under certain conditions.

The regulation requires specific roof materials and qualifications for designers of rainwater-catchment systems. Users must also install filtration and disinfection systems. Cisterns must be able to accommodate enough storage to last through typically dry summers.

“Use of rainwater as the sole source for household water encourages conservation every day, and conservation is the way we will be able to meet the water demands of the future,” Lambert said.

Warren Kagarise: 392-6434, ext. 234, or Comment at

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2 Responses to “King County OKs rainwater as sole drinking water source”

  1. Steve on July 27th, 2011 10:27 am

    I hear that drinking roof-top rainwater can cause shingles.


  2. King County OKs rainwater as sole drinking water source « Only Ed on July 28th, 2011 2:39 am

    […] King County OKs rainwater as sole drinking water source […]

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