Category Archives: Potable

Potable, Rainwater Catchment

More Residential Potable Use Permitted in Washington State

Rainwater Collection for residential potable use is increasingly being accepted by Washington State counties.

Close-up of a worn, metallic fountain pen nib on a black surface.

What started in San Juan county years ago with a county exemption of the 1,800’s water rights laws, rainwater collection for residential potable use is gaining momentum up and down the I-5 corridor. Whatcom, Skagit, Snohomish, and King counties all have adopted residential potable rainwater collection systems as an alternative water source for residential building permits. Each county has its own policies & procedures and guidelines for designs and installation available to the public.

The national organizations, American Rainwater Catchment Systems Association (ARCSA) , American Society of Plumbing Engineers, (ASPE) , and the American National Standards Institute (ANSI) developed the standard ARCSA/ASPE/ANSI 63 as a guideline for professionals and local governments in implementing rainwater collection and was updated in 2020. As more counties are expressing interest in rainwater collection as a viable source for domestic potable use, RainBank Rainwater Systems continues to provide updated information for these organizations to formulate decisions, and help guide them in their policies and procedures with regard to implementing rainwater collection.

With 20 years of experience, RainBank Rainwater Systems has been serving all Washington State counties with quality engineered systems and professional installations, using only the best components.

After all, it is your water supply and we take it seriously.

Potable, Residential Rainwater Collection

Potable Residential Rainwater Use is On the Rise

PoClose-up of a worn, metallic fountain pen nib on a black surface.table residential use of collected rainwater is on the rise since the statewide water rights laws were challenged in 2006 by the Washington Department of Ecology, allowing the entire state of Washington to collect and use rainwater for non-potable (non-drinking) use. San Juan County had been awarded an exemption to the 1800’s water rights laws and was already issuing residential building permits with rainwater collection as the only source of water. RainBank’s president, Ken Blair, was personally awarded a building permit in 2002 for his “water availability” being the only source of water for his household. It was not the first, but was certainly at the forefront of rainwater collection’s progression and, throughout the years, RainBank, has continued with that effort.

For close to 20 years, RainBank has shared its deep rainwater collection knowledge, working with many counties as they move toward increased adoption of potable residential rainwater collection systems for single family residences, and remains committed to providing quality engineered designs, professionally installed.

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Potable, Rainwater Catchment

Storey’s Water Tower


Close-up of a worn, metallic fountain pen nib on a black surface.A designed rainwater collection system for the ages, Storey’s water tower was designed and built as a sole source rainwater collection system for a household in the San Juan Islands of Washington State. The Storeys constructed a home on an isthmus with panoramic water views facing either side of the house. While spectacular, there was little chance of drilling a potable well, since water was only 150 feet from either side of the house. The total square foot of the house and shop would yield approximately 900 gallons per inch of rainfall.

The water is screened as it enters the roof gutter system, then finer screening and sedimentation occurs before gravity feeding into the sump tank. A float switch will activate a sump pump to convey water to this magnificent water tower, with a office space on top, to enjoy those views.

The system is pressurized with a with a centrifugal pump and pressure tank which feeds a 5-micron sediment filter followed by carbon filtration. The Story’s were pleased with their new system even though “It lacks mineral value, but that’s alright, as long as it keeps one mineral out – salt water.”, saidMrs. Storey. That was 1977!

Close-up of a worn, metallic fountain pen nib on a black surface.Coincidentally, I visited this house in the mid-eighties, before I had knowledge of rainwater collection. I was fascinated with the concept and impressed with the design and craftsmanship. The thought of a self-sustaining water system, when no other source was available, made perfect sense. The simple mechanics of prescreening, pre-filtering, andpressurized conveyance is the basis of best practices still used today.

I had an opportunity last month to conduct an inspection of this system for the new owners and was thrilled to see. with a few improvements and UV sterilization, this system is still producing a sustainable source of potable water, and can be expected to continue for another forty years.