Tag Archives: Seattle

How-to, Rainwater Catchment

Is Sole Source Use of Rainwater Collection Legal in King County?

lake-176942_640There has been a great deal of inquiry about sole source use of rainwater collection in King County, causing confusion for the public – as well as for King County public officials. RainBank is currently consulting on four different projects, assisting clients with navigating the system.

A change in Department of Public Health Policy, which is the authority on single source rainwater collection, has been transferred back to the Onsite Sewage System Authority (OSS) of King County Public Health.

There is a section of Title 13 that refers to rainwater collection for single source usage. This authority has jurisdiction over sole source use; any other permitting approval for supplementary source is to be approved by King County Public Health Department’s senior plumbing inspectors. There are plumbing codes that must be met with regard to installation and permitting from KCH plumbing division for any RWC system that is potable or non potable, that is connected to household plumbing.

Below is the section of Title 13 dated November 20, 2013, which refers to sole source usage

D. A rainwater catchment system that serves as the only source of drinking water for a single family residence and that complies with each of the following conditions:

1. The health officer finds that requiring connection of the plumbing system to an approved public water source or to an approved private well would cause undue hardship.

2. Application for a rainwater catchment system source approval shall be submitted for review on forms provided by the health officer. The applicant shall pay to the health officer the rainwater catchment system review fee as specified in the fee schedule, payable after completion of the application review.

3. Application for a rainwater catchment system source approval shall be prepared by any one or more of the following:

a. A professional engineer authorized under a current, valid license to practice in Washington state;

b. An environmental health professional holding a current, valid registration from either the Washington State Environmental Health Association or the National Environmental Health Association;

c. A King County licensed water system designer holding a current, valid license to design water systems in King County; and


d. A rainwater system designer holding a current, valid accreditation from the American Rainwater Catchment System Association.


4. Rainwater catchment system source design shall conform to Part III of Chapter 16 of the Uniform Plumbing Code, 2009 edition, as amended, and shall include, at a minimum, the following information:

a. Estimated daily and weekly and annual demand;


b. Available catchment area and estimated annual rainwater capture;


c. Roofing materials used;

d. Storage capacity of and materials used in the construction of the rainwater catchment system; e. treatment specifications including filtrations and disinfection system specifications; and


f. Operation and maintenance requirements.

5. Composite or shake shingles or other materials determined by the health officer to present a risk of contamination may not be approved or used as roofing materials for a rainwater catchment system source.


6. Before using a rainwater catchment system source, the property owner shall file in the county recorder’s office a notice on title advising that the property is served by a rainwater catchment system and including the following information:

a. The estimated daily, weekly and annual water supply furnished by the rainwater catchment system;

b. That the water supply from the rainwater catchment system may be limited due to variations in rainfall or usage; and

c. That regular maintenance of the treatment system and components is required in order to minimize the risk of consuming contaminated water.

As rainwater collection becomes less of a niche and more mainstream for residential and commercial applications, and with 15 years of design and installation experience, RainBank is the go-to source and your advocate for rainwater collection systems in the Pacific Northwest. Using the form below, contact us today to learn how we can help you with proper system design, installation and consultation through the sometimes confusing permitting requirements for potable, non-potable, sole source and supplementary systems in and around Seattle, Washington state and beyond.

Environment, Sustainability

Can You Collect Rainwater in Seattle’s Tight Living Space?

Space_Needle_Mount_Ranier_Seattle_Washington_USAYou live in Seattle, where space is at a premium. You may not have a large lawn for tank placement, but you still want to live sustainably. You’ve already reduced your household and business energy usage and you recycle and reuse products to extend their life. So, how can you capture a vital resource by collecting rainwater in Seattle’s tight living space?

  • Just like rural homeowners, urban households can benefit from rainwater collection. Unlike rural homes, most city homes have less space available for storage. Slim line water tanks and underground storage options allow those who live in an urban environment to collect, store, and use rainwater for a number of purposes.
  • chartYou do not need a lot of storage capacity for supplemental use of rainwater. For every inch of rainfall, a thousand square feet of surface will yield 623 gallons of water. A 2,000 square foot roof in Seattle will yield over 44,000 gallons of water annually. Even with only 3,000 gallons of storage, winter use can be as much as 100% or can be stored for summer irrigation demands. See chart below  – an average 2,000 square foot roof yields over 44, 000 gallons with only 3,000 gallons of storage capacity based on 120 gallons of daily demand.  (click the image for larger view)
  • Rainwater is a clean source of water that needs very little treatment for irrigation, toilet flushing, or laundry facilities. Further treatment with UV disinfection allows for whole house demands including drinking water. With more demands on our water districts due to drought conditions, every drop helps. Why not benefit from this natural resource, rather than send it down the curbside drain?

It is possible to further your conviction to live a sustainable life with rainwater collection. The investment can pay off not just for you, your family, and your business, but for all of us who seek to make the best use of rainwater, a vital resource.

This article was originally published under the title How Can Urban Homes Benefit From Rainwater Collection?

Environment, Infrastructure

Water Supply Predictions from Seattle Public Utilities

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Seattle Downtown After RainThe water supply prediction scenarios from Seattle Public Utilities are in – and the outlook isn’t good for Seattle and Washingtonians.

According to an article on Grist.org titled, This Drought is so Bad That Even Seattle is Running Out of Water, “Almost all the future scenarios modeled by SPU showed big drops in what’s known in water-utility lingo as “firm yield”: the amount of water that can be reliably delivered. Even assuming a drastic cutback in the amount of greenhouse gasses being emitted today, Seattle is looking at reduced firm yield of an average of about 30 percent through 2050, according to three of these future climate simulations. …”

One option for increasing water supply includes drawing water from Lake Youngs, but that might pull mud into the water supply, requiring expensive water treatment. Water from Puget Sound is an option but that would involve costly desalination.

So, what’s one of the country’s the fastest-growing cities to do? Although Seattleites have been proactive about conserving water usage over the last 50 years with efforts like low-flow toilets, there’s only so much cutting back you can do when supply is tight.

An article on InvestigateWest titled, Climate Change is Darkening Seattle’s Water Forecast, shares that water supply predictions are dire, even though models may be incomplete and involve guesswork and assumptions based on “what-if” scenarios.

“Quietly unveiled to regional water managers over the summer, the admittedly incomplete — and yet extremely sobering — calculations show the amount of water Seattleites can count on could be reduced by as much as half over the next 35 years and nearly three-quarters by the end of the century.”

The article goes on to share: “The climate models are not perfect,” acknowledges SPU climate researcher Paul Fleming. But these simulations are clearly showing that “climate change will increase the magnitude and the likelihood of those events occurring,” Fleming said.”

Seattle, it’s time to go beyond conservation efforts like taking shorter showers and running your dishwasher less often. Do you know that with rainwater collection, you can have your own supply of water for washing laundry and flushing toilets? In some areas, you can even collect your own drinking water.

RainBank customers are already benefiting by collecting rain. Read more about RainBank systems in Bellevue, Vashon Island and the Puget Sound area and how folks are proactively dealing with More Cuts To Seattle Water Usage.