Washington State Drafts Rainwater Collection Rule

Members of the public will have an opportunity to learn about rainwater collection and to discuss a new statewide rule on Wednesday, July 16, 2008, in Aberdeen, where the fourth in a series of workshops being held around the state is scheduled.

The open house will begin at 6 pm at Aberdeen High School, The Commons, 410 North G. Street in Aberdeen.

"A statewide rule would remove ambiguity about rainwater collection from existing water law," said Brian Walsh, the Department of Ecology's policy and planning manager for water resources. "We want to ensure that collection and storage of rainwater happens in a way that is consistent with protecting stream flows and water rights."

The Department of Ecology does not require homeowners to obtain water right permits to collect and store small amounts of rainwater. The new rule would, for the first time, define how much rainwater can be collected and used before a permit is required.

The Seattle Space Needle in the rain (Photo by Samir Diwan)

Under state law, rainwater is considered a water resource of the state. To use the waters of the state, an individual or group is required to get permission from the Department of Ecology in the form of a water right permit.

The state agency wants public comment on what the threshold should be for requiring a water right permit for those systems that could affect the water supply of senior water right holders or stream flows in some river basins.

The impact of rainwater collection systems depends on their size, location, the number of systems in a particular area, and the amount of water already appropriated in a basin.

Residential rainwater collection systems range from a 50 gallon rain barrel to cisterns of 30,000 gallons or more. Commercial systems can be larger.

In water-short areas like the San Juan Islands, rainwater may be the sole source of water for some homeowners.

The Department of Ecology is especially interested in encouraging rainwater collection in urban areas like Puget Sound where it can be used to reduce stormwater runoff and supplement municipal water supplies.

The new rule will not affect the regional rainwater permit recently obtained by the City of Seattle, or future island-wide permits in San Juan County.

The Seattle Public Utilities, SPU, water permit allows capture and use rainwater of collected from rooftops that would otherwise enter Seattle's sewer system, be conveyed to a treatment plant and discharged via a deep marine outfall.

The rainwater that will be captured under this permit would not otherwise end up in Lake Washington or other freshwater bodies, except during combined sewer overflow events.

Rainwater harvesting systems established under this permit will not be connected to the public water supply system operated and maintained by the Seattle Public Utilities.

But SPU says the implementation of this permit will benefit the public water supply system by reducing the demand for drinkable water that is currently used for other purposes such as irrigation for gardens, watering lawns, and toilet flushing.

It may also benefit Seattle's sewage collection system by lowering storm flows into the sewer system.

Copyright Environment News Service (ENS) 2008. All rights reserved.