Rainwater collection is certainly nothing new, humans have been doing it for thousands of years. However, with the advent of cheap, potable water delivered right to your doorstep, those who harvest rain have become somewhat of an anomaly. This is changing in Washington State, largely for three reasons:

• Rainwater collection can be a tool in the stormwater management toolbox,
• Rainwater collection can be an eco-friendly water supply,
• Rainwater collection projects can be a sound investment  not only monetarily but for the Puget Sound.

With all of the benefits of rainwater collection it seems hard to imagine why there would be any barriers to it gaining popularity, other than upfront costs.  In areas directly bordering the Puget Sound, rainwater catchment presents no issues of concerns as the rain, if not captured and used, would otherwise have quickly become stormwater runoff into the Sound – capturing and using that runoff is a good thing.

In other parts of the state it can be a different story - water has often been fully or even over-appropriated. Even in normal precipitation years, junior water right holders sometimes get curtailed.  In these areas, rainwater collection in conjunction with consumptive use could potentially reduce the water supply for other water right holders, including streams that have an instream flow right.  In Washington State this sort of injury to senior water right holders is called “impairment.” It is Ecology’s duty to not issue new water rights that would cause impairment to senior water right holders.  Ecology is currently in the beginning phase of rulemaking that will help to clarify current ambiguous existing water law relating to rainwater collection by:

• Delineating the historical water code and permit exemption storage thresholds for rainwater collection,
• Delineating specific rules for attaining permits and permit exemptions in closed basins,
• Specifically authorizing priority processing for rainwater collection systems due to associated stormwater management benefits,
• Creating new individual and regional permit applications for rainwater collection systems

Contact

Brian Walsh
Department of Ecology WR-HQ
Phone: 360 407-6647
E-mail: bwal461@ecy.wa.gov