Harvesting rooftop rainwater

Recent rule changes clear way for rain recapturing systems

BY TIMOTHY BUCKLEY Greenstone Architecture

Green-building proponents and developers of building projects recently gained a long-awaited tool to help builders meet the region's more stringent stormwater ordinance standards in the emerging area of rainwater harvesting.

In the past year, the VBJ published several articles regarding updated stormwater requirements and its potential economic impact in regards to the technical feasibility and projected cost of the new standards.

Capturing and storing rainwater for onsite use for irrigation or even flushing toilets is considered environmentally responsible since it reduces storm event impacts by reducing downstream erosion, sedimentation and storm surge peaks. It also slows the release of water back into the system and reduces demand for municipally-treated potable water drawn from our local aquifers.

Local examples of companies using rainwater collection systems include Columbia Credit Union's new Washougal and Grand Central branches, which have been certified LEED Gold by the U.S. Green Building Council. Clark County also has several residential projects using filtered and treated rainwater, including the Felida Living House and Living Farm House.

On Oct. 13, the state Department of Ecology issued a new policy clarifying its rules on water harvesting. Beyond residential-scale rain barrels - which were previously exempt - building owners no longer have to acquire a permit to harvest, store or reuse rainwater from rooftops.

For years, the region's green building community has been working with the DOE and the State Legislature to get the rules changed. Unlike our neighbors in Oregon, developers wishing to harvest rainwater in Washington were required to wade into a state water rights permit backlog - considered by many to be a futile effort.

Until now, legislative efforts over the past eight years to modernize the state's Surface Water Code have been unsuccessful. The new DOE policy now determines that "existing laws may be reasonably interpreted that the on-site storage and/or beneficial use of rooftops." However, the agency retains the authority to develop new restrictions if overharvesting is causing negative impacts.

While caution make sense in sensitive watersheds like the Yakima Basin, our mild, wet climate experiences an overabundance of rain that puts a priority on stormwater issues.

"Hopefully, Washington's practical policy will show other western states that are struggling with this issue - notably Colorado - that there is a rational path forward on this issue," said Kurt Unger, a DOE hydrologist and attorney.

As demand for greener buildings grows, and water conservation and aquifer capacity becomes more of an issue, we expect to see more and more projects in the West using rainwater harvesting as one of many strategies to make them more environmentally responsible.

Timothy Buckley is principal of Vancouver-based Greenstone Architecture PLLC. He can be reached at tbuckley@greenstonearchitecture.com.

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