Believe It Or Not, We Are Now Allowed To Use The Water That Falls From The Sky

…also known as rainwater harvesting. Humans have been doing it for tens of thousands of years, of course. But until this month, it has been illegal to harvest rainwater for indoor use in Seattle. Given that rainwater harvesting has the potential to reduce both potable water demand and sewer system load, how did this odd circumstance arise in the first place?

The Washington State Department of Ecology controls water rights for the entire State, and it’s serious business. Water rights regulation was first established to keep tabs on water used for farming irrigation, and set limits on the amounts that can be drawn from natural sources. As I understand it, rainwater capture has been off limits because it may divert runoff from natural water bodies.

Kudos to Seattle and King County for hammering away at the WA DOE to get these antiquated regulations updated. Rainwater harvesting for non-potable use is now permitted in Seattle, though only on sites that drain to the combined sewer system. With this limitation, there will be no effect on stormwater that drains directly to natural water bodies such as Lake Washington.

Though I shouldn’t speculate because I really don’t know what the hell I’m talking about, speculate I shall: I’m guessing that in Seattle there would have to be scads of buildings harvesting rainwater before the local water bodies would be affected in any significant way. Scads, as in, it would probably take decades for us to ever reach that point, if we ever would. If my guess is correct (and don’t hesitate to shoot me down if you can), Seattle needs to keep pushing for rainwater harvesting rights that cover the entire City, cause even here in the soggy Pacific Northwest, water can’t be taken for granted.

6 Responses to “Believe It Or Not, We Are Now Allowed To Use The Water That Falls From The Sky”

  1. Adam P

    I think that most of seattle has a combine sewer and overflow (CSO) system. This means that even runoff from the road goes to the sewage treatment facility. This type of system is a remnant of when we had horses pooping all over the road.

    This weekend I went to the Greenfestival and heard a presentation on living buildings. Do you know if there are any projects in the area trying to achieve the living building level? It would seam that rain harvesting is almost essential for an building try achieve the living building level.

  2. dave

    I’m confused. Aren’t rain barrels a form of “rain harveting”? The city and county have been promoting the use of those for years.

  3. Matt the Engineer

    Technically even this water belongs to the state, although the state allows residential sized rain barrels without a permit. (pdf here) Which is good because of funding issues a water rights permit could take years to approve. I’ve worked on several green building projects that wouldn’t consider rain harvesting because of this.

  4. Matt the Engineer

    Oh and before that 2007 pdf memo, it really wasn’t even clear that residential rain barrels were legal without a permit.

  5. Adam P

    It is one thing to use water from a roof to water plants, it is another to use it in a building.

  6. michael

    Actually, there are several projects that use harvested rain water for indoor use (toilet flushing mainly). Just a couple examples include Seattle’s City Hall, and the Taylor 28 project currently under construction. Incidentally, Taylor 28 is a major reason why Seattle is now exempt from these antiquated regs that are grounded in eastern WA agriculture (saw a presentation on this last week).

    The state has essentially not enforced water rights legislation that would apply to rainwater harvesting this side of the mountains, which is why large commercial projects have been built with rain harvesting systems, and the City has been selling rain barrels for several years, even before this exemption.

    Of course, as Seattle continues to separate its sewers, this exemption will look more like an interim step…it will have to be revisited sometime in the future.

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