Rainwater harvesting is permitted in parts of King County (Photo: grifray on Flickr)


Last week, the King County Board of Health approved a measure that will permit many in the area to use rainwater as the sole water source in their home. Yes, that means that rainwater can serve to flush your toilet and wash down your supper. So, how far does this measure reach?



The County’s new measure spawned from a number of homeowner pleas. Homeowners in more rural areas of the County had hoped to use rainwater to offset poor accessibility of public water sources. In many areas, its nearly impossible to extend public water lines or to rely on a well – so rainwater harvesting has become an intriguing concept.


But, the County measure is not an open invitation to all property owners – it comes with conditions. First of all, the measure appears limited to single family homes. Many business owners and commercial building designers have clamored for permission to use more rainwater. Rainwater is cheap, accessible and about as sustainable as you can get, so its easy to see the attraction.


Secondly, you must meet two conditions: (1) the home must have its own septic system and (2) you must show that connecting to the public water system or drilling a well creates an undue hardship. Thus, this permission will only apply to those living in rural areas or those crafty enough to meet these exceptions through other means.


My feeling? This new measure is just a drop in the bucket. I presume that the Board of Health will consider opening this up as water filtration systems improve and scientific testing shows that filtered rainwater is actually more healthy than the public water source. As some people begin using rainwater, others will ask “why not me?”


For green builders, this is a new option for retrofits and new construction. Contractors should check with your local health codes to ensure that rainwater harvesting is permissible.