water, water everywhere…
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written by Shannon Bloemker (home owner, client, co-designer of reLEED house) Living in California gives you a heightened appreciation for water resources. It only rains for about 4 months of the year, and some years it hardly rains at all. So when it came to planning for our remodel, I knew that water sources and uses [...]
written by Shannon Bloemker (home owner, client, co-designer of reLEED house)
Living in California gives you a heightened appreciation for water resources. It only rains for about 4 months of the year, and some years it hardly rains at all. So when it came to planning for our remodel, I knew that water sources and uses were going to be a major focus.
There is an element of the LEED criteria which asks that the water falling onto the site be managed responsibly. To meet this we minimized the use of hardscape and where it was unavoidable (driveway, patios, etc.), we used grasscrete (concrete with grass woven in so that it’s driveable). We also diverted rainwater from the roof to a storage tank to be used for flushing all the toilets in the house and also as a water supply for the washing machine. It’s always felt funny to me using highly (expensive) treated drinking water to flush toilets, so this was a great solution. That we might have enough rainwater left for the laundry was a bonus – somewhat depending on annual rainfall – but still a simple plumbing element that gave us a great option.
So having to consider what to do with stormwater from the site enabled us to harvest rainwater and reduce the supply of municipal water our house would use. Building the storage tank and running the additional plumbing lines was actually a bit pricey (~$15,000), and if I had to justify it based on the cost-savings of water alone, I probably wouldn’t have done it. But relative to the overall scope of the project, it just felt like the right thing to do. LEED also gives us 4 points for harvesting rainwater, so it was worth it!
After feeling good about reducing our usage of municipal water on the supply-side, we looked at what we could do about the amount of water we’re generating as a household – gray water. Intuitively, anyone who’s stood by the shower for 5-10 minutes waiting for the water to warm up, watching that fresh, clean drinking water wash down the drain, can understand the value of trying to use that water for something better than increasing the volume at the sewage treatment plant.
Our solution was to drain all of the bathtubs, showers, and sinks (not the kitchen sink) to a collection point at a low spot on the property. There, a constructed wetland ecosystem allows natural biological processes in the soil to be an integrated filtration system for the graywater. The water is then pumped to subsurface drip irrigation lines throughout the gardens. There’s also a cool feature in California’s new graywater law that allows homeowners to send their washing-machine rinse water straight out into an adjacent garden (subsurface, of course) without even needing a permit. Coupled with the drought-tolerant native plants we’ve incorporated around the property, we should be able to forego city water for irrigation altogether.
I’m not a math person, so I don’t know exactly how much water we will be saving by incorporating the rainwater and graywater systems, but it’s enough to justify every would-be home-renovator giving it serious consideration. We haven’t exactly closed the loop, but we’ve sure put in a good-sized curve!