Green Design: We want to reduce our water use and our runoff, please!

One of the arguments for saving water that is a struggle for owners to accept is the fact that since water is so inexpensive, the return on investment for building water saving green design systems does not pencil out. The way California and the west will reduce its water usage has to be planned for strategically, it cannot occur through economic forces. Its strange, but water here is cheap and building a cistern in your back yard is not! With the population growing and the lack of feasible future technology such as de-salinization, there will be a water shortage. We must reduce our consumption of this precious resource. In another post we mention that water consumes roughly 33% of California’s overall energy use, thus not only does saving water save water, but it saves energy also. There is an attitude shift that has to happen. Read our other post here.

In the same way that we have systems in our houses for electricity or plumbing, areas for cooking, areas for sleeping, etc., we need to expand and add a hierarchical system of how water is sourced and used. For example, we currently have water infrastructure that enables fresh clean water to come directly into our houses. We just take this for granted and this is our sole water supply. What if the standard for buildings was to have systems of rainwater catchment, greywater re-use, and on-site storage. There are technologies for all of these in various price ranges and scales, just as there are many different styles and functions of shower heads. The best solution is to have a net zero water home. Even so, there are varying degrees of how and what to build for a water conscious system in your home.

Storage

Collecting rainwater from the roof and patio is one thing, but storing it is another. We typically imagine the extensive excavation and installation of great big cisterns. A company called Raintech has a modular system that is stackable and can be used in any site condition and depth. The modules that hold water are structural, so it works to place them under the lawn or patio. Because they are modular there is no limit to how much or little water is stored and the units adapt to any shape, space or site restriction. Read more here.

Greywater to Landscape

Greywater is the water that comes from showers, bathroom sinks and the washing machine. A couple of methods for reusing greywater would be to collect it, filter it and use it to flush the toilets. Another easy use is to put it out in the landscape as irrigation. The more complicated system would be to do both whereby the more fixtures that get collected the more complicated it is. Again, its a hierarchy, and depending on budget and needs different variations could be attained. One extremely simple method is to direct the water from the washing machine to the landscape. All that is needed is a pipe, the right plants, and detergent that plants won’t mind. Detergents have phosphates in them, but actually, phosphates are also fertilizers. Additionally, the washing machine sending water to the landscape would work well using the Epic Green Solutions Company’s sub-surface irrigation technology. It is a series of submerged chambers that both stores the water and irrigates in conjunction with a sand planting bed. Grass and plants typically grow well in sand when it doesn’t drain too quickly and the Epic system is designed for this. Read more here.

Runoff

There needs to be a shift in mindset about run off water as well. We used to design sites that shed the water. Studies have demonstrated that run off water is not only wasted water but it is contaminated and our storm and sewer systems have to respond to the influx. What if all sites were required to retain all of their run off? It is possible to have different combinations of systems that retain water, filter it and keep it. In undeveloped areas, water is absorbed by the soil and percolates into the aquifers. Rooftops and pavement have diverted  rainwater into channels and drains that immediately shove it off site. Los Angeles just passed an ordinance that requires developments to mitigate their rainwater from now on. Also known as L.I.D., Low Impact Development, studies have shown that this is not only the most cost effective way to deal with storm water, but it is also recharges the groundwater and promotes the use of ecological irrigation systems. You can read more about this here.

Categories: Green Design, Remodel

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Hart Wright Architects
340 Potrero Ave
San Francisco, CA 94103
tel: (415) 503-7071