Go Green with Graywater!

August 6, 2015

Woodside should be a water conservation leader rather than a water hog. We should all be embarrassed by headlines like this ”Wealthy Woodside Is Among State’s Top Water Wasters”. See our prior story here.

The Town should facilitate the use of gray water systems and other water conservation features. Encouraging systems that put water back into the ground on site or into cisterns for reuse on properties instead of into storm water systems that flush usable water out into the bay. Our Town should offer incentives, such as fast tracked permitting, low or no fees, “how to” information handouts and/or how to seminars. Perhaps the Town could sponsor a Water conservation “fair” where companies can come and show people what they can offer. Water is precious – we need to conserve and Woodside could and should be a leader in this effort.

One way to cut back on water use is to use graywater — recycled water from showers, sinks, and washing machines. State law allows homeowners to install their own recycled water capture systems without a permit unless the city or county adopts stricter regulation. Effective 2010, the Department of Housing and Community Development issued new somewhat liberalized Nonpotable Water Reuse Systems regulations. See Title 24, Part 5, Chapter 16A. The regulations provide guidance for avoiding potentially unhealthful conditions.

The typical household produces an average of 60 to 90 gallons of graywater each day. There are various systems that can irrigate with untreated water from bathroom sinks, washing machines and showers, but only if the water runs underground beneath soil or mulch. The untreated water must not come into direct contact with people or food. For example, untreated gray water could be used on tomato plants but not to root vegetables. Graywater does not include wastewater from kitchen sinks or dishwashers.

Basic Guidelines:

1. A 2” cover which can be mulch, rock, or soil, or a solid shield is required. The code does not define how the water is to get from the washer machine to the irrigation area, nor how it enters the soil

Irrigation Field. An intended destination for graywater in the receiving landscape including but not limited to a drip irrigation system, mulch basin, or other approved method of dispersal for irrigation purposes.

Mulch Basin. A type of irrigation or disposal field filled with mulch or other approved permeable material of sufficient depth, length and width to prevent ponding or runoff. A mulch basin may include a basin around a tree, a trough along a row of plants or other shapes necessary for irrigation or disposal.

2. Graywater shall not be used in spray irrigation, allowed to pond or runoff and shall not be discharged directly into or reach any storm sewer system or any surface body of water.

3. Don’t store graywater (more than 24 hours). If you store greywater the nutrients in it will start to break down, creating bad odors.

4. Minimize contact with graywater. Your system should be designed for the water to soak into the ground and not be available for people to touch or animals to drink.

5. Infiltrate graywater into the ground, don’t allow it to pool up or run off. Pooling graywater can provide mosquito breeding grounds as well as a place for human contact.

6. Keep your system as simple as possible, avoid pumps, avoid filters that need upkeep. Simple systems last longer, require less maintenance, require less energy and cost less money.

There are many simple do-it-yourself systems described on the web. For more information see here, here, here and here.

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