Sustainable Contra Costa Action Guide

Greywater Systems

Did you know . . . ?

Greywater is water from your showers, bathroom sinks, and laundry machines. It has not come into contact with feces or used diapers. Utilizing grey water saves money, conserves fresh water resources, aids plant growth, reclaims otherwise wasted nutrients, and decreases dependence on chemicals. Greywater may contain traces of dirt, food, grease, hair, and certain household cleaning products, and while it may look dirty, it is a safe and even beneficial source of irrigation in a yard. There are many simple, economical ways to reuse greywater in the landscape, four of which are described below. For more information on installing each type of the following systems, you may visit http://greywateraction.org/content/about-greywater-reuse.

How-to

The easiest way to use greywater is to pipe it directly outside and use it to water ornamental plants or fruit trees. Greywater can be used directly on vegetables as long as it doesn't touch edible parts of the plants. Be sure to put nothing toxic down the drain—that is, no bleach, dye, bath salts, cleanser, shampoo with unpronounceable ingredients, or products containing boron, which is toxic to plants. You must use all-natural, biodegradable, sodium-free soaps whose ingredients do not harm plants.

Guidelines for reusing greywater properly:
1. Don’t store greywater for more than 24 hours to prevent the nutrients from breaking down and creating foul odors.
2. Minimize contact with greywater, because it could potentially contain a pathogen. Your system should be designed for the water to soak into the ground and not be available for people or animals to drink.
3. Infiltrate greywater into the ground, don’t allow it to pool up or run off. Pooling greywater can provide mosquito breeding grounds, as well as a place for human contact with greywater.
4. Keep your system as simple as possible by avoiding pumps and filters that require upkeep. Simple systems last longer, require less maintenance and energy, and cost less money.
5. Install a 3-way valve for easy switching between the greywater system and the sewer/septic for when toxic substances must pass through the drain.

There are some simple and effective greywater systems you may want to learn more about and install.

Laundry to Landscape

This system is best if you're looking for system that gives you flexibility in what plants you're able irrigate and takes very little maintenance. The washing machine’s hose is attached to a valve that allows for easy switching between the greywater system and the sewer. The greywater goes to a 1" irrigation line with outlets that send water to specific plants. This system is low cost, easy to install, and gives huge flexibility for irrigation.

Showers- “Branched Drain” System

Showers are a great source of greywater, as they usually produce a lot of relatively clean water. To have a simple, effective shower system you’ll want a gravity-based system that does not use a pump. If your yard is located uphill from the house, then you'll need to have a pumped system. Greywater in this system utilizes gravity to flow through standard 1.5" drainage pipe sloping downward at 2% slope, or 0.25” drop for every foot traveled horizontally, and the water is divided up into smaller and smaller quantities using a plumbing fitting that splits the flow. The final outlet of each branch flows into a mulched basin, usually to irrigate the root zone of trees or other large perennials. Branched drain systems are time consuming to install, but once finished require very little maintenance and work well for the long term.

You don’t have to set up your greywater systems alone! Contact a trained Greywater Action Associate for help on installation of any of these systems. http://greywateraction.org/installers

Resources

Greywater Action http://greywateraction.org/content/about-greywater-reuse

Learn more about installation and discover which system is best for your needs.

Central Contra Costa Water District http://www.ccwater.com/conserve/alternatives.asp

Read the county’s recent greywater bill.

-by Gwen von Klan in collaboration with Greywater Action http://greywateraction.org/