The drought may have all of us watching the bath water swirling down drain and thinking about wasted water. But you don't have flush away our natural resources if you install a graywater system.

Natalie Kilmer with Greywater Action in Oakland took some of the mystery out of the water reuse systems at this week's Our Garden class.

Waste not, want not

  • Much of the water that we use to do laundry and take baths and showers can be diverted to our landscape using simple or complex systems.

  • The benefits to using graywater is that it can help recharge aquifers, reduce the amount of water going to water sewage treatment centers, reduce our use of fresh water, and lower our water bills.

    Is it legal?

  • Counties may have different protocols when it comes to graywater, but a number of systems are included in the state's plumbing codes.

  • As long as you follow the guidelines for installing a graywater system, it is allowed by law.

  • There are some restrictions. Water from toilets and kitchen sinks cannot be integrated into a graywater system.

    Things to know

  • Graywater cannot be stored for more than 24 hours. After that, it is classified as black water and cannot be used on a landscape. It must be redirected to the sewer.

  • The most common and easiest to install and operate is the laundry-to-landscape system. It takes the water from your washing machine and sends it directly to your landscape, passing through a simple filter before being released.

  • Laundry-to-landscape systems do not require a permit, and most people can easily install them.

  • Another popular type of graywater system is called branch drain. It is typically installed to divert water from the bathroom sink, shower and bath.

  • The installation requires cutting into the existing plumbing and most people will need to hire a plumber to accomplish the full installation.

  • Branch drain systems require a permit.

  • If you don't want to install a system, or don't own your own home, you can still divert water from your bath or shower by catching the water in a bucket. You still need to discharge it within 24 hours, and you may find it easier to do that by using the water to flush toilets.

    What to do, what not to do

  • Don't pick a complicated, expensive system if you aren't willing to maintain it. In systems with pumps, the pumps must be cleaned regularly or they will burn out.

  • Avoid contact with the water. Although it is generally not harmful and can be safely used in most of your garden, it is waste water and unfit for consumption. Make sure children and pets are kept away from the discharge.

  • Graywater can be used to water your landscape and vegetable garden, but not on plants such as turnips and potatoes where the fruit of the plant comes into actual contact with the water. Using it to irrigate aboveground crops, fruit trees, small shrubs, annuals and perennials is fine.

  • You can create a system that directs the graywater into your irrigation system, however these systems are expensive and require more sophisticated filters to avoid clogging the pipes.

  • Pick the system that fits your site, your finances and your lifestyle. If you don't mind cleaning pumps and keeping a close watch on the system, then pick a complex one. If you don't have a lot of money or time, you may want to go with a very simple plan.

  • Be sure to follow all of the guidelines state law requires when setting up your graywater system.

  • Pay attention to the products you use. Some shampoos and soaps have sodium compounds and chemicals that can be harmful to the soil and plants.

  • If using a laundry-to-landscape system, don't discharge water from loads where you have washed dirty diapers, clothing with hazardous waste, bleach or toxic chemicals.

  • Make sure your system has a three-way valve that gives you the option of releasing water onto the landscape or sending it to the waste treatment center.

    Our Garden

    Our Garden offers free gardening classes 10 a.m. to 11 a.m. every Wednesday, through October. The garden is located at Wiget Lane and Shadelands Drive in Walnut Creek. Master Gardeners are available to answer your questions and diagnose disease and pests, and there is a wide variety of plants for sale.

    Next time in the Garden: Central Contra Costa Sanitary District's Composting for Busy People, with Master Gardener Linda Mizes.