Greywater: The green way to water every day

Two weeks ago, the City of Oxnard joined other local cities in passing restrictions limiting watering of landscape. Similar to the restrictions passed last month in Simi Valley, residents of the City of Oxnard are now allowed to use outside irrigation just one day per week, on Sundays only if your address ends in an odd number, and on Saturdays only if your address ends in an even number.

Hand watering of trees and other perennials on other days with a container, a drip system, or a hose fitted with a shut-off nozzle, is still allowed, but these restrictions will require changes from many residents, and even local areas not receiving water from the Metropolitan Water District are considering similar limitations.

Regardless of these restrictions, there is a green way you can legally water every day.  

Greywater capture systems enable you to reuse some of the water you use every day inside your home. Greywater is the reusable water from sources such as sinks, showers, and laundry machines. It contrasts with blackwater, from sources such as toilets and dishwashers, which cannot be reused on site without treatment.

Greywater systems save water, preserve landscape, and save money. There are two basic types of systems. “Laundry to landscape” systems are relatively simple, and some local jurisdictions do not even require a permit, provided no pipes are cut and other rules are followed. “Showers to flowers” systems are more complex. Either system must follow guidelines to avoid hazards.

Simply running a garden hose from a clothes washer out the window to a lawn, garden, or tank with a pump, is not the way to begin using greywater. These primitive systems violate building and safety codes, and they often do not accomplish their intended purpose anyway. Flows from a graywater system are generally not sufficient to sustain a lawn, and systems using simple hoses or a non-perforated pipe to distribute water frequently dump excessive water into one, small spot. Avoiding mosquito-attracting ponding of water is one of the cardinal rules of greywater reuse, so these practices do not comply with regulations.

Application of graywater to a vegetable garden is also not advised due to the presence of bacteria in the water. “Graywater can contaminate low-to-the-ground vegetables such as carrots and strawberries. It is safe, however, to use graywater for irrigating citrus and avocado trees, if done correctly,” according to Dan Drugan, Manager of Resources at Calleguas Municipal Water District.

Rules vary by city, so check with your building and safety department, but all 11 local jurisdictions adopted general guidelines for laundry systems in 2010 and for “simple” systems in 2015. Although these will soon be updated with minor changes, according to Ventura County Building Official Ruben Barrera, the versions currently displayed on the Ventura County Resource Management Agency website, at, currently provide a useful overview.

Two of the most basic guidelines relate to plumbing. Graywater must be channeled to a landscape through pipes, rather than being sprayed. Also, a diverter valve must be installed so water can be sent to the sewer for treatment if it contains grease, blood, urine or feces.

If you install a greywater system, remember to use biodegradable soaps and no harsh chemicals. Also, perform regular cleaning and maintenance on your greywater system to keep in working properly.

 Finally, keep in mind the most typical barrier to use of greywater systems in Ventura County. Water delivered to many local homes is hard enough to inhibit shower lathering, leave spots on dishes, and eventually to leave build-up restricting the flow of water through small holes in shower heads, dishwashers, and faucet filters. Consequently, people use water softeners, presenting a barrier to water reuse. “Homeowners who use water softening systems, which remove minerals by using sodium or potassium, may slightly increase the salt content in water used at home. Reusing this water through a greywater system leaves additional salt in the landscape, (building up over time and) damaging plants,” according to Drugan.

Installation of a legally compliant greywater system can cost hundreds of dollars, but dividends include water savings and enhanced landscaping, which can add several thousand dollars to the value of a home.

Greywater systems also reduce outflow to a sewer or septic system, but do not expect monetary savings from this benefit. Charges for homeowner’s outflow to sewer are still measured by the amount of water consumed, and the required size of a new septic system is not reduced when built in conjunction with a greywater system. Sean Debley, Manager at the Ventura County Environmental Health Division, explained why greywater does not reduce septic system requirements. “Septic systems have to be sized to account for rainy periods or other times people use their diverter to channel water away from landscape.”

On the web: David Goldstein, Environmental Resource Analyst with the Ventura County Public Works Agency, may be reached at (805) 658-4312 or