Water Use Study Aimed at Wasteful Homeowners

The San Fernando Valley is home to many dedicated lawn waterers.

Some of them also water parked cars, the mailman and youngsters on bikes.

In many Valley neighborhoods, particularly on dry hot days, the sidewalks and streets glisten with streams of water from sprinklers badly missing their marks. It is as if, having made a semi-desert bloom, people are trying to duplicate the same miracle with the pavement.

According to the Los Angeles Department of Water and Power, lawn sprinkling by homeowners accounts for nearly one-sixth of all the water used in Los Angeles. In the San Fernando Valley, outdoor water use at single-family homes averages about 85 gallons per person per day.

Concerned about wasteful irrigation practices, the DWP is about to launch a study, focusing on the Valley, to determine how best to reduce water waste in lawn care. The $81,400 project will involve 275 homeowners and test several approaches to get them to improve their watering habits.

The DWP hopes to begin recruiting homeowners to participate in the study by the end of January, according to Doug Gillingham, an assistant planning engineer.

Water Restrictions Proposed

DWP officials also may propose an ordinance that would prohibit errant sprinkling onto sidewalks and gutters, ban the hosing of pavement to clean leaves and grass and prohibit watering in the midday heat, when much of the moisture evaporates before it can do any good, Gillingham said.

He said department officials expect such a proposal to be controversial. But he said that, besides direct water savings, the measure would raise public awareness about the value of water.

Even when a lawn is cared for properly it can consume more water than that most conspicuous of water users, the swimming pool, according to a recent report by the California Department of Water Resources. A 25-by-40-foot lawn typically needs about 27,000 gallons of water a year, but a pool occupying the same space requires 17,000 gallons a year to replace losses from evaporation and to clean the filter, according to the report.

The comparison assumes that the lawn gets the right amount of water, but many homeowners overwater by up to 40%, according to the report.

Water Savings Measured

The lawn-watering study, which is being paid for by the DWP, the state Department of Water Resources and the Metropolitan Water District, will measure the water savings achieved through information programs and moisture-sensing devices.

Gillingham said the DWP will recruit participants for the study through a mailing to several thousand homeowners who have automatic sprinkler systems. Virtually all the notices will be sent to Valley residents, he said. A few others will go to West Los Angeles, he said.

About 100 homeowners will merely have their water use monitored during the two-year study. The 175 other participants will play more active roles: 50 will be given printed information on prudent lawn-care practices, 50 others will get that information plus a guide showing exactly how much watering is needed, and a third group of 50 will get the information and the guide, plus specific advice from landscape experts.

The remaining 25 participants will get all three forms of advice and will also have moisture-sensing devices--called tensiometers--installed in their lawns to prevent overwatering.

Gillingham said the tensiometer--basically a tube with a ceramic tip on the bottom and with wires and a gauge on top--will stop the automatic sprinkler system if moisture levels in the earth make watering unnecessary.

He said water consumption by the participants will be tabulated over two years and compared to their water use in previous years.

Gillingham said tensiometers cost about $50 and are used by golf courses. Their cost-effectiveness for residential users is uncertain, however, and one purpose of the study is to determine if they can cut water bills enough to interest homeowners in buying them.

Gillingham said the proposal to penalize wasteful outdoor water use may be included in a draft of a water management plan that the DWP hopes to release in the spring. A state law passed last year requires water utilities to adopt such plans to promote more efficient use of water.

Gillingham said such an ordinance, carrying fines much like traffic tickets, would likely meet some public resistance and enforcement problems. He said that, although errant sprinkler heads normally are easy to adjust by hand, costly modifications could be needed in some cases. Officials would have to decide if “it is fair and reasonable to ask people to do that,” he said.

Water officials say more efficient water use is needed to prepare Los Angeles for possible supply reductions caused by court rulings, pollution and drought.

The DWP relies on water from the Owens Valley and Mono basins for about 77% of its supply, but pending litigation by environmental groups eventually could reduce this supply by cutting diversions from the Mono basin and ground-water pumping in Owens Valley.

About 16% of the city’s supply is ground water pumped from DWP wells, most of them in the eastern San Fernando Valley. But a dozen of these wells have been closed in recent years because of pollution by the toxic solvents trichloroethylene and perchloroethylene. It is unknown if contaminant levels have peaked or if more pollutants will seep into the wells, putting more of them out of service.

The DWP buys the rest of its water from the Metropolitan Water District, but the MWD will lose a large volume of its Colorado River supply to Arizona after 1985 because of a court ruling.

Water officials say that most people could significantly reduce their outdoor water use without any expense or hardship. They recommend such simple techniques as:

Raising the height of the lawn mower (most lawns are cut too short, exposing roots to the sun and raising water loss).

Mulching roots around trees and shrubs with bark, sawdust or stone to hold in water.

Phasing out plants that require large amounts of water.

Catching rainwater in barrels under downspouts and eaves for use on the garden or lawn.