For the past decade, the Los Angeles Department of Water and Power has been preparing to tap a significant new supply of water to help meet demand in its growing service area. Yet, after investing $55 million in a pipeline and related facilities, the DWP put the project on hold in late April, just days before it was to begin operation. The reason was a loud, albeit belated, public outcry about the source of that new water: the Donald C. Tillman Water Reclamation Plant, which treats municipal sewage in the San Fernando Valley. The disruption of DWP's plans, even if the halt turns out to be temporary, illustrates the magnitude of the continuing public-relations challenge facing water managers as they try to tap a promising supply to meet the needs of California's booming population — namely, treated wastewater. As water gets more expensive and demand grows, wastewater recycling is expected to increase substantially. The State Department of Water Resources projects wastewater recycling will increase by about 60% to 577,000 acre-feet by 2020, and has identified the capacity for 1.4 million acre-feet a year if all potential projects identified in its 1995 survey of water providers were implemented. The DWP planned to pump treated effluent 10 miles to a spreading grounds in Sun Valley, where the liquid would percolate into the aquifer. That water, having undergone natural filtration during the long percolation process, would mix with natural groundwater and eventually would be pumped back out from wells more than a mile away, whereupon it would be chlorinated, mixed with water from other sources and piped to consumers. It would take about five years for the wastewater to complete its journey back into the municipal water system. The project would provide about 35,000 acre-feet a year — enough to supply 70,000 households in Los Angeles. Despite assurances by state and local health officials that the treated water would pose no health threat, local residents and their political representatives balked when they learned about the imminent startup in a series of local newspaper stories. New public hearings have been scheduled, even though the project was thoroughly aired during at least three phases of the planning and permitting process. Even the city's mayoral candidates have jumped on board, criticizing the lack of public involvement. "This is exactly the kind of issue that people have a right to make their own decisions about. It's their money, it's their water, it's their lives and they have to be consulted," Los Angeles City Councilman and mayoral candidate Joel Wachs told the Los Angeles Daily News. The resistance is not particularly surprising. The prospect of drinking former toilet water, no matter how much it has been purified by artificial and natural processes, generates what water managers refer to as the "yuck factor" — an almost insurmountable, visceral reaction that is not easily countered with testing data and epidemiological studies. However, there is nothing new or rare about the use of reclaimed wastewater in California. According to a September 1999 report by the State Water Resources Control Board's Office of Water Recycling, an estimated 364,595 acre-feet a year of municipal wastewater is currently being used. It is produced by 221 treatment plants, representing 45 of California's 58 counties, and is used at about 4,380 sites. By far the largest use is agricultural irrigation, which consumes 177,622 acre-feet a year. Landscape irrigation and impoundments rank second, at 67,776 acre-feet. Groundwater recharge, a category that includes the possibility of eventual residential use, is third at 38,489 acre-feet, followed by wildlife habitat, 27,174; industrial use, 18,418; recreational lakes and ponds, 17,854; and combating seawater intrusion, 10,141. Wastewater reclamation projects are particularly popular in semi-arid Southern California, which relies on imports for most of its municipal and industrial water supply. Imported water is expensive, and Los Angeles in particular has seen significant reductions in its supply. California, which uses of 5.2 million acre-feet of Colorado River water annually, will soon be cut back to its legal entitlement of 4.4 million acre-feet, with most of that extra 800,000 acre-feet to be subtracted from the Metropolitan Water District's supply. Recent court settlements have reduced the amount of Owens Valley and Mono Basin water available to Los Angeles by 10%. And deliveries from the State Water Project have been curtailed to prevent harm to endangered fish. Increasingly, reclaimed wastewater looks like a promising alternative to imported supplies. Already, 76 such projects are in operation in a six-county Southern California area: 19 in Los Angeles County, 16 in San Bernardino, 13 in San Diego, 12 in Riverside, 11 in Orange and five in Ventura. The rising cost of imported water has made reclaimed water economically competitive, despite the need for expensive treatment. The price of water supplied by the LADWP's East Valley Water Reclamation Plant will be about $500 an acre-foot; the MWD now charges $431 an acre-foot for drinking water. Still, the public needs convincing. As long as reclaimed wastewater irrigates golf courses, cemeteries, freeway medians, and pastures, or is pumped through industrial cooling systems, the public does not seem to care. What prompted the April backlash against the San Fernando Valley project was the likelihood that water sent down the sewer would eventually return via the kitchen faucet. Similar concerns helped torpedo a similar project last year in San Diego. A 1995 proposal to release treated wastewater upstream from a huge Miller Brewing Company plant in Irwindale prompted a similar outcry — along with a spate of jokes — which forced that project to be scaled back and redesigned. (Beer drinkers no longer need fear that the water they flush down their toilets will return to them in six-packs.) Nevertheless, residential customers throughout California already drink water that has passed through a municipal sewer plant, whether they know it or not. Some of that reuse is intended and is the result of carefully designed projects; the rest is what the Office of Water Recycling refers to euphemistically as "unplanned reuse." The latter consists of much of the State Water Project's supply, which is drawn from the Sacramento-San Joaquin Delta. Nearly every municipal wastewater plant in the Sacramento River watershed upstream of San Francisco Bay releases treated effluent into the river or its tributaries, and an indeterminate portion is pumped into the California Aqueduct. And water agencies throughout California pump groundwater that is a mixture of pristine sources and surface water that has percolated underground after washing over city streets, farm fields and other potential sources of contaminants. Still, there is something uniquely disturbing about the direct conceptual link between toilet and tap, as embodied by such projects as the LADWP's East Valley Reclamation Project. Water managers probably will never overcome the "yuck factor" entirely; if they hope to realize the promise of this largely untapped resource, they must either restrict its use to nonresidential customers or do a better job of enlisting the support of local politicians. Contacts: The WateReuse Association, (916) 442-2746. Lynn Johnson, chief of the Office of Water Recycling, (916) 227-4580. Los Angeles Department of Water and Power Public Affairs office, (213)-367-1361. Joel Wachs, Los Angeles city councilman, (213) 485-3391.