Sometime this fall, Mike Nivison plans to take a healthy swig of water that exemplifies everything you'd expect from a small resort town set high in a Western mountain range. The water will be cool, clear, refreshing. But it won't be pristine spring water pouring from some mossy crevice.

 Nivison is Cloudcroft's village administrator, and what he anticipates savoring will come from the village's drinking-water treatment plant - and, not too long before that, from its sewage treatment facility.

 Cloudcroft's will be one of the first wastewater systems in the nation to allow - or require, depending on your perspective - residents to drink treated wastewater that hasn't been naturally cleansed in a river or aquifer. It will be built entirely as a matter of necessity. At an elevation of more than 8,500 feet in southern New Mexico's Sacramento Mountains, Cloudcroft is high and, thanks to recent years of drought, dry.

 "A city like San Diego can go buy more water," says Bruce Thomson, a University of New Mexico civil engineer who has been helping Cloudcroft develop its new water system. "It's expensive, but they can. But Cloudcroft is simply out of water. Because they're at the top of the mountain, there's no new place to drill wells. They're at the top of the watershed. They don't have any other alternatives."

 Cloudcroft has only about 750 residents, but its population swells to a few thousand on summer weekends. All those people escaping the lowland heat - and drinking, showering, and flushing - can use more than a third of a million gallons of water on a single hot Saturday. But the village's major wells produce only about 150,000 gallons a day. To make up the shortfall, village officials have resorted in recent years to hauling water, which is expensive, inconvenient and energy-intensive.

 Nivison figured that Cloudcroft's only sure source of what he calls "wet water" - that is, usable liquid, rather than theoretical legal rights or hard-to-reach water that might be buried somewhere deep underground - was right at his feet, in the stream of effluent pouring from the village's wastewater treatment plant. With several million dollars in state funding and the help of engineers from two universities and a private firm, the village has been building a plant to purify that water. After conventional treatments that settle solids and utilize microbes to degrade or remove pathogens, the plant will use multiple filtration methods, including reverse osmosis, to remove chemical contaminants. Then the water will be sent to covered tanks and mixed with groundwater pumped from the village wells.

 After three or four weeks, the blend will be sent back through drinking-water treatment and distributed for use. The wastes squeezed out during the reverse osmosis process, meanwhile, will be concentrated in briny effluent, which the village will store for use in dust control on roads, fighting fires, and, possibly, for making artificial snow at the local ski area.

 And then the toilets will flush, and the sinks and tubs will drain, and the cycle will repeat again - and if Nivison and his collaborators are lucky, no one will think much about it.

"By any parameter you can measure - suspended particles, salts, bacteria, pharmaceuticals - the water from this process is going to be extraordinarily clean," Thomson says. "But you have to overcome the 'yuck factor.' It's not measurable, it's not quantifiable, but it's every bit as important as the particles you can measure."

 "All we've done is recycle the same water on this earth since the beginning of time,"

Mike Nivison says. "This is just a more controlled environment for doing the same thing. I do believe this will be our salvation."

 He's right, of course: Using water is fundamentally a matter of recycling. Mathematically, you can show that the liquid pouring from your faucet today probably contains some of the same water molecules that George Washington drank in 1776. Remember the water cycle diagram you saw in grade school: Two hydrogen atoms bound to one of oxygen precipitate from clouds as rain or snow, seep into the soil, transpire from leaves, get lapped up by animals, course through streams and rivers, and finally settle, temporarily, in the ocean, only to evaporate once again to start the cycle anew. The idea of reuse is central to our understanding of water - perhaps even a bit compelling, when it comes to sharing molecules with George Washington.

 It's a good deal less so when you're talking about wastewater of newer vintage, such as the stuff they're going to be cleaning up and drinking in Cloudcroft. As the West grows in population, though, and as climate change seems to be decreasing the reliability of some water supplies, some of the region's residents are reconsidering the notion that effluent is something to get rid of as efficiently as possible. Only a few are willing to go quite as far, yet, as Mike Nivison, but many are at least embracing the idea that wastewater is a valuable resource. What's happening in Cloudcroft, then, is a portent of what is happening, and what likely will happen, in other arid places.

 But the prospect of brewing your morning coffee with water that was recently washing greasy dishes or flushing a neighbor's toilet has many people uneasy, and not just because of what psychologists and water engineers alike call the "yuck factor." The water to be recycled may carry a host of pollutants, some recognized only recently. Among the most worrisome are endocrine disruptors, which pose potentially large but as yet incompletely proven health threats that are making some scientists very nervous.

 Twice in the last 10 years, San Diego city officials have proposed augmenting the city's drinking water supply with water reclaimed from the city's sewers - and twice, in 1999 and again last year, those plans have been shot down.

 It is a telling comment on the disjointed nature of much water management in the United States that San Diego has both a water-supply and a water-disposal problem. On the supply side, the city imports between 85 and 95 percent of its water from distant sources - specifically, from the Colorado River and the California State Water Project, which conveys water from Northern California to the state's dry southern half. Those sources have historically been reliable, but only up to a point. In 1991, during a severe drought, water project deliveries were on the verge of being drastically cut when the rains finally came; this year, water planners are asking users to make voluntary cutbacks. And current climate projections suggest that the flow of the already over-allocated Colorado River may decline significantly in the future.

 For wastewater disposal, San Diego relies on a water-treatment plant at Point Loma whose technology is antiquated. It discharges effluent that does not meet Clean Water Act standards into the Pacific. San Diego has a waiver from the federal Environmental Protection Agency allowing it to dump that effluent, but the waiver expires in 2008. The cost of upgrading the Point Loma facility to meet EPA standards has been estimated at $1 billion, and the city has yet to make plans to raise that money.

 As part of a settlement agreement stemming from a lawsuit by the EPA and environmental groups, San Diego agreed to reduce its effluent discharge into the ocean by building two plants to treat water for reuse in the city and its surroundings. Those plants are now capable of putting out 37.5 million gallons of reclaimed, non-potable water a day.

 Like many other municipalities in the West, San Diego sells some of its reclaimed water to buyers who use it to water golf courses, feed industrial processes, and flush toilets. It's distributed in a network of purple pipes to distinguish it from the potable water supply, and it's currently available at about a third the cost of potable water. The trouble is that the purple-pipe network amounts to an entirely new, parallel water system, and San Diego, like many other cities, hasn't extended it very far.

"It's expensive to pay for the distribution of recycled water," says Maria Mariscal, senior water resources specialist for the San Diego County Water Authority. "Installing purple pipe in new developments is OK, but retrofitting in established areas can be expensive."

 As a result, the city is able to sell only about a third of its recycled water capacity and is unlikely to meet its target, developed as part of the lawsuit settlement, of selling at least 50 percent by 2010.

 To figure out how to use more of the reclaimed water, the city Water Department conducted a study that recommended treating it intensively and returning it to the potable water system. The system would be like Cloudcroft's on steroids: 16 million gallons a day rather than 100,000. Using the treated water to supplement San Diego's drinking-water system at a single point would be much more cost-effective than piping the treated water to an entire network of dispersed users of non-potable water.

 Turning treated effluent into drinking water is a widespread practice. It's most commonly done when communities dump their effluent into streams and rivers, knowing that other users downstream will use the same water. But an increasing number of communities are reusing their own water. In Orange County, El Paso, Tucson, and many other Western communities, water agencies recycle by dumping treated effluent on the ground so that it can soak in and recharge aquifers. After that water's been underground for a while, it is then pumped up for drinking water use.

 San Diego's topography, though, doesn't lend itself to recharging water from the treatment plants into local aquifers. So planners proposed pumping the treated effluent into a reservoir that feeds the city's drinking water system. The city council's Natural Resources and Culture Committee agreed and forwarded the proposal to the full council. A wide range of stakeholders on a community panel agreed, too.

 "To me, this is a win-win," says Bruce Reznik, executive director of San Diego Coastkeeper, an environmental group that monitors coastal pollution. "You're discharging less into the ocean, and you're creating a local water supply that you otherwise wouldn't have."

But opponents exploded, labeling the idea with a visceral and unforgettable moniker of the sort no politician can afford to ignore. "Your golden retriever may drink out of the toilet with no ill effects," editorialized the San Diego Union-Tribune under the headline "Yuck!". "But that doesn't mean humans should do the same. San Diego's infamous 'toilet to tap' plan is back once again, courtesy of Water Department bureaucrats who are prodding the City Council to adopt this very costly boondoggle."

 Mayor Jerry Sanders came to much the same conclusion, announcing in July of last year that he would not support the reservoir augmentation plan. A year later, the City Council has yet to decide on any new wastewater reuse strategies.

 "It was certainly disappointing," says Jim Crook, a consultant who helped draft California's water-reuse guidelines in the 1970s and served on an independent task force evaluating the city's proposal. "It was a good project from a technical standpoint. We were very comfortable with what they were going to do. The reclaimed water would be of a higher quality than some of the raw water sources that are used now."

 That, indeed, is one of the principal ironies here: Before it could even be used for reservoir augmentation, the water would be treated to a higher standard than what San Diegans are drinking now. Water discharged from the North City facility has already been shown to be at least as clean as water in some of the city's reservoirs. If it were to be dedicated to potable reuse, it would be subjected to further intensive treatment, such as reverse osmosis, before being pumped to the reservoir.

Reverse osmosis uses pressure to force water through a membrane that allows water, but not most other molecules, to pass through. It's expensive and energy-intensive, but it is better than almost any other technology at taking almost all contaminants out of water. Using it would bring San Diego's erstwhile wastewater up to a much better quality than, say, the Colorado River, which receives the waste from hundreds of municipalities and industrial users by the time it reaches Southern California. Las Vegas alone discharges roughly 60 billion gallons of wastewater a year some miles upstream of its own water intake - a feat of urban engineering that would seem to prove that most of what happens in Vegas really does stay there. What happens in Sin City is fueled by prescription and over-the-counter pharmaceuticals, caffeine, sunscreen, synthetic compounds used in plastics and detergents, and even methamphetamines, say researchers who have found all that in Lake Mead's water.