Our lawns don't require the very cleanest water to thrive.
U.S. households are water hogs. On average, each man, woman and child uses an average of 100 gallons of tap water per day. In fact, the United States consumes more water than any other country - even ones that are equally well developed, according to the U.S. Environmental Protection Agency.

So, where does all of a household's tap water go? Roughly one-quarter ends up flushed down the toilet. Nearly as much goes for bathing. Clothes washers use 8 gallons per person daily, and homes with garbage disposals and automatic dishwaters send another 4.1 gallons down the drain. And then there are plenty of outdoor uses. Nationally, lawn watering and swimming pools consume roughly 25 gallons per day on average, and car washing another 2.5 gallons. In contrast, cooking and drinking consume, on average, a mere 2 gallons per person daily.

These statistics disturb hydrogeologist Peter J. Schreuder, a Tampa-based water consultant who also teaches at the University of South Florida. He bristles at tap water used for purposes other than ingestion. Throughout much of the world, water is a tight commodity. Even in the United States, competing interests have been waging heated battles - usually in the courtroom - over rights to the nation's supplies of freshwater. Ironically, Schreuder observes, municipally delivered tap water never was intended as a source of irrigation water for gardens or slurry for food scraps entering garbage disposals. Nations began providing water to individual homes as a way to fight disease. Subsidizing the delivery of disinfected - and often deodorized - water was justified as a means of improving public health. However, he points out, that was before most people had toilets, much less showers and garden hoses.

In recent decades, with the advent of near-universal indoor plumbing and the availability of almost limitless household water, uses for the commodity have spiraled. And with this valuable liquid costing a mere $2 to $5 per 1,000 gallons, people have little incentive to limit wastage. Schreuder describes the mindset that continues to facilitate the use of drinking water for toilets as the "arrogance of affluence."

Don't get him wrong, Schreuder isn't saying that people shouldn't bathe or water their plants. He just doesn't think they need the cleanest of water to do so. He would let municipalities pipe in lower-quality water - perhaps containing currently unacceptable concentrations of arsenic or some other pollutants - through lines feeding household faucets. Their output could then be reserved for such domestic activities as cleaning floors or dungarees.

Water for ingestion should be thoroughly decontaminated.
When people want water for drinking or mixing into food, he'd have them go to the supermarket and pick up several gallons - much as they now stock up on milk, apple juice, or Perrier. Who knows, it might even lead to the commercial delivery of bottled water to homes several days a week. As families in the 1930s signaled their need for ice, we could all leave a numbered sign in the front window on those days when we desired a delivery. The number would tell the agent how many bottles to leave behind.

Currently, Schreuder notes, utilities wither at the idea of cleaning up the merest traces of the pollutant de jour, be it microorganisms, potentially toxic breakdown products of detergents and plastics, or excreted pharmaceuticals. Technologies do exist to rid water of all these nasties; the processes just seem to be prohibitively expensive when considering treatment for every gallon that's sent into household plumbing. With Schreuder's plan, these costly technologies could be reserved - and even used in new combinations - for the thorough decontamination of water that will be ingested.

And if the water were sold in jugs, regional bottling plants could supply many states, much as soft-drink purveyors do now.

Another approach is dual piping. Wisconsin's Commerce Department is proposing another variation on this theme. "The past practice of requiring potable water at every fixture would be discontinued," notes Lynita M. Docken in the agency's division of safety and buildings. Under a new proposed rule, only one faucet would have to dispense drinking water. At all others, access to potable water would be optional.

Some municipalities are finding it hard to clean up naturally contaminated water supplies to achieve the purity mandated under current law. That's proving even harder for individual homeowners who get their water from a private well, Docken notes. For instance, she cites state data indicating that an estimated 3.5 percent of the wells in at least two counties wouldn't meet the EPA's current 50 parts per billion limit on arsenic in drinking water. And that limit is being lowered to 10 parts per billion.

Under Wisconsin's new draft plumbing code, private-well users would be able to install two different water lines within a residence. One line would draw water directly from a well that might have high arsenic concentrations. This line could serve toilets, outdoor faucets and the basement washer. Another line, which draws water from a treatment system that removes most arsenic and other priority contaminants, would run only to sinks and maybe bathtubs and showers. Docken says that some people might even consider installing a third line to their showers with water that had received only partial treatment: It might remove only those volatile toxic compounds, such as radon, that could be released into the air, especially from hot water.

The trick would be to teach consumers how to distinguish the different systems within a home, Docken notes. Moreover, each plumbing line would have to show distinctive markings so that plumbers don't confuse them during home renovations. Currently, the proposed plumbing-rule change is close to reaching the commerce secretary's signature, Docken says, after which it would be open for discussion at a public hearing. If it survives any opposition, she says, it could become law by July.

This article is provided through the courtesy of Science News, a non-profit organization dedicated to advancing the understanding and appreciation of science. Visit them at www.sciserv.org.