Water officials dispute a study that says the "environmental stress" that Salt Lake City's population is placing on the city's water resources rates a rock-bottom rating shared by Philadelphia and New York City.

As in a similar survey two years ago, LeRoy W. Hooton Jr., director of public utilities for Salt Lake City, says that some of the conclusions of Washington D.C.-based Zero Population Growth are wrong because they are based on outdated federal government reports that don't adequately reflect the sources of the city's water.According to the study, Salt Lake City scored a 3.2 average in air quality, water, sewage, toxic releases and population change. A rating of 1 in the survey was best and 5 was worst. Salt Lake City's total score has drastically improved since it received a rock-bottom 4.75 in a similar 1988 survey, prompting local health officials to dismiss most of the ratings as inaccurate.

Twenty-six other American cities shared the same middle-of-the-pack score. No city in the survey had a better average score than 2.

"Increases in U.S. population are placing enormous demands on the environment," said Susan Weber, executive director of Zero Population Growth. "And most of that growth is occurring in metropolitan areas. As a consequence, the urban environment is deteriorating and residents are experiencing a diminishing quality of life."

Salt Lake City, the only Utah city in the survey, scored 2-3 in all of the categories except water. In that category the city scored a 5.

The city's air quality improved from a 4 to a 3 or "warning" in the most recent survey. Sewer treatment rose from a 5 to a 3. The new survey deleted an early hazardous waste site category and replaced it with a toxic releases category - based on releases of industrial chemicals, Salt Lake City scored a 3. And in the population-change category, Salt Lake City - one of the few Wasatch front areas to lose population during the last decade - scored a 2 or "good."

Zero Population Growth rated 204 cities with 100,000 and more residents and found Salt Lake City's water resources to be among the worst.

"Cities which scored a 5 have both shrinking supplies and polluted water resources," the report said.

Hooton said that the report is wrong on both counts.

He said said that the U.S. Geological Survey reports on which the organization based its ratings don't even examine the source of most of Salt Lake City's water - mountain watersheds. The city's water supply should also be adequate until 2010 with the completion of the Central Utah Project.

"The reports don't cover where 99.9 percent of the water comes from. For example, a good portion of the Wasatch canyons are fully protected and have high quality water," Hooton said.

Hooton said the studies look at the possibility of well-water contamination. Few Salt Lake City residents are supplied by wells, but those who are don't use contaminated wells.

Hooton also said that recent improvements in the area's sewer system aren't reflected in the "warning" rating.

Gayle Smith, director of the Bureau of Drinking Water, Utah Department of Health, said that the group apparently took data out of context to produce the low rating for water resources.

"They've misused the data. It doesn't speak well for their organization," Smith said. "Salt Lake City has one of the highest safe drinking water supplies in the whole United States both bacteriologically and chemically," Smith said.

Dave McNeill, manager of planning at the Utah Bureau of Air Quality, says he always has problems with national air quality comparisons because of the Wasatch Front's unique geography and weather.

For example, Washington D.C. never exceeds air quality standards, but also has few smogless days, he said. At the same time, Salt Lake City exceeds air quality standards, but has many more days with clear skies when the weather cooperates.