Water tables in northern Utah have dropped dramatically, but consumers shouldn't panic despite water rationing in Lay-ton and Hill Air Force Base, a state geologist says.

During the past year, water levels dropped in 90 percent of wells that were tested between Willard and Bountiful, said Joe Gates of the Utah Division of Water Resources, which recently completed a study of groundwater conditions with the U.S. Geological Survey.While water levels in aquifers near Hill have dropped between 40 and 60 feet since the mid-1950s, pockets of water exist as far underground as 1,500 feet, Gates said.

An aquifer is an subterranean layer of porous rock or sand containing water.

"It's a serious problem in Layton and Hill, and I don't want to minimize it, but it's not catastrophic . . . it's not like everyone's running out of water," Gates said.

Hill officials last week limited base residents to watering their lawns once a week and banned the washing of vehicles after civil engineers called the level in three of the six wells on base critically low.

Hill crews are working to lower pumps and pipes another 200 feet to reach water in existing wells and construction on two new wells has been accelerated.

Two weeks ago, Layton City put restrictions on watering lawns, and South Ogden Mayor Lew Wangsgard and Roy Water Conservancy Sub-district officials last week urged constituents to conserve water.

About 30 major wells are located near Hill, the largest concentration in what the state calls the East Shore area between Willard and Bountiful.

Water levels dropped five to 12 feet between March 1987 and March 1988 in that area, while levels in Ogden plummeted between 12 and 26 feet during the same period.

Although the water is there, more people are being forced to lower pumps and pipes in wells that were dug decades ago to reach the supply, Gates said.

Water levels traditionally are at their lowest during the summer months because of heavy pumping in the spring and summer, he said.

The amount of precipitation in the region also has been below average the past two years, while water usage has increased, Gates said.

About 67,000 acre-feet of water was taken from wells in the East Shore area in 1987, an increase of 1,000 acre-feet from the previous year, according to the study.

Besides greater water usage, the current dry spell hasn't had an immediate effect on the levels in the aquifers, Gates said.

However, he said the levels could be lower next spring if dry conditions continue and little snow falls next winter.

The groundwater study also listed Roy, Clearfield, Layton and Hill as having the best-quality water in the area because of water tables fed by the Weber River at the mouth of Weber Canyon, Gates said.

North Ogden also has high-quality water from streams that flow into the city from the Wasatch Mountains, he said.

Ogden and Plain City have the poorest-quality water in the region, possibly because of isolated underground pockets from the briny Great Salt Lake seep into the water tables, Gates said.