FARMINGTON — Few cities in Davis County have ordinances to help protect drinking water from contamination, by prohibiting certain land uses.

To help remedy that problem, the Davis County Health Department plans to help cities protect drinking-water wells. Only three cities in Davis County now have ordinances that help city councils and planners decide where to allow certain types of activities. Fruit Heights enacted an ordinance earlier this year, and Bountiful and Layton also have protective ordinances in place.

The health department's goal is to create a model ordinance that the remaining 12 cities in the county can adopt. The ordinance would prevent certain land uses from happening too close to wellheads.

The ordinances generally create four zones, based on the time it takes for water to travel from the zone to a given wellhead, said Mark Jensen, a scientist with the Utah Division of Drinking Water. Cities should keep all development out of zone 1, which is about a 100-foot radius from the well.

Zone 2 reflects a 250-day travel time for water and can help cities with the placement of animal feed lots and septic tanks. Zone 3 helps regulate the placement of certain chemicals, which if spilled could affect the drinking water in three years.

Zone 4 helps regulate chemicals that would take 15 years to travel from the area to the well, Jensen said.

Lewis Garrett, director of the county health department, said it's difficult to protect wells, because even if a city has strong zoning ordinances to protect its wells from contaminants within the city, the well's recharge zone may lie outside the city's boundary, leaving the city powerless to enforce development that could affect its drinking-water supply.

"The Legislature has looked at it a couple of times but has failed to come up with a way to protect wellheads," he said.

The issue becomes thornier in Davis County, because conservancy districts own many of the 68 drinking water wells in the county and have no authority to create ordinances because they're not cities, Garrett said.

Dee Jette, an environmental health scientist with the county health department, said the contamination threat to wells is real.

One drinking-water well in Woods Cross was shut down in 1999 after tetrachloroethylene, also known as perchloroethylene, or PCE, was found in concentrations that the U.S. Environmental Protection Agency considers unsafe. The area is now under consideration for designation as a Superfund site.