Georgia is blessed with plenty of cool, clean groundwater. About 95 percent of rural Georgians depend on it to supply their drinking water and farm needs.

If they're careless, though, they can let contaminants get into the water.

"The well's condition and nearness to contamination sources determine the risk to the water you drink," said Tony Tyson, an engineer with the University of Georgia Extension Service.

A water quality expert, Tyson knows a private well is a poor place to let down your guard. "A spill of contaminants near the well could pollute your family's drinking water supply," he said.

The most common problems in the rural water supply, he said, are poorly built wells that allow surface water into the well.

"That can be a serious problem when there's a concentration of any kind of contaminant near the well," he said.

Statewide, two contaminants are the most likely to show up in rural wells. "Bacteria and nitrates," Tyson said, can be released from septic systems, waste-storage areas, feedlots and animal yards in amounts that could contaminate your well."

The best way to keep an eye on water quality, he said, is by testing your well regularly. When you do, the problems you're most likely to find are naturally occurring minerals.

High levels of such things as iron and water hardness can cause staining and laundry problems. But they don't often affect your health. "They're just annoyances," he said.

Lead is another potential contaminant. It's almost never in the groundwater. But it can be a problem when acidic water passes through the plumbing in certain old houses.

Many people worry most about pesticides. But Tyson said they're way down the list of contaminants in Georgia. "They're hardly ever a problem in well water," he said.

Testing for them isn't often practical, since tests can cost up to $100 per compound. As a rule, test for a pesticide only if you have a reason to suspect it, such as a spill near the well.

"You can't have your water tested for every conceivable pollutant," Tyson says. "But some basic tests can tell whether you have other problems."

Your county Extension Service agent or health department can advise you on the correct tests to run.

Have your water tested often, Tyson said, if:

* Someone in the family is pregnant.

* Your family has unexplained illnesses.

* Your neighbors find a contaminant in their water.

* You notice a change in water taste, odor, color or clarity.

* Chemicals or manure are applied to fields within 500 feet of your well.

Then make sure you know what the test results mean.

"Contact your county agent or another water quality expert to interpret test results." Tyson said. "Many materials, including bacteria and nitrate-nitrogen, are naturally present in minor amounts in groundwater. Or they can vary seasonally."

The keys to safe water, he said, are to be careful around the well and have your water tested as needed. Not doing either could mean taking chances with your family's health.