"What about my drinking water?"

Many residents expressed this worry last year as the controversy over lake discharges and wastewater permitting grew on the Calumet Region's Lake Michigan shoreline.

But independent testing commissioned by The Times shows Northwest Indiana water is safe to drink.

An analysis of several water samples shows the quality of tap water is roughly the same around various parts of the lake in the region, even in the more industrial areas of East Chicago and Gary.

The Times collected samples of tap water from 13 communities throughout Northwest Indiana, Illinois, Wisconsin and Michigan. Samples were taken from towns and cities that are home to top industrial polluters and from communities such as Crown Point, for comparison.

Samples were sent to Alloway Labs, a certified environmental testing lab in Marion, Ohio, and listed through the Indiana State Department of Health.

The samples were analyzed for materials commonly found in drinking water and those often discharged by industrial and municipal facilities.

All samples were tested for lead, nitrate/nitrite, arsenic, fluoride, nitrogen/ammonia, copper, mercury and zinc. The tests were approved by Michael Herlick, quality assurance officer for Alloway and a former member of the U.S. Environmental Protection Agency's Environmental Laboratory Advisory Board.

Herlick called the results of each sample "fairly representative of homeowner tests," with little difference in contaminant levels typically found in most tap water.

Is it safe?

None of the test results in the region are close to dangerous ingestion levels, Herlick said.

"Everything looks good," he said.

He called fluoride levels from all the communities "in good shape."

The water from some communities outside of the region tested at higher than optimal levels for certain contaminants, he said.

Nitrates from Chilton, Wis., for instance, tested at 23 parts per million, more than twice the federal drinking limit of 10. All other communities tested by The Times showed nitrates at less than 1 part per million in tap water.

Infants younger than 6 months who drink water in excess of 10 parts per million could become seriously ill, with symptoms of shortness of breath and blue-baby syndrome, environmental experts say.

Chilton residents and officials have acknowledged a nitrate problem. Chilton is home to Foremost Farms, a cheese plant where the release of more than 74,000 pounds of nitrates in 2006 placed it seventh overall among industrial water pollution sites operating within the lake basin.

Impurities

Aside from Chilton's potentially dangerous nitrates, all of the water collected by The Times tested at safe levels, Herlick said.

Zinc was high in Whiting, at 600 parts per billion, and in Kaukauna, Wis., at 590 parts per billion, Herlick said.

Zinc falls under national secondary drinking water regulations, meaning the EPA recommends standards for cosmetic or aesthetic purposes but does not force states to comply with the limits.

Above 5 parts per million, zinc creates a metallic taste in water, experts say.

Ammonia does not have a maximum level for drinking water, Herlick said, but he called levels in Hammond high, at 0.49 parts per million.

Portage and Crown Point were next closest, with both at least 0.4 parts per million.

According to the World Health Organization, natural ammonia levels in ground water are usually below 0.2 parts per million, and higher levels may show up in drinking water because of disinfection processes.

The levels commonly found in drinking water do not directly affect human health, the organization reports.

Mercury, a contaminant of concern among many environmentalists, tested at less than 0.2 parts per billion in all of the communities. The EPA has set a drinking water limit of 2 parts per billion on mercury.