Apache Junction residents will see a jump in their water bills beginning next month to cover the cost of meeting tougher federal standards for arsenic content.

The Arizona Corporation Commission approved a 24.8 percent rate increase Tuesday requested by Arizona Water Co., which provides water to nearly two-thirds of the city's residents.

The utility asked for the increase to recover the cost of meeting a stricter Environmental Protection Agency limit on arsenic levels in water.

As a result, the average monthly residential customer bill will increase by $6.70, from $27.04 to $33.74, the company said.

The previous EPA standard for arsenic was 50 parts per billion, but the allowable amount was reduced to 10 parts per billion - roughly the same contamination as a few drops in an Olympic-sized swimming pool - with a deadline of January 2006.

Some utility companies, including Arizona Water, were granted extensions to upgrade their facilities.

Joseph Harris, Arizona Water vice president and treasurer, said the utility had to spend $14.6 million to build new arsenic treatment facilities.

"We simply had to recover the costs," Harris said.

The company will also impose a 23.7 percent rate increase on its customers in the town of Superior, and a rate increase for San Manuel is pending.

One Pinal County resident said he is unhappy with the decision.

Robert Skiba, who said he has closely followed the rate increase process, said the public should not have to pay for the EPA mandate.

"Most people don't know anything about this," Skiba said. "Why should only consumers have to pay?"

The company started notifying customers about the impending increase in September.

Arizona Corporation Commission Chairman Mike Gleason said customers would need to understand that the federal government did not provide any funds for its mandate, so the company had no choice but to raise rates.

"The only source of funds is the ratepayer," Gleason said, adding that there was not much room for public comment because the rate increase stems from a federal mandate.

The rate increase will offset only the capital costs, not the cost of operation.

According to the EPA, arsenic, a tasteless and odorless carcinogen, is morepervasive in Arizona and other Southwestern states than in the rest of the country.

It enters drinking water supplies from natural deposits in the earth or from agricultural and industrial practices and has been linked to cancer of the bladder, lungs, skin and kidney, among others.

Apache Junction Water Co., a city-operated unit that provides water tothe remaining one-third of city households, said there are no plans to increase rates.

Water District Director Frank Blanco said a study is being conducted to evaluate the need for an increase, but nothing is planned yet.