About 50 Utah water utility managers will be receiving notices soon that their systems fail to meet a new federal standard for arsenic.
"There is going to be a tremendous cost," said Larry Scanlan, a state Division of Drinking Water arsenic expert who estimates the cost of bringing the Utah utilities into compliance at about $63 million.
Nationwide, 5 percent of water utilities are expected to be out of compliance. Most of them are in the West. The cost of compliance could exceed $5 billion, making the new arsenic standard one of the most expensive drinking water regulations ever, according to the American Water Works Association.
For the Kearns Improvement District, removing arsenic from its eight tainted wells would cost about $1.7 million, or about $138 per household.
However, the cost in Delta could be $4.4 million, or more than $4,000 per household.
Where the money will come from is uncertain.
"There is a move afoot to petition Congress for money for those states impacted the most," Scanlan said. "They are talking about a special appropriation to help water systems in this area. That hasn't happened in any budget yet."
After years of debate and litigation, the EPA decreed that drinking water cannot have an arsenic concentration greater than 10 parts per billion. The previous standard, established in 1942, was 50 ppb.
Arsenic leaches into groundwater from some volcanic deposits and mining operations. The geology of the West makes this area particularly vulnerable to arsenic contamination.
In large doses, the compound can cause instant death. It also is known to cause cancer and harm neurological, immune, endocrine and cardiovascular systems.
Studies of large populations in Taiwan and Chile showed exposure to elevated levels of arsenic in the drinking water was associated with high incidences of cancer of the skin, bladder, kidney, liver and lungs.
Its health effects in smaller doses are lesser known.
Scanlan said ongoing studies of the health effects of low-level arsenic concentrations should have been completed before EPA lowered the health standard.
Environmentalists are pleased EPA finally toughened the arsenic rule, but say it still is inadequate.
"It's a step forward over the current standard but it's not where we want to be," said Paul Schwartz of Clean Water Action in Washington, D.C.