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January 10, 2001
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Arsenic levels
GV area water firms await new EPA standards
By Garry Duffy
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The difference between a few parts per billion may seem infinitesimal, but it could translate literally to tens of millions of dollars in upgrade costs for area water companies if the federal government adopts the most stringent of new standards for allowable arsenic in drinking water later this year.
Or it could mean that Central Arizona Project water could someday soon be flowing from local faucets.
“The costs might vary. Nobody has a firm grip right now on what the costs might be,” Michael Weber, executive director for Community Water Co. of Green Valley, said recently.
Weber and officials of other area water purveyors are talking about possible new standards by the federal Environmental Protection Agency for allowable levels of arsenic in water supplied to customers.
The consensus of those water comp-any officials is that if the EPA adopts the most stringent of standards, 5-or-10 parts per billion (ppb) of arsenic in drinking water, the wells of the companies will not meet those standards.
“The minimum cost could be a couple of million,” Weber said.
The EPA is considering new standards for arsenic in drinking water, dropping allowable levels from the current 50 ppb. How small the eventual number arrived at is of acute concern to local water company officials.
Weber said Community has four wells serving about 8,000 households in the northern portion of Green Valley. Those wells contain average concentrations of arsenic ranging from 9-to-12 ppb, far below the current EPA standard but above what could be imposed by the federal agency if the strictest standards under consideration are adopted.
The potential cost to the company to install mitigation systems to meet such standards, one likely passed along in water bills to customers, could be up to $2 million per well.
Weber said the company could be forced to consider using Central Arizona Project (CAP) water in place of groundwater if the actual costs for mitigation for the toughest potential standards become a reality.
Community Water has an annual CAP allocation of 1,337 acre feet, he said. It has an option for an additional 1,521 acre feet a year from an unused agricultural source, he added.
There are 325,851 gallons in an acre foot, enough water to cover one acre to a depth of one foot.
Similar situation
Green Valley Water Co. would be in similar straits if the EPA adopts the most stringent arsenic standards, Manny Oros, company general manager, said Monday.
“It gets up into the millions very quickly,” Oros said, agreeing with Weber that the average arsenic level in area groundwater generally is above both the 5 ppb or 10 ppb standards possible under new EPA regulations.
Green Valley Water has two wells, which most recently tested at 12 ppb and 13 ppb for arsenic, Oros said.
The company, which serves about 3,800 customers in Fairfield Homes’ subdivisions, has an annual CAP allocation of 1,900 acre feet, which would not be enough to replace the 2,200 acre feet of groundwater pumped from the wells to customers annually, Oros said.
That would leave the company with few options other than installing equipment to remove enough arsenic to meet whatever federal standards are adopted, he said.
“It’s going to be a very big cost if they make it so low,” said Oros.
Oros asked what added costs would accompany new allowable arsenic levels.
“What do you do with it after you remove it?” he asked.
There also would be the costs of transmission lines and treatment facilities for CAP water, he said. The current terminus for the CAP is at Pima Mine Road.
Some water company officials are pressing for an interim standard of 20 ppb, which they say would cut allowable arsenic in drinking water more than by half, and prevent those purveyors, especially ones with small customer bases, from going out of business because they would not be able to pay for costly treatment equipment.
“We have been very opposed to it,” John Gay, president of the Las Quintas Serenas Water Co. in Sahuarita, said Monday.
The company serves about 500 households in the Santo Tomas area, and another 300 customers through a “stand-pipe” that provides water that is hauled to the Curly Horn and Wrangler ranch areas for residents there without wells, or with wells not reliable year-round.
No CAP allocation
The small company has no CAP allocation, making that supply of water an unlikely alternative in the event that the EPA adopts standards for arsenic that Las Quintas Serenas would not be able to afford to meet by retrofitting its infrastructure.
“You’re talking big money,” said Gay.
Gay said the potential federal standards are arbitrary, and are not based on data that accurately indicates that the public safety is at risk under the existing standards.
The company has three wells, which average arsenic content about the same as Community Water and Green Valley Water. Gay said the standard ultimately adopted by the federal agency will be critical in determining whether small water companies can survive.
The differences between 5 ppb, 10 ppb, 15 ppb, or 20 ppb may seem indescribably small to the public, but not to water company officials anxiously awaiting which standard the EPA eventually will adopt following a current 90-day comment period.
“It is very critical, whether they go to 5 ppb, or 10 ppb, or 15 ppb,” Gay said.
At 15 ppb, Las Quintas and other small companies would survive. At a lower standard, they might not.
Interchange Water Co. is a subsidiary of Sharpe and Associates, developer of Rancho Sahuarita, a master-planned community on 2,810-acres inside the municipality of Sahuarita.
The water company is to serve the entire planned community of up to 8,000 homes. Although it is not operational yet, company officials are paying attention to the potential impact of more restrictive standards for arsenic.
“We have been monitoring what the regulations might be,” Tim Ensign, of Sharpe and Associates, said last week.
Interchange Water does not have current data for arsenic levels in its wellfields, Ensign said.
“We don’t have a level of arsenic we’ve tested for,” he said, adding that if the EPA adopts standards significantly more restrictive than the current ones, the company, Interchange Water would have to respond with mitigation.
“We would have to assess the logistics of the impacts,” Ensign said, concerning whether the company would choose to use groundwater or alternate sources like CAP.
Parts per billion is a measurement indicating micrograms per liter. One ppb is the equivalent of one penny in $10 million worth of pennies.
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