Hard-water trend raises hard choices for Tucson

Cloudy water. White flakes in the teakettle. Spots on glasses and chalky residue on dishes.

More than 400 such calls have streamed into Tucson Water over the past 20 months.

Calls are rising along with the mineral content in city water. Tucson Water started blending mineral-rich Central Arizona Project water with groundwater a decade ago. As the CAP share of the water blend increases, levels of salty minerals rise.

This fall, the City Council will consider whether it should try to stop that trend by spending $350 million to $415 million on three treatment plants to hold down the water's mineral content to about 450 parts per million. That's a little less than their current levels.

If the city does nothing, mineral levels will ultimately increase by almost 35 percent to reach the natural level of Colorado River water. That would force consumers to pay more often to repair or replace hot-water heaters and other appliances and fixtures that can be damaged by buildup or corrosion from hard water.

Tucson Water and the city's water advisory committee recommend against building the treatment plants for now because of the cost. Malcolm Pirnie, a private consulting firm for the water utility, concluded that paying off the plants' construction costs and $10-million-a-year operating costs would raise the average household's water bill by $11 to $12 a month. Repairing or replacing fixtures would cost about $7 a month over time, the consultant concluded.

No matter what the city does today, the issue isn't going away, said three University of Arizona water-quality experts.

Tucson imports about 200,000 tons of salts annually via the CAP that will slowly find their way into the city's aquifer.

"There is no quick fix. The salt content in the CAP is high. If you leave it in the water, it causes problems. … What we really need is a low-cost technology that will take salts out of the water," said Ian Pepper, director of the UA's Environmental Research Lab. "But that's not the end of the problem. If you remove it from the water, what do you do with the salt?"

He wouldn't say which choice he thinks the city should make today, but Martin Yoklic, a UA research scientist, and Robert Arnold, a UA environmental engineer, support waiting for economic reasons.

"All the solutions to these challenges are expensive," Yoklic said, "and we don't have money now."

Fixtures' life shortened

The minerals most commonly found in Colorado River water, known as dissolved solids or salts, are calcium, magnesium and calcium carbonate. They can reduce the life of water heaters, evaporative coolers, faucets, garbage disposals, clothes washers and dishwashers, concluded a 2006 study done for Phoenix-area cities and the federal government.

A decade ago, the mineral concentrations in the blended city water were less than half the federal government's recommended drinking water standard of 500 parts per million. But they are projected to hit 600 parts per million in 2025 and 630 parts per million by 2050, said Jeff Biggs, a Tucson Water administrator.

Much of the Phoenix area already gets 650 parts per million, and many residents there complain about the taste of the water. In Yuma and West Texas, the mineral content is as high as 1,200 parts per million.

Already, a local plumber and an air-conditioning business owner say they're getting more calls related to the impacts of harder water.

"We've been seeing a lot more minerals in evaporative coolers," said Al Coronado, a plumber since 1981. "The cooler itself is not going bad. The water distribution system gets clogged up and the cooler pads become more calcified."

Because of the harder water, Coronado said he also sees more burst waterlines. And toilets sometimes don't function as well because they become calcified, which eliminates the toilet's swirling action, he said.

Jim Beard, who owns an air-conditioning business, has stopped installing tankless hot-water heaters because harder water means homeowners must service them more often, "and nobody does," he said.

Larry Cummings, owner of Arico Plumbing, and Ramon Rangel, owner of 360 Plumbing, said they haven't noticed major damage to fixtures. But their customers are bothered by calcium buildup on faucets, shower doors, shower heads and cooler pads.

No market for salt

If CAP water isn't treated, its salt eventually will reach the city's underground aquifer, UA's Arnold said. That's because water is sprayed onto plants, and water used indoors goes into sewage plants that discharge wastewater into the Santa Cruz River - where it seeps into the aquifer.

Over time, he said, our water could become salty enough that it may not taste as good and it could cause problems for irrigating crops and plants.

The salt buildup could also affect the future use of reclaimed water on golf courses, he said. The minerals in CAP water concentrate heavily in the wastewater used on the courses.

In Scottsdale, salts in reclaimed water have been high enough that golf courses complained it was retarding turf growth. The courses paid to expand a treatment plant to get good water.

If Tucson Water were to remove salts, it would have to build evaporation ponds to store the saline wastes, then scrape away solids every two years and haul them to a landfill, said Fernado Molina, Tucson Water's spokesman.

"We looked to see if there was any kind of market for the salt," Molina said. "In a cold climate we could sell it to de-ice roads. But there's no use for it here."

There no rush to make a decision, but in the next 10 to 15 years the city will have to build some kind of treatment plant, said Councilman Paul Cunningham, a Democrat.

"It's a balancing game between ensuring that we can deliver water at an economical price and that the water supply we have is safe and clean," Cunningham said.

Councilwomen Karin Uhlich, a Democrat, said many Tucsonans fear a repeat of the damage caused to pipes and fixtures when CAP water was introduced to Tucson in 1993. Molina said that's unlikely because the city has been gradually adding CAP water; In the 1990s, "We overnight opened the valves and a different type of water went through the system."

Councilman Steve Kozachik, a Republican, said he would vote against building mineral treatment plants because it would push water rates, which recently rose, even higher.

But if Tucson's choice is to pay now or pay later, it should just build treatment plants now, Uhlich said.

"Our ability to get low-interest rates for bonding might be better now than in the future," she said. "Why have our water quality shift to the lower standard if it doesn't make sense?"

Questions?

If you are a Tucson Water customer and have a concern or question about minerals in your water, call 791-4331 or email TW_Web1@tucsonaz.gov

Contact reporter Tony Davis at tdavis@azstarnet.com