Aug. 16--Tacoma Water, by the end of the year, will recommend the installation of water treatment equipment and storage that could raise rates by as much as 20 percent over three or four years beginning in 2011.

This affects 160,000 residential customers in Tacoma, University Place and other parts of Pierce County, as well as businesses and cities on Tacoma's system.

The utility is facing dual pressures. First, it must comply with a new federal rule to ensure the drinking water is safe from cryptosporidium, a parasite that's been found only once in eight years in city water. The second is more complicated and involves the long-term health of water from the Green River, the source of most of Tacoma's water.

The city has two options. The utility is leaning toward recommending installation of the costlier and more complex one: a filtration system, which the utility has initially estimated will cost $140 million and result in an estimated rate increase of 15 percent to 20 percent. The other option is UV light disinfection, which the utility estimates could cost $70 million and result in an estimated rate increase of 5 percent to 10 percent. Utility officials believe a filtration system is a better investment.

"Filtration, nationally, is the standard for treatment of surface water. We are exceptionally fortunate to have gotten to 2009 without the need to filter our water," said John Kirner, Tacoma Water superintendent. "Right now we're seeing some regulations that will require us to take some action, so it comes down to how much are you willing to pay, and how much risk are you willing to accept?"

The Public Utility Board will decide which system to install and how to manage rate increases.

"If money were not an issue, filtration would be the way to go," said chairwoman Laura Fox. "But obviously because of the rate impact, there are other options we're exploring."

Fox said those options include variations of size and location for either filtration or UV that would target only drinking water, not the entire supply.

Kirner confirmed that the utility is exploring different sizes for each system, but on Aug. 5 he discounted the idea of targeting only drinking water.

"I hate to put a whole lot of hope into that one because I'd be very surprised if that proves feasible," Kirner said. "To do that would be terribly expensive -- more expensive than filtering the entire supply, I think."

The utility built the so-called second supply pipeline, which opened in 2005, for $220 million -- and the ability to put drinking water down one pipe and non-drinking water down another would require a similar effort, he said.

Still, the utility will take a look at the idea.

"We were requested by one of the major industries in town to look at this, and we will," Kirner said.

That industry, Simpson Tacoma Kraft, makes industrial-use paper on the Tideflats and is the single largest user of Tacoma water.

Dave McEntee, Simpson vice president of operational services and external affairs, said Aug. 6 that the company was interested in reducing any potential rate increase by assessing whether industrial water could be separated from drinking water.

Beyond that, conservation would remain the company's main focus.

"We lower our bill when we use less gallons," McEntee said.

'CRYPTO' CAUTION

Green River water flows from high in the Cascade Mountains to the main water facility northeast of Enumclaw, where it is treated before being sent to customers.

It's here that water is tested for things that aren't safe to drink. The latest bug that's gotten the attention of federal regulators is cryptosporidium, a single-celled organism that most commonly causes diarrhea. Both the parasite and the disease are known as "crypto." Most people have symptoms for one to two weeks, but they can come and go for 30 days. And that's in healthy people -- people with weak immune systems can die.

"In the 1990s, there was a very large crypto outbreak in Milwaukee," said Wendy Marshall, a scientist with the EPA's office in Seattle. "It sickened 450,000 and, depending on how you count the numbers, 50 to 100 people died. Milwaukee was doing what they were supposed to be doing, but (federal) regulations weren't as protective. We didn't know."

Since then, outbreaks of crypto have happened sporadically across the country, from Utah to New York to Texas.

Tacoma Water began testing for crypto soon after the Milwaukee outbreak.