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Portland water customers concerned about parasite found in Bull Run reservoir

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City switches to groundwater wells but says there's no health risk from cryptosporidium.

PORTLAND TRIBUNE FILE PHOTO - The Bull Run reservoir is the primary source of water to Portlnd and much of the region.Regional water districts and other water providers that buy water from Portland for their customers are worried about the potentially deadly parasite found in the Bull Run reservoir, the primary source of the city's water supply.

"We're very concerned about it and monitoring the situation and want to know what Portland is going to do," says Mark Knudson, director of the Tualatin Valley Water District, which provides Portland water to customers in unincorporated Washington County and portions of Beaverton, Hillsboro and Tigard.

Water district staff discussed the situation with Portland Water Bureau officials Monday, the same day the bureau announced it had switched its source of water to wells along the Columbia River. The switch happened just days after the bureau announced that cryptosporidium had been found in the reservoir six times since the beginning of the year.

Although water bureau officials insist the amount of crypto — as it's commonly called — is small and no person has ever gotten sick drinking Bull Run water, Knudson says his agency's board of directors is well aware that the parasite killed 104 people and sickened thousands of others in 1993 in Milwaukie, Wisconsin. The outbreak prompted the U.S Environmental Protection Agency to adopt a rule requiring cities with open water sources like Portland to treat for crypto.

Portland was granted a variance by the Oregon Health Authority in 2012 because water in the reservoir has historically been so clean. The variance requires the bureau to routinely test samples of water for crypto. None was detected until a Jan. 2 sample. Then other samples tested positive on Jan. 3 and 25 and Feb. 1, 7 and 8.

Testing determines when to switch

The Water Bureau has not decided how long it will rely on the groundwater wells. "Our process for making that decision is to continue to sample the Bull Run for cryptosporidium and gather information about these detections. With additional information, and in consultation with public health officials, the bureau will decide when to re-activate the Bull Run supply," says bureau spokeswoman Jaymee Cuti.

The health authority could require the Water Bureau to build a treatment plant at the reservoir to kill the potentially dangerous parasite. Five years ago, such a plant was estimated to cost $70 million.

In additon to the health risk, Knudsen says the Tualatin Valley Water District is also worried Portland could raise its water rates to finance such a plant.

The water district is building a water treatment plant along the Willamette River in Wilsonville and a pipeline to Washington County, which would enable it to stop relying on Portland water by 2026.

Suburbs treat for crypto

The Lake Oswego-Tigard Water Partnership used the opportunity to reassure customers their water comes primarily from the Clackamas River and is treated.

"The recently upgraded filtration system at our water treatment plant removes cryptosporidium and pathogens that may be detected in the Clackamas River water supply," the partnership said in a statement to customers. "Ozone, a powerful oxidant, also provides an additional treatment barrier to protect public health."

However, about one-third of Tigard receives its water from the Tualatin Valley Water District.

Spread by animals

Crypto can cause cryptosporidiosis, a respiratory and gastrointestinal illness. It can affect anyone, but is especially dangerous to immunodeficient people. Although the Water Bureau insisted Bull Run water was safe before the switch, it also advised customers with compromised immune systems to contact their doctors for advice.

Crypto is spread through animal feces. Because there are no domesticated animals in the Bull Run watershed, city Water Quality Team Manager Yone Akagi says wild animals are the most likely source of the crypto.

Heavy storms that hit the region this year may have washed more contaminated soil than usual into the reservoir, Akagi said.

Whatever the cause, the crypto findings required the Water Bureau to evaluate larger and more frequent water samples. Theoretically, that could increase the chances more crypto will be found in the samples.

The health authority is allowing the Water Bureau to continue collecting and testing Bull Run water for crypto, says spokesman Tony Andersen. But the health authority also is "working through a range of options for the future" in case the results exceed the allowable limit, he says.

That limit is 0.075 or more "oocysts" per thousand liters of tested water at the conclusion of the current one-year monitoring period at the end of the year. An oocsyst is a microscopic structure that proves the existence of the parasite.

If that limit is exceeded, the health authority will revoke the variance and set a schedule for the Water Bureau to install EPA-required treatment. The cost would be paid by bureau ratepayers, as was the recent cost to disconnect open reservoirs at Mount Tabor and Washington parks. That was done to meet EPA requirements to keep crypto, other microogranisms, viruses, and other contaminants out of public water supply systems.

The Columbia South Shore Well Field is normally used as a second source of water in the summer. It may take up to two weeks, depending on location, for groundwater to make its way through the distribution system to homes and businesses.

Who drinks from Bull Run?

Providers that buy water from Portland are: GNR Water Company; Green Valley Water Company; Hideaway Hills Water Company; Lorna Portland Water, LLC; Skyview Acres Water Company; Two Rivers Water Association; Lake Grove Water District; Pleasant Home Water District; city of Tualatin; Burlington Water District; city of Gresham; Lusted Water District; Palatine Hill Water District; Raleigh Water District; Rockwood Water PUD; Valley View Water District; West Slope Water District; Tualatin Valley water District; and city of Sandy.

The Lake Oswego Review and the Times papers contributed to this news story.