Oregon Public Broadcasting

Portland's water supply in the Mt. Tabor reservoir.

Portland has battled the Environmental Protection Agency for years over the city’s drinking water. The feds have pressed the city to invest millions to treat the water in the Bull Run system.

City officials say it’s unnecessary because the water is “clean.” EPA wants proof, and the city offered it’s response Monday.

But the notion of “proof” is changing. To get a variance from the federal Safe Drinking Water Act, Portland water officials need to prove the water is clean. Without one, the city will likely have to build a $100 million treatment facility in Bull Run. The city is trying for the third time to convince the EPA that it should be allowed to test the water and prove it can meet EPA’s standards. This time around, the city has worked more closely with the EPA, and federal officials have gotten specific. The EPA has asked for tests of potential contamination spots in the watershed. Water bureau resource director, Edward Campbell said the feds also asked Portland to work up a computer model to track pathogens. “Based on EPA’s input, we’ve looked into and are working directly with the authors of a model from Australia that we would try to adapt to the Bull Run watershed," he said. But a letter the city received last week from the EPA says the computer models and other indicators of clean water won’t make much difference in the end. Instead, the EPA says a variance will depend entirely on whether cryptosporidium is found in one place: the raw water intake. Even if tests there found a pathogen not known to harm people – the city couldn’t get a variance. Campbell said officials are hoping for clarification from EPA. EPA officials didn’t return a call for comment. The agency’s letter says the additional research would help  determine overall water quality and track seasonal changes.  The city expects to spend more than $3 million by the middle of next year on the effort to obtain a variance from the federal government. Officials aren’t aware of the feds ever granting a variance like this before.