ROUGHLY a month from now, the Portland City council will decide whether to move forward with an expensive plant for treating Portland’s very clean water, or a really expensive plant for treating Portland’s very clean water.  

I’m guessing it will choose both.

This is purely unscientific, but sitting in on city council meetings, you get accustomed to seeing a glimmer in the eye of council members when they seize on something they like, and prick up your ears when they begin asking lots of follow-ups on one point or another. More often than not, those are trusty dousing rods pointing to future decisions.

On Tuesday, when council had its first formal hearing on how it’s going to treat the Bull Run water supply for the parasite cryptosporidium (often called “crypto”), there was plenty to divine.

The city’s facing two essential choices—at least as the issue is framed by Portland Water Bureau Director Mike Stuhr. Portland can treat its water system with ultraviolet light, at a cost of roughly $105 million. Or it can use a more comprehensive filtration system, which could cost $500 million or more.

We have until August 11 to decide.

There’s a lot to balance in this equation. At a time when the water bureau is building a seemingly endless stream of expensive shit—and therefore hiking up water rates—the UV plant is cheaper, and could be built in relatively short order. But it only does one thing: fry the crypto parasite.

Filtration is massively more expensive, and would take more than a decade to install. But there’s also an argument that it’s ultra-effective, and will better position Portland to comply with regulations as they pop up.

“If I was made of money... I would build a filtration plant and I wouldn’t think twice about it,” Stuhr told council on Tuesday.

But Stuhr’s not made of money, and neither are you. So after council members began talking about laying groundwork for a filtration system in coming decades, the water bureau director made a pitch: Build the UV plant and run it for 25 or 30 years until the parts begin to fail. When they do, move forward with filtration.

“I would have it in my head to put money away for a filtration plant,” Stuhr said. “When the time came for this [UV plant] to get a time-out because it’s too old, I have planned and I have designed” a filtration system.

It’s a compromise that seemed to set elected officials’ eyes a-glimmering, and as I said up top, I’m guessing city council will largely follow Stuhr’s lead. But let’s also acknowledge this is a head-snappingly fast pivot for Portland.

Until this year, this city peacocked and flaunted its clean water supply to no end. We were the lone system in the country to not be required by the federal government to treat for crypto, which lives in animal droppings, because we had no crypto.

Then this winter’s wretched rains washed scads of the stuff into the watershed, causing 14 positive hits from January to March. Suddenly, Portland’s unique federal hall pass is being revoked—even though we’ve not found crypto since March, and there’s no indication anyone’s health was jeopardized—and we’re not talking about cleanliness of our water as much. We’re talking about a $500 million, full-on filtration plant.

I don’t have much doubt we’ll get it, eventually. Whether it’s at all necessary is another matter.