Activity is humming at the Bull Run Filtration Project site in east Multnomah County, where a joint venture of water plant specialist MWH Constructors and construction giant Kiewit Corp. broke ground in early June

They’re working under a deadline imposed on the Portland Water Bureau by the Oregon Health Authority to deliver filtered water to customers by Sept. 30, 2027 — part of a settlement reached after the parasite cryptosporidium was repeatedly found in Portland’s water supply. Along with a complementary pipelines project, the entire endeavor is expected to cost approximately $2.13 billion.

It amounts to perhaps the costliest ongoing construction project in Oregon. (The recently completed Portland International Airport main terminal project had a similar $2.1 billion price tag, but the upcoming Interstate Bridge replacement project will cost far more).

When finished, the Bull Run plant will provide up to 135 million gallons a day of fresh water to about 1 million people.

The project is funded through bonds and customers’ payments. The bureau also secured a $726.6 million federal loan at a 1.89% interest rate, and it is in the process of closing a second loan through the Water Infrastructure Finance and Innovation Act program, spokesman Brandon Zero said.