Sodium carbonate — also known as soda ash — is delivered to equipment that reduces lead in Bull Run water for the city of Portland.

The Portland Water Bureau’s latest effort to reduce lead in drinking water is paying off, according to the Oregon Health Authority.

The water bureau invested $20.6 million in a facility in unincorporated east Multnomah County to make Bull Run water less corrosive. The Improved Corrosion Control Treatment Facility was completed in April 2020. Now, after two rounds of testing, the OHA agrees the amount of lead has fallen far below the level that requires further action under U.S. Environmental Protection Agency rules.

“This is the realization of years of work and important investments to reduce our community’s risk associated with lead in home plumbing,” said Water Bureau Director Gabriel Solmer. “The test results show us that those investments are paying off.”

Although scientists agree there is no safe level of lead in drinking water, utilities are not required to take action unless it exceeds the level in the lead and copper rule that was first issued by the EPA in 1991 to comply with the Safe Drinking Water Act. It is enforced by the OHA. The action level in the rule is 15 parts per billion. The two most recent water bureau test results were 6.1 and 7.7 parts per billion.

The tests were conducted in the spring and fall of 2023. The results were sent to the OHA, which agreed the treatment was working, calling it “optimized” in a Dec. 22, 2023, email to the water bureau from Kari Salis of the health authority’s Drinking Water Services division. In the email, OHA agreed the water bureau only needs to send test results annually from now on.

According to the water bureau, for most Portlanders, the risk of experiencing lead in their drinking water was already low. Unlike other places in the country, Portland never used lead service lines to deliver water to homes. All other known lead service connectors were removed from the water system by 1998.

However, between 10% and 15% of homes used lead solder to connect their copper pipes. Most were built between 1970 and 1985 and are largely concentrated in southwest and east-side neighborhoods. That lead could leech into drinking water. Those pipes are owned by the property owners.

Aware of the problem, the water bureau has been using a number of methods to reduce the lead leeching from the risky pipes, including adding chlorine to the water and advising homeowners to run their water a few seconds before drinking it. But lead levels in homes being tested spiked in 2016, prompting the OHA to direct the water bureau to take corrective action.

The result was a study that recommended making additions to the water bureau’s existing Lusted Hills Treatment Plant. They include two 50-foot-tall white silos that add sodium carbonate (soda ash) to the water, a large white tank that adds carbon dioxide, connecting pipes, and multiple computers and control panels that allow operators to change the pH and alkalinity of Bull Run water.