PORTLAND, OR — A recent test for lead in 134 Portland-area homes known to have lead solder in their plumbing found 18 of those homes to have lead-in-water levels higher than is acceptable, according to the Portland Water Bureau.

The water bureau tests high-risk homes with lead plumbing twice per year to ensure lead levels remain below the action level of 15 parts per billion. Water bureau officials in a statement released Thursday said they are required to notify the public when more than 10 percent of high-risk homes are above the action level; and though there are few sources of lead in Portland's drinking water, the main source of lead is home plumbing; and although Portland is working to improve its corrosion control treatment, 18 out of 134 homes does equal 13 percent of those tested — leading the officials to issue the public notice. The tested homes reportedly receive water from the Portland Water Bureau, Burlington, Lorna Portland Water, Palatine Hill, Pleasant Home, Raleigh, Valley View and West Slope water districts.

Tests in Fall 2016 resulted in 12 out of 122 high-risk homes exceeding the acceptable lead levels, officials said. The Portland City Council on March 1 authorized the water bureau "to begin implementation of improved corrosion control treatment to further reduce the levels of lead in drinking water," officials said. "This decision was based on a corrosion control study indicating that additional treatment is the most effective means of further reducing lead in water from home and building plumbing." While lead is a common element in the environment, the most common source of lead in Portland's water comes from the corrosion of lead-based solder in older homes, officials said. The Bull Run Watershed, Portland's primary drinking water source, is reportedly treated to prevent such corrosion. Officials said the council-directed improvements are expected to be in place by Spring 2022.

"Ideally, all of our customers' household plumbing fixtures would be lead-free, but they aren't," Portland Water Bureau Director Michael Stuhr said in a statement. "This is why we are making improvements to our system to further reduce the potential for lead at our customers' taps."

On Oct. 25, students at Astor K-8 School began drinking from brand new fountains installed in early September. The water fountains at multiple schools were shut off in May 2016, officials said, following reports of unacceptable lead-in-water levels at several Portland Public Schools — a scandal that ultimately led to the resignations of three PPS officials, including the superintendent.

Astor is one in the first group of 15 schools to see its water infrastructure replaced as part of a $28 million fixture replacement project, officials said. The other schools reportedly include Lewis, Woodstock, Chapman, Skyline, West Sylvan, Atkinson, Richmond, Rose City Park, Sacajawea, Beverly Cleary/Fernwood, Applegate, Chief Joseph, Meek, and Hayhurst.