The Portland Water Bureau has been treating monitoring the drinking water for lead and copper since 1997
The Lead and Copper Rule, published in 1991, regulates how drinking water systems manage lead and copper in drinking water. It requires that large systems treat drinking water to make it less corrosive which will reduce the amount of lead and copper from household plumbing that dissolves in drinking water.
The Portland Water Bureau has treated the drinking water to reduce lead and copper since 1997. Routine monitoring is performed to monitor the effectiveness of this treatment. Improvements in the treatment are underway to further reduce lead in drinking water levels.