Since 1997, the Portland Water Bureau has been adding sodium hydroxide to increase the pH of the drinking water to make it less corrosive. This treatment has resulted in up to a 70 percent reduction in lead in water levels at customer taps.
The Portland Water Bureau has consistently looked for ways to further reduce exposure to lead in water, such as removing known sources of lead from the system and adjustments to pH.
Most recently, on March 1, 2017, Portland City Council authorized the Portland Water Bureau to begin a Corrosion Control Treatment Pilot. This is the first step to implementation of improved corrosion control treatment to further reduce the levels of lead in drinking water.
The Portland Water Bureau recommendation was based on a corrosion control study to determine the main causes of lead in drinking water in our system. The results of this study indicated that additional treatment is the most effective means of further reducing lead in water from home and building plumbing.
The Corrosion Control Treatment Pilot will evaluate the different treatment potentials for effectiveness at reducing lead as well as other potential impacts to water quality and operations. This information will then guide the design and construction phases of the project.
The entire project is anticipated to take up to five years, with treatment in place by Spring 2022.