Portland is building a new filtration plant to keep our water safe and abundant for generations to come. The new filtration plant will remove the microorganism Cryptosporidium and must be completed by 2027 to comply with state and federal water quality rules. The filtration plant will also remove sediment, organic material, and other potential contaminants, providing consistent high-quality drinking water and making the water system more reliable.

Building a filtration plant of this size takes about a decade to plan, design, permit, and construct. The Portland Water Bureau has already begun work on the initial steps and has made some key decisions about the future filtration plant.

Location

The new filtration plant will be located just outside the Bull Run Watershed in rural Multnomah County. Portland Water Bureau has owned the filtration plant property for decades and has been operating facilities in the area for more than 100 years. The filtration plant site was selected because it met the requirements—the site is at the right elevation to work with existing infrastructure, it’s owned by Portland Water Bureau, the facility is consistent with the site’s zoning requirements, and it’s large enough to provide a buffer around the facility and its neighbors. Portland Water Bureau is committed to being a good neighbor through planning, design, construction, and future operations of the new facility. Visit the Neighbor Information page to learn more about the filtration plant site and the good neighbor process.

Size

The new filtration plant will have a capacity between 145 and 160 million gallons per day (mgd). This capacity continues Bull Run as Portland’s main water supply, meets water demands on most days in most years, and manages costs by matching filtration plant size to expected water use.

Filtration Technology

The new filtration plant will use granular media filtration, where the water is filtered through natural materials (charcoal, sand, and gravel). This is a proven technology used at almost all the large filtration plants in North America. Granular media filtration is the lowest cost option that can provide the desired water quality. Granular media filtration also provides excellent water quality, is flexible in adapting to different water conditions and new requirements, and fits on the filtration plant site with room to meet future needs.

These investments in the future of Portland’s drinking water will be funded through business and residential customer rates and by borrowing money over time. Borrowed money will be repaid over many years so that the cost is shared by current and future customers.

Portland Water Bureau is committed to keeping water rates affordable by actively managing costs throughout the life of the project. We will continue to assist those who struggle to afford their bill through the expanded low-income assistance program. If you’re having trouble affording your bill, our Financial Assistance program may be able to help.