Portland Water Bureau (PWB) owns around 2,300 miles of water mains that are used to distribute potable water to the service lines, which connect the water mains with the buildings. This measure shows the failure (leaks and breaks) rate of water mains in the distribution system per 100 miles per year. This measure is widely used to highlight the condition of distribution systems. A high rate of failures indicates frequent service interruptions. This measure helps PWB determine the rate of water main renewals today and into the future in order to maintain an acceptable level of service by managing the failure counts at a level where the existing workforce can adequately respond. An increasing trend over a few years may result in the allocation of additional funding to replace and repair water mains.

The average value for this measure in the industry is around 16 (failures per 100 miles per year). Historically, the Water Bureau distribution system failure rates have been about half of this national average. This is generally due to more favorable soil conditions in/around Portland (in terms of the soil’s corrosive effect on metal pipes) and the fact that Portland’s water distribution system is relatively younger than other similar size or larger cities. The failure rate has remained relatively steady and the Water Bureau will continue to monitor this measure closely and use this information as input into adjusting future water main renewal rates. Over the last fiscal year, the Water Bureau overlaid the distribution of water main failures across its service area with the Social Vulnerability Index (per Centers of Disease Control and Prevention methodology), which is a metric used to bring an equity lens to infrastructure management. With this information, decisions for water main renewals are now considering the equity impact of service outages (associated with water main failures) on different segments of Portland’s population.

The calculation is based on the recorded count of water main failures within each fiscal year and the length of water mains for that same period. A failure includes both leaks and breaks in a water main. The calculation does not include failures associated with actions from third-parties, such as a contractor damaging a water main during a construction project.

American Water Works Association (AWWA) publishes an annual survey of participating utilities that includes an average failure rate of water mains. In 2023, the AWWA reported median was about 16 breaks and leaks for 100 miles of water mains. Portland Water Bureau (PWB) tracks water main break and leaks failures monthly and reports annually as part of the budget documents. Please visit the PWB website to contact us with any questions about this performance measure. 

Portlanders can report leaks or water service disruptions and problems to the water service emergency line at 503-823-4874, available 24 hours a day and 7 days a week.