Calculating the remaining life of structures

Rethinking ‘useful life’

The post-World War II population explosion and Clean Water Act in 1972 unleashed an unprecedented period of water and wastewater system improvements in the second half of the 20th century. Today, much of this infrastructure is at, or near the end of, its useful life.

But what exactly does “remaining useful life” mean?

Most municipalities use standardized asset and risk management systems to identify if and/or when an asset will be repaired, upgraded, or replaced, with funding based on historical precedence and priorities set by perceptions. They decide whether to rehabilitate or replace based on asset age and current condition.

However, there are problems with this approach, including:

• It’s too narrow; age is just one factor that affects an asset’s lifespan.
• Location, use or change of use, operation, and loading conditions affect how quickly or slowly an asset deteriorates.
• It doesn’t consider how important the asset is to the system’s ability to function as intended.
• It limits an agency’s ability to comprehensively and optimally direct the use of funds.

Next page: Avoiding ‘too much too soon’