ePulse® Acoustic Condition Assessment: Helping Utilities Make Smarter Decisions About Aging AC Pipelines
Asbestos cement (AC) pipes were installed across North America from the 1940s to 1960s and today represent one of the highest-risk materials in water distribution networks. With more than 40% of AC pipes in places like California and Nevada now over 50 years old, utilities face a growing challenge: how to prioritize pipeline renewal with limited budgets, without waiting for failures.
Acoustic condition assessment is emerging as one of the most effective strategies to meet that challenge.
Why Acoustic Testing Matters
AC pipes often degrade through softening rather than losing physical wall thickness, making traditional assessment methods less effective. Acoustic technology, such as Echologics’ ePulse®, uses low-frequency sound waves to measure the structural stiffness of pipes from the outside with no excavation, no service interruptions, no water treatment impacts.
What acoustic testing provides:
- Identification of structurally weakened pipe segments
- Leak detection during the same assessment
- Average remaining structural strength or effective wall thickness
- Data to estimate remaining service life (when installation details are known)
EPulse's non-invasive approach helps utilities avoid premature replacement while ensuring at-risk pipes are renewed first, at a fraction of the cost of physical inspection methods.
How Three Western Utilities Are Using Acoustic Assessment
Fountain Valley, CA
Goal: Integrate real-world condition data into its asset management program.
Scope: 73 miles of pipe assessed over 5 years, including 6–10" AC mains.
Key Outcome:
- The city gained hard evidence to guide renewal decisions in four focus areas.
- AC pipe condition data now directly supports data-driven budgeting and prioritization.
Tacoma, WA
Goal: Improve capital spending efficiency while maintaining strong system reliability.
Scope: Part of a 4-year program assessing segments of 1,428 miles of watermains.
Key Outcomes:
- Tacoma cut its main replacement budget in half using more accurate condition data.
- Pipelines with adequate remaining life stayed in service, while critical segments were prioritized.
- Age-based replacement alone was no longer necessary; actual condition now drives decisions.
Sammamish Plateau Water, WA
Goal: Adopt proven technologies used successfully by neighboring utilities.
Scope: A 2024 pilot assessing 1.5 miles of 4–12" AC pipes.
Key Outcomes:
- The pilot validated acoustic assessment’s value within their network.
- The utility is now establishing an annual condition assessment program to guide renewals long-term.
Leaving a Legacy of Smarter Asset Management
Utilities across the Western U.S. are increasingly turning to acoustic condition assessment to make informed renewal decisions about aging AC pipelines. The benefits are clear:
- Proactive maintenance instead of reactive emergency response
- Avoiding premature replacement of pipes that still have useful life
- Prioritizing limited capital budgets for the pipes that need it most
- Identifying leaks before they become costly failures
- Supporting strategic decisions on when to rehabilitate vs. replace
AC pipes may be a legacy material, but with tools like ePulse®, utilities can make smarter choices, ensuring reliability while managing budgets responsibly.
