Aging U.S. Water Infrastructure Raises New Engineering and Legal Challenges

Aging water and wastewater infrastructure is creating increasingly complex engineering questions for communities, utilities, property owners, and legal professionals. Bonneau Dickson, PE, a licensed sanitary engineer with more than four decades of water and wastewater engineering experience, has examined infrastructure conditions involving water systems, sewers, wastewater treatment facilities, pump stations, septic systems, stormwater, and contamination through engineering and forensic investigations.

Much of the nation's water infrastructure was constructed decades ago. The U.S. Environmental Protection Agency (EPA) notes that much of the country's drinking water, wastewater, and stormwater infrastructure was built after World War II, while some infrastructure is more than 100 years old. The agency has also identified a continuing gap between the resources needed to maintain and renew water infrastructure and the funding available for those needs.

The American Society of Civil Engineers' 2025 Report Card for America's Infrastructure assigned a C- to drinking water, D+ to wastewater, and D to stormwater. The report identifies aging infrastructure, maintenance needs, funding challenges, emerging contaminants, and extreme weather as factors affecting water infrastructure performance.

As infrastructure ages, the engineering questions surrounding failures can become more difficult to separate from questions of design, construction, operation, maintenance, and system capacity.

Aging Infrastructure Can Create Complex Failure Conditions
Water and wastewater systems are made up of numerous interconnected components. Drinking water systems can include source facilities, wells, treatment plants, storage tanks, pumping stations, transmission mains, distribution piping, valves, and service connections. Wastewater systems can include collection lines, manholes, pump stations, force mains, treatment facilities, and discharge infrastructure.

Over time, these components may experience corrosion, deterioration, leakage, capacity limitations, mechanical problems, or changes in operating conditions. The age of a component alone, however, does not necessarily establish why a failure occurred.
A forensic engineering investigation may need to examine the condition of the infrastructure, its original design, modifications made during its service life, maintenance records, operating history, and the conditions that existed when the incident occurred.

System Capacity Is an Important Engineering Question
One issue that frequently arises in infrastructure disputes is whether a system was capable of handling the conditions placed upon it.

A wastewater collection system may have been designed around particular population, flow, or infiltration assumptions. A water distribution system may have been designed for specific demands and pressure requirements. Stormwater infrastructure may have been designed around particular rainfall and runoff conditions.

Actual conditions can change over time.
Population growth, changes in land use, increased flows, development, groundwater infiltration, rainfall patterns, or changes in operating practices may affect how an older system performs.

A technical investigation can compare original design assumptions with available information about actual operating conditions. This may include hydraulic calculations, flow records, pump performance, storage capacity, rainfall information, inspection records, and field observations.

Sewer and Wastewater Failures Can Affect Property and Public Systems
Aging wastewater infrastructure can create conditions that result in sewage backups, overflows, infiltration, inflow, treatment problems, or service interruptions.

A sewer failure may involve deteriorated piping, root intrusion, blockages, inadequate capacity, corrosion, maintenance conditions, or problems at a pump station. Determining the cause requires consideration of the particular system and the circumstances surrounding the incident.

Wastewater treatment facilities also depend on multiple mechanical, hydraulic, and treatment components. Problems with pumps, treatment equipment, process capacity, piping, controls, or other infrastructure can affect system performance.
Forensic analysis can help determine whether an observed failure is consistent with a particular technical cause and whether other factors may have contributed.

Pump Stations Present Multiple Technical Considerations
Pump stations are critical components of many water and wastewater systems. They must operate within specific hydraulic, mechanical, electrical, and operational conditions.

An investigation into a pump station failure may examine pump capacity, wet well conditions, controls, valves, force mains, electrical systems, corrosion, installation, maintenance, and operating records.

Bonneau Dickson's project experience includes more than 300 water and wastewater pump stations, including approximately 200 wastewater pump stations. This type of project history illustrates the range of technical components that may need to be considered when investigating pump station performance or failure.

A pump station incident can also affect other parts of a system. For example, a failure may contribute to a sewage backup or overflow, making it necessary to examine both the immediate equipment problem and the broader system conditions.

Septic Systems Require Site-Specific Analysis
Not all wastewater infrastructure is connected to a centralized treatment system. Septic and other onsite wastewater systems serve individual properties, developments, mobile home parks, and other locations.

Their performance can depend on system design, soil conditions, hydraulic loading, installation, maintenance, wastewater flows, and site use.

When a septic system fails, the presence of an older system does not by itself identify the cause. A technical investigation may need to determine how the system was originally designed, how it was installed, how it was used, and what site conditions existed during the failure.

The engineering analysis may include septic tanks, leach fields, mound systems, collection components, and other onsite wastewater infrastructure.

Aging Water Systems Can Raise Water Quality Questions
Older water infrastructure can also create questions concerning water quality and contamination. EPA research identifies aging drinking water, wastewater, and stormwater infrastructure as a continuing challenge, alongside concerns involving contaminants such as lead and PFAS. The agency also identifies extreme precipitation, flooding, sewer overflows, drought, and changing water demand as additional challenges facing water systems.

Water contamination investigations can involve multiple potential sources and pathways. Technical analysis may examine water and sewer piping, cross-connections, groundwater conditions, sampling information, laboratory results, system configuration, and historical activities.

PCE contamination investigations, for instance, may require consideration of dry-cleaning operations, sewer infrastructure, groundwater, pipe leakage, and contaminant movement.

These cases illustrate why infrastructure investigations may require more than an examination of the physical condition of a single pipe or facility.

Stormwater Infrastructure Faces Additional Pressures
Stormwater infrastructure has its own set of engineering challenges. Drainage systems, detention facilities, channels, culverts, pump stations, and other components must manage runoff under particular site and rainfall conditions.

The 2025 ASCE Infrastructure Report Card gave U.S. stormwater infrastructure a D grade. It also notes that maintenance and funding needs remain significant across water infrastructure categories.

Flooding investigations may therefore require an examination of drainage capacity, rainfall, grading, detention systems, maintenance, pump performance, and the configuration of surrounding infrastructure.

An engineering assessment can help distinguish between documented physical conditions and assumptions about what caused a flooding event.

Engineering Evidence Can Become Relevant to Legal Proceedings
Infrastructure failures can result in disputes between property owners, utilities, contractors, municipalities, developers, insurers, and other parties. Legal questions may depend on technical issues such as whether infrastructure met its intended design, whether maintenance was adequate, whether a system had sufficient capacity, or whether a particular failure caused claimed damage.
Forensic engineering can provide technical analysis for these questions.

The process may involve reviewing engineering drawings and specifications, examining construction and maintenance records, inspecting infrastructure, performing calculations, evaluating system capacity, and analyzing photographs or other evidence.
The resulting findings may be documented in an engineering report. Depending on the matter, an expert may also provide deposition or courtroom testimony explaining the engineering analysis and the evidence supporting the opinions.
Distinguishing Age From Cause

An important consideration in infrastructure investigations is the distinction between an asset being old and the reason it failed.
Age can be relevant to an engineering investigation, but it does not automatically establish causation. An older pipe may continue to perform properly, while a newer component can fail because of installation problems, design limitations, operating conditions, or other factors.

Similarly, an aging treatment facility may have multiple components with different conditions and remaining service lives.
Determining causation therefore requires examination of the specific evidence rather than relying solely on the age of an infrastructure component.

The Role of Engineering Records and Field Evidence
As infrastructure ages, historical records can become increasingly important. Original plans may provide information about intended design conditions, while later records may document repairs, modifications, inspections, operational changes, or previous failures.

Field observations provide another layer of evidence. Physical conditions can help establish whether the current infrastructure corresponds with available documentation.

When these sources are examined together, an engineering investigation can develop a clearer technical picture of how a system was designed, how it changed over time, how it operated, and what conditions existed when a failure occurred.

About Bonneau Dickson, PE
Bonneau Dickson, PE is a licensed sanitary engineer based in Berkeley, California, with many years of wastewater engineering experience and more than 25 years of forensic engineering and expert witness experience.

His project background includes water and wastewater systems, sewer systems, septic systems, wastewater treatment facilities, water treatment facilities, water and wastewater pump stations, water piping systems, stormwater infrastructure, and contamination investigations.

He has been involved in more than 100 forensic and expert witness cases concerning water, wastewater/sewage, and stormwater. His engineering experience includes design, project management, construction oversight, inspection, system evaluation, forensic investigation, technical reporting, depositions, and expert testimony.

Media Contact:
Bonneau Dickson, PE
2428 McGee Avenue, Suite 2
Berkeley, CA 94703
(510) 845-8625
Email: [email protected]
Website: https://bonneaudickson.com/