Ameresco, Inc. completed Phase 1 of a multi-year citywide manhole rehabilitation program with the City of Mesquite, Texas this week. The project rehabilitated more than 190 manholes across a wastewater system that maintains approximately 6,400 manholes total. The work addressed visible signs of structural deterioration across the collection network, targeting one of the most common and underreported sources of sanitary sewer overflow (SSO) violations for mid-size municipalities.
What Inflow and Infiltration Violations Cost Municipal Wastewater Systems
Inflow and infiltration (I&I) is the entry of stormwater and groundwater into sanitary sewer systems through deteriorated manholes, cracked pipes, and failed joints. When wet-weather I&I flows overwhelm treatment plant capacity, utilities face SSOs that violate the Clean Water Act and can result in EPA enforcement actions, consent decrees, and fines. The American Society of Civil Engineers (ASCE) assigned U.S. wastewater infrastructure a D+ in its 2021 Infrastructure Report Card, with deferred maintenance and aging assets cited as primary risk drivers. During heavy rain events, municipalities with unaddressed I&I issues commonly experience a 20% to 50% increase in treatment plant flow volumes, according to EPA technical guidance, raising operational costs well beyond what rehabilitation would have cost over the asset's service life.
Manholes are frequently the lowest-cost and highest-leverage intervention point in a collection system. Their deterioration is visible, their rehabilitation is well-understood, and deferring the work does not lower the long-term bill. It raises it.
Mesquite Phase 1 Rehabilitation: Polymeric Lining, Grouting, and Structural Restoration
Ameresco's scope in Mesquite included a multi-layered polymeric lining system applied after thorough cleaning of each manhole structure. Any identified holes or cracks were grouted and plugged before coating installation to ensure maximum adhesion and long-term performance. The methodology is consistent with established rehabilitation approaches for concrete manhole infrastructure subject to hydrogen sulfide corrosion and groundwater infiltration. Phase 1 is the first component of a larger multi-year commitment. Mesquite's city manager described the program as a proactive cost management strategy, noting that rehabilitating assets before failure reduces both service disruption and long-term treatment costs. The city and Ameresco have an existing partnership that previously covered a smart metering infrastructure rollout for residential and commercial water customers.
Federal Funding Availability and the EPA Compliance Connection Heading Into Summer
The Infrastructure Investment and Jobs Act (IIJA) of 2021 allocated $11.7 billion through the Clean Water State Revolving Fund (CWSRF) specifically to help municipalities address wastewater compliance gaps, including I&I remediation. Despite available funding channels, many mid-size cities have deferred systematic manhole programs because the work lacks the visibility of large capital projects. EPA enforcement posture on SSO violations has tightened in recent years, with consent decrees increasingly requiring documented rehabilitation schedules as part of compliance agreements. Utilities entering the summer storm season without documented rehabilitation programs or active asset management records carry measurably higher inspection exposure than those that do.
