Safeguarding Sewer Infrastructure: Why Certified Coating Applicators Make All the Difference

Sewer infrastructure runs unnoticed beneath our feet until it fails—and when it does, the fallout can be swift and expensive. Corroded manholes, compromised lift stations and leaky or collapsed pipes can lead to environmental violations, public health concerns and skyrocketing repair costs.

The conditions in these networks are unrelenting: damp and often laden with hydrogen sulfide (H₂S), other corrosive gases and persistent groundwater infiltration. In such an environment, a misapplied coating or incomplete surface prep can bring about early system failures that no municipality or utility wants.

Formal certification in proper product selections and repair procedures can be the key differentiator in managing these critical assets. Crews trained and certified under the Sherwin-Williams Certified Applicator Program (CAP) receive just that, providing confidence that every step of the rehabilitation process—from substrate prep to final holiday testing—is carried out with accuracy and care.

Paired with specialized products and robust warranties, certified applicators help owners and specifiers achieve improved reliability, minimized maintenance and extended service life.

The Complexity of Sewer Infrastructure

Below-grade assets like manholes, wet wells and clarifier tanks encounter near-constant moisture, harmful bacterial activity, chemical exposures and physical stress. H₂S, for instance, can encourage microbial-induced corrosion (MIC), which is particularly damaging to concrete. 

When an asset is inadequately coated or lined, deterioration accelerates, often leading to infiltration, exfiltration and costly remediation. In extreme cases, a complete system failure can halt critical services and pose health and safety risks.

Surface preparation is the foundation for success. Contaminants and moisture must be removed, cracks and leaks sealed, and substrate pH stabilized before protective coatings or linings can effectively adhere. Owners often invest in high-performance materials, but the outcome depends on the level of expertise applied in the field—from that initial surface prep to the final inspection of applied protective coatings.

Why Skilled and Certified Coating Applicators Matter

To successfully rehabilitate deteriorated sewer collection assets, applicators must rely on an array of integrated skill sets, including the following.

Following Surface Prep and Product Selection Guidelines

Achieving a clean, properly profiled substrate is the basis for successful rehabilitation. Certified applicators are trained to pinpoint active leaks, stop groundwater infiltration, correct pH issues and choose coating systems that match specific environmental challenges.

Some jobs may call for a high-build epoxy or elastomeric polyurethane, while others may benefit from structural mortars. Certified teams will know what will work best, as well as when to include aggregates to achieve thicker, trowel-applied section repairs for structural reinforcement.

Applying Proper Thicknesses and Performing Holiday Testing

A premium coating becomes far less effective if it’s applied too thin or marred by pinholes (holidays). Certified applicators follow rigorous standards to ensure the final dry film thickness will meet specifications.

These teams rely on visual inspections and wet film thickness (WFT) readings during applications and spark (holiday) testing following curing to identify any small voids or pinholes in the applied material that could compromise the lining’s integrity. They can then apply additional material to address any deficiencies.

Choosing Flexible Versus Rigid Systems

Infrastructure with potential substrate movement sometimes needs a more flexible, high-build polyurethane. In other cases, rigid epoxy solutions with glass-flake reinforcement may be essential for chemical resistance.

Certified applicators understand how to balance these differing demands, rather than forcing one type of system onto every structure.

The Value of a Formal Coating Application Certification

The Sherwin-Williams CAP integrates specialized training, product knowledge and ongoing oversight. This approach helps municipalities and utilities avoid quality blind spots and delivers repeatable results in challenging sewer environments.

Applicators in this program complete hands-on instruction covering surface prep, application methods, equipment calibration and testing protocols. They also learn about emerging resin chemistries and best practices—and renew their certification annually to stay up to date. When a certified applicator takes on a project, the work may also be audited by Sherwin-Williams Technical Service teams from initial prep through final inspection, reducing the likelihood of rework and unexpected delays.

Another core benefit is the program’s single-source warranty. In sewer infrastructure, it is common for a manufacturer to provide such guarantees for the product alone, while any labor or installation issues fall outside the agreement. With a certified applicator, the warranty encompasses both the coating material and the workmanship. This arrangement simplifies accountability and often results in fewer disputes.

In short, the Sherwin-Williams CAP carries meaningful enforcement. If a contractor fails to meet established standards, the manufacturer can revoke that applicator’s certification—incentivizing high-quality work on every job.

A Certified Coating Applicator Success Story in the Bluegrass State

In Frankfort, Kentucky, the municipality’s sewer department manages assets across residential backyards, farmland and easements in wooded areas, many of which had never received protective linings. Deterioration and infiltration were rampant in roughly 175 manholes, some decades old and exposed to elevated H₂S levels.

A team of Sherwin-Williams certified applicators was awarded the rehabilitation contract. Crews used smaller single-leg spray equipment to navigate difficult terrain. For each manhole, they removed deteriorated concrete and contamination with high-pressure water blasting. Where damage was extensive, they rebuilt the substrate with rapid-setting mortar to restore structural integrity before lining the manholes.

The chosen epoxy system delivered thick film builds, low permeability and fast cure times. Careful WFT checks and holiday testing ensured consistent coverage. Field audits and final inspections confirmed that the project met all required specifications.

Upon completion, the city noted a substantial drop in infiltration-related issues, cutting treatment costs for the sewer plant due to the greatly reduced volume of unwelcome groundwater entering the system. Through participation with certified applicators, Frankfort received a comprehensive, single-source warranty, ensuring long-term confidence in the repairs.

Avoid the Pitfalls of Uncertified Work by Hiring a Certified Coating Application Expert

When municipalities opt for uncertified applicators, they may face the trouble of inadequate surface preparation that leaves behind hidden moisture or cracks that undermine lining adhesion. In addition, they may encounter coatings that are incorrectly chosen or insufficiently applied, causing them to degrade when exposed to high-sulfide conditions or ongoing structural movement.

Without a formal certification program backing rehabilitation efforts, owners also typically juggle separate product and labor warranties with murky lines of responsibility. Over time, these shortcomings can lead to repeated callbacks, emergency shutdowns and spiraling remediation expenses.

Who Benefits Most From Certified Coating Application?

By opting for contractors that have completed formal certifications, municipalities and utilities can benefit from greater asset longevity, fewer unplanned repairs and a reduced total lifecycle cost. Engineers and specifiers can also experience a more streamlined bidding process when CAP requirements narrow the field to vetted, manufacturer-trained contractors. 

In addition, applicators themselves can enjoy improved marketplace standing, access to project leads and comprehensive manufacturer support.

While not mandated everywhere, formal certifications are being recognized by owners for the benefits offered in terms of controlling risk and maximizing returns.

Confidence for the Long Haul 

Sewer infrastructure is both vital and vulnerable, and any lapse in application quality can lead to early failures.

Crews from the Sherwin-Williams CAP bring deep technical know-how, specialized equipment and on-site accountability, installing coatings that protect these structures for decades with confidence. Frankfort’s success story underscores how a well-trained team, matched with high-performance products and unified warranties, can deliver extended service life, minimized infiltration and lasting peace of mind.

Contact Sherwin-Williams to Find a Certified Coating Application Expert

Don’t take chances with your sewer infrastructure. Trust the expertise of Sherwin-Williams certified applicators to safeguard your assets for the long haul.

Contact us today to find a certified coating application expert near you.

ABOUT THE AUTHORS 

Paul Trautmann is Market Director for Water Infrastructure for Sherwin-Williams Protective & Marine. He has more than 30 years of experience in the paints and coatings industry working in various capacities and has authored technical papers related to protective coatings and presented educational programs for the Society of Protective Coatings (SSPC) Coatings+ Conference and regularly hosts educational luncheons for municipalities, industrial facility owners and consulting engineering firms. Contact: Paul.Trautmann@sherwin.com

Steven Roetter, P.E., is a Market Segment Manager for Water Infrastructure for Sherwin-Williams Protective & Marine. He has been with the company for six years. Prior to that, he was a consulting engineer in the water and wastewater industry for more than 35 years. His current geographic area of responsibility is the Western region of the United States and Canada. He is a professional engineer registered in Indiana and New York, an AMPP Protective Coating Specialist, a NACE Level II Coating Inspector and a Past President of SSPC: The Society for Protective Coatings. Contact: Steven.P.Roetter@sherwin.com