Evaluating the Evidence: Why Longest-Lasting Coatings Are the Most Sustainable Choice for Water Tanks

Imagine you're considering a cheaper option now to save money upfront. While it might seem like a good deal initially, that saved money will soon need to be spent again, often plus more, to replace or maintain the cheaper product over time. On the other hand, investing in a higher-quality product initially may cost more upfront, but it can save you significantly in the long run by lasting longer and requiring fewer replacements or repairs.

The Link Between Service Life and Sustainability

Let’s break it down: A coating system that lasts 30+ years means fewer repaints, shutdowns, environmental impacts, and labor and material costs over time. That’s not just smart asset management—it’s sustainability in action.

Using life cycle analysis, our team compared the projected costs and longevity of various coating systems. It became clear that coatings with zinc-rich primers and high-performance coatings offer the best long-term value.

On the interior, a zinc-rich primer and high-solids epoxy system, applied at 22.5 mils dry film thickness (DFT), is projected to deliver 30 years of service life. On the exterior, a zinc/polyurethane/fluoropolymer system at 6.5 mils DFT provides similar 30-year performance, as validated by real-world case histories and accelerated laboratory testing.

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Why Case Histories and Testing Matter

Real-world performance isn’t something you can simulate alone in a lab. That’s why case histories are crucial. Our study combined field data from North American tank projects with rigorous testing, such as scribe tests under corrosive conditions, to demonstrate how zinc-rich primers significantly reduce undercutting and corrosion, regardless of the technology combined into a complete system.

Testing also revealed that assumptions of equivalency between different manufacturers or generic technologies can be misleading. Formulation matters. When a lower-performing product is chosen based solely on price, the result can be a 25% reduction in service life, which, over an 80-year asset life, can increase total coating costs by as much as 46%. Once you pick the best technology, select the best product in that category.

Download the study's findings below.

Coating Selection Is Asset Management

The American Water Works Association (AWWA) defines asset management as providing the required level of service at an acceptable level of risk with optimal life-cycle cost. Selecting a coating system is a major part of that equation.

Unfortunately, coating decisions are often made without a structured comparison of system longevity. That’s where our study offers a data-driven approach for evaluating options within the AWWA D102 standard, which includes 13 coating systems but little guidance on long-term performance.

By combining lab results with real-world examples, our paper delivers clear estimates of service life, enabling engineers and owners to make informed choices that align with sustainability and budget goals.

Tnemec- Proven Performance, Sustainable Solutions

The most effective method of asset protection requires the fewest interventions over the longest period. At Tnemec, we’ve shown that high-performance systems with zinc-rich primers and advanced topcoats can deliver 30+ years of reliable protection, making them the most sustainable and cost-effective solution for steel water tanks.

It’s not just about longevity. It’s about making decisions that protect your infrastructure, budget, and community’s future.

Want all the details?

Click here to download the paper: Separating Fact from Fiction: AWWA D102 Coating Service Life