A storage tank bleeding rust, leaking at a seam, or shedding concrete forces a decision — and the reflex answer, “replace it,” is often the most expensive one. Many tanks have a sound structure under a spent coating, where the right move is to renew the barrier, not the asset.
01 Start with a condition assessment
You can't choose between repair, reline, and replace without knowing what you're working with. A useful assessment looks at:
- Shell and structure — ultrasonic thickness, remaining metal, weld/seam condition, and (on concrete) cracking, spalling, and reinforcement or prestressing condition.
- Coating — dry-film thickness, adhesion (pull-off), and the extent of holidays, blistering, or undercutting.
- Appurtenances — nozzles, manways, roof, vents, and seals.
- Fitness for service — evaluated against the governing framework (API 653 for steel tank inspection and reconstruction; AWWA inspection practices for water tanks).
The output isn't a verdict — it's a map: which problems are surface, which are structural, and how much sound asset remains.
02 Repair: when the shell is sound and the damage is local
If the structure is healthy and the problems are confined — a damaged coating area, a leaking seam, a corroded nozzle, a failed seal — targeted repair is the lowest-cost path. Spot-blast and patch the coating, weld-repair the defect, replace the appurtenance, and the tank is back in service for a fraction of replacement cost. Repair is the right call when the damage is the exception, not the rule.
03 Reline: renew the barrier, keep the structure
This is the option owners most often overlook. When the structure is sound but the coating is at the end of its life — generalized but shallow corrosion, a spent lining — the tank doesn't need replacing; it needs a new barrier. A full interior reline with an NSF/ANSI 61 epoxy or polyurea system restores corrosion protection and resets the maintenance clock for decades, at a fraction of the cost of a new tank. This is exactly why a field-recoatable tank is such a long-term asset: the steel is the durable part, and the lining is renewable.
Replacement is one option — not the default. A structurally sound shell can often be relined for a fraction of the cost of a new tank.
04 Replace: when the structure — or the coating system — is at its limit
Replacement is the right answer when the assessment finds the structure compromised or the coating system un-renewable:
- Section loss — wall thickness below what fitness-for-service allows.
- Concrete distress — significant spalling, active reinforcement or prestressing-wire corrosion, or wire breaks.
- A non-renewable coating — glass-fused-to-steel can't be field-recoated, so at end of coating life the practical option is replacement of the system.
- Capacity or compliance — the tank no longer meets the duty or current code.
When the bones are gone, relining a failing structure only buys a little time at real expense.
05 The economics of the decision
The cost order is usually clear: repair < reline < replace. A localized repair is cheapest; a full reline is a planned, budgetable mid-life event; replacement is a capital project with the longest downtime. The trap is treating a coating problem as a structural one and jumping to replacement — paying for a new tank when a reline would have delivered decades more service. The assessment is what keeps that from happening.
06 A simple decision framework
| What the assessment finds | The right move |
|---|---|
| Sound structure · localized coating or component damage | Repair |
| Sound structure · coating at end of life (renewable system) | Reline / recoat |
| Sound structure · non-renewable (glass-fused) coating failed | Replace the system |
| Wall loss below fitness-for-service · active structural distress | Replace |
| Concrete: prestressing-wire corrosion or breaks · major spalling | Replace |
| Capacity or code no longer met | Replace (or supplement) |
A corroding or leaking tank isn't automatically a replacement project. With a clear condition assessment, most aging tanks sort cleanly into repair, reline, or replace — and the middle option, relining a sound shell, is the one that most often saves the owner a tank's worth of capital.
TanksandCovers.com performs the condition assessment and supplies the repair, relining, and replacement solutions to act on it.