Storage Tank Inspection: What to Look For and When to Act

Finished water storage facilities: elevated tanks, standpipes, ground-level reservoirs: receive less routine attention than pumps and treatment equipment because they have fewer moving parts and don't generate alarms when they start to fail. That's exactly why they need a systematic inspection program.

Exterior Inspection

Walk the exterior of each storage facility on a regular schedule: monthly at minimum. You're looking for:

• Evidence of seepage or staining on tank walls or the surrounding soil
• Condition of the coating system: chalking, peeling, rust staining, or bare metal
• Condition of the access ladder and any fall protection equipment
• Security of the access hatch: locked, sealed, in good condition
• Condition of the overflow pipe and screen
• Vent condition and screen integrity (bird or insect nesting is common)
• Any vegetation growing in contact with the tank

Document what you find. A written inspection record that says "tank in good condition" is worth less than one that notes specific observations: "coating chalking on south face, vent screen intact, overflow clear."

Interior Inspection

EPA guidance recommends interior tank inspections every five years. State requirements vary: some require more frequent inspection, some require licensed inspectors or underwater dive inspections for tanks that can't be taken offline. Check your state's specific requirements.

Interior inspections look for corrosion of the floor and walls, coating failures, sediment accumulation, algae or biofilm growth, and structural issues. A tank that shows significant corrosion at the floor: the most common failure point: may need cleaning and coating work before the corrosion penetrates the steel.

Mixing and Residual

Storage tanks create water age issues when turnover is slow. A tank that sits at near-full for extended periods will lose chlorine residual, particularly in warm weather. Check your residual at the tank inlet and at the distribution side regularly: a significant drop across the tank indicates stagnation.

If you have persistent residual problems in sections fed directly from a storage tank, evaluate your operating level. Cycling the tank through a larger range each day: drawing down further before refilling: improves mixing and reduces detention time.

When to Call for Professional Assessment

Interior coating failures, floor corrosion, or structural concerns visible from outside the tank should trigger a professional assessment. Coating restoration on a storage tank is expensive but substantially cheaper than emergency repair or replacement. Catching it early gives you time to plan, budget, and schedule a shutdown: instead of responding to a failure.