Potable Water Tank Inspections

Warranty Inspections

Municipal Diving highly recommends conducting 11 month warranty inspections of potable water facilities that have recently been erected, re-coated or repaired. Identifying defects during the warranty period can save the owners significant expense and assign responsibility to the original contractor.

Some of the issues frequently documented during warranty inspections include:

• Coating defects
• tie-wire/rebar corrosion
• leaks
• structural issues
• spalling
• material defects in Hypalon or Polypropylene covers or liners.

EXAMPLE: In 2010 Municipal Diving identified “sagging” or “wrinkling” coating and an unidentified black residue on the interior of 4 re-coated steel tanks. The tanks were addressed by the coating contractors under warranty at no additional expense to the water district.

3 Year Maintenance Inspections

AWWA in M42 – Chapter 8 (rev. 2013) states: “Tanks should be washed out and inspected at least once every three years, and where water supplies have sediment problems, annual washouts are recommended”. In the almost 3 decades Municipal Diving has been working in potable water storage facilities, we’ve seen how routine maintenance and inspections can save owners a considerable amount of time and money.
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It is not uncommon to have previously unknown problems identified during routine potable water tank inspections. Coating failures, leaks in both concrete and steel facilities, corrosion issues, components in need of repair, root intrusion, animal remains, vandal intrusion and structural damage from seismic activity are just some of the issues identified by Municipal Diving during routine inspections. We have documented, on several occasions, reservoirs with significant leaks (30-250 gpm) that showed no evidence of water leakage in the under-drainage system.

Identifying needed service and repairs before they reach the critical stage can save tens of thousands of dollars and allows for budgeting to address these issues before they become major projects. Establishing a baseline of a facility’s condition can also help plan for future maintenance.
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EXAMPLE: In 2008, Municipal Diving identified critical corrosion on an internal overflow line. Failure of that line would have resulted in an uncontrollable leak, draining the 5 MG reservoir.