The rules in short

1. Monthly ground-level checkAs a minimum, unless MassDEP approves otherwise in writing, the tank and surrounding grounds get a ground-level exterior inspection every month, with a written, dated log available to MassDEP at any time (Chapter 8.1.22(2)). The MassDEP log itself applies to all finished drinking water storage tanks and structures, but not to a hydropneumatic tank or an in-ground clearwell (log, instruction 1). · MassDEP Guidelines for Public Water Systems, Chapter 8 Finished Water Storage (Rev 5-11)
2. Comment on every problemComments must be given for any answer that indicates a problem or an impending problem; photographs are recommended (MassDEP log, instructions 3 and 4). · MassDEP PWS Monthly Storage Tank Inspection Log (Rev September 2015)
3. No climbing neededClimbing the tank is not required for the monthly check; binoculars can be used for the top. Anyone who climbs must follow OSHA safety regulations (MassDEP log, note 1). · MassDEP PWS Monthly Storage Tank Inspection Log (Rev September 2015)
4. Annual roof inspectionEvery atmospheric storage tank in the distribution system is visually inspected once a year including the roof or top: manhole hatches, vent caps, screens and their condition, watertight seals, signs of vandalism, locks and other sanitary defects, with a written, dated log (Chapter 8.1.22(3)). · MassDEP Guidelines for Public Water Systems, Chapter 8 Finished Water Storage (Rev 5-11)
5. Interior and exterior every 3 to 5 yearsA thorough interior and exterior structural and coating inspection every 3 to 5 years by qualified, experienced personnel. Interior inspections can be done by a diver with vacuuming equipment, by robotic equipment, or by draining the tank to remove bottom sediment; emptied tanks require disinfection (Chapter 8.1.22(1)). · MassDEP Guidelines for Public Water Systems, Chapter 8 Finished Water Storage (Rev 5-11)
6. Keep 5 yearsAll tank inspections stay on file for MassDEP for at least 5 years (Chapter 8.1.22(5); log instruction 2). · MassDEP Guidelines for Public Water Systems, Chapter 8 Finished Water Storage (Rev 5-11)
7. Competent inspectorsAll storage tank inspections are performed by personnel the water system determines competent to perform them (Chapter 8.1.22(4)). · MassDEP Guidelines for Public Water Systems, Chapter 8 Finished Water Storage (Rev 5-11)
8. Roof safetyOn a tank roof, workers are protected from falls greater than 6 feet at all times, by a guardrail, a fall restraint system or a fall protection system (Chapter 8.1.14(5)). · MassDEP Guidelines for Public Water Systems, Chapter 8 Finished Water Storage (Rev 5-11)
9. Placing the head in a tank is entryA water tank is a confined space, and tank entry includes placing the head into the tank for a visual inspection (Chapter 8.1.14(7)). · MassDEP Guidelines for Public Water Systems, Chapter 8 Finished Water Storage (Rev 5-11)
10. TurnoverMassDEP recommends a 3 to 5 day complete water turnover as a starting point, with each storage facility evaluated on its own and given its own turnover goal (Chapter 8.1.6). · MassDEP Guidelines for Public Water Systems, Chapter 8 Finished Water Storage (Rev 5-11)
11. Back into serviceAfter cleaning, a tank is disinfected by one of the AWWA C652 methods; the record of compliance is the bacteriological test showing the stored water free of coliform bacteria (EPA Region 8 checklist). · EPA Region 8 Drinking Water Unit, Finished Water Storage Tank Checklist (2025-10)
12. Detailed checklistsFor detailed maintenance and inspection checklists, MassDEP refers to the AWWA M42 manual, Steel Water-Storage Tanks, and to its own monthly log (Chapter 8.1.22(6)). AWWA standards are not reproduced in this app. · MassDEP Guidelines for Public Water Systems, Chapter 8 Finished Water Storage (Rev 5-11)

Massachusetts guidance. Other states set their own inspection rules; ask your state drinking water program. The text of the guideline decides.

Sources

• MassDEP Guidelines for Public Water Systems, Chapter 8 Finished Water Storage (Rev 5-11)
• MassDEP PWS Monthly Storage Tank Inspection Log (Rev September 2015)
• EPA Region 8 Drinking Water Unit, Finished Water Storage Tank Checklist (2025-10)
• EPA Distribution System Issue Paper: Finished Water Storage Facilities (2002)