Drinking Water Storage Tank Inspection
This customer contacted us for a drinking water tank inspection service. Potable water for this commercial development is supplied by a private well. The water well pumps filled two 15,000 gallon concrete water storage tanks that were connected in series. The tanks are piped together at the bottom which equalizes the water depth. The system was designed to supply 23,000 gallons per day however the development currently uses approximately 4,000-4,500 gallons per day. Due to the lower-than-expected consumption, the Massachusetts DEP required the tanks to be filled to 40 percent capacity, which allowed frequent turnover of water within the tanks.
This video shows the underwater rover scanning the tank's bottom and sides.
The concrete water storage tanks were installed in 2012 and had not been inspected since the installation. There are canister filters and manganese/iron filtration at the pump station before the filtered water enters the tanks. There is a provision for future fire protection utilizing an 8’ ductile iron pipe which is presently capped. This modification would require a backflow preventer and MassDEP approval.
A close-up of the screen at the overflow pipe outlet.
During the potable water tank inspection, CommTank technicians found 16 dead rats at the tank bottom. CommTank’s STI SP001 certified inspector examined the tank configuration and found mesh screen, installed over the overflow pipe outlet, had been compromised. The pipe had been installed at ground level and the rats were able to bend the screen top and enter the pipe. The angle of the screen also prevented these rats from exiting the pipe once they entered. It is believed the rodents jumped into the water to find another exit and died. The customer was notified of the problem and they contacted the Massachusetts DEP for guidance on how to address the contamination within the tank.
Dan Hoag has worked in the environmental and tank storage industry for 16 years. Dan’s range of expertise includes designing systems for oil spill clean-ups, treating soil contamination through "in situ" oxidation and testing, and inspecting underground storage tank systems. As head of Marketing and Information Technologies at CommTank, Dan draws from field experience to write about fuel, water and chemical storage technologies, and the regulations that affect them. He has developed training courses in home inspection, underground storage tank operator, ultrasonic thickness and tank tightness testing. Over the past decade, Dan has published over 60 articles about industry trends and has documented commercial, residential, and environmental projects through illustration, videos, and photography. When Dan unplugs from technology, he spends his time backyard farming, hiking, and kayaking, while masquerading as a hockey player during the wee hours of the morning.