How Regular Tank Inspections Help Prevent Water Contamination

Water storage tanks must be inspected and cleaned on a regular basis to help maintain good water quality in the distribution system and to help extend the tank’s life. Regular tank inspections can also help to identify minor issues before they become major issues, which can cause health problems and lead to costly repairs or premature tank failure. Tanks that are not cleaned on a regular basis can cause contamination events that are harmful to human health or contribute to aesthetic complaints.

There are two basic types of inspection:

  • The wet inspections are usually performed by certified divers or remotely controlled vehicles (ROVs). The state usually requires a wet water quality inspection.
  • The wet inspection problems usually lead to dry inspection problems. Dry inspections are typically performed only to check coatings for structural damage and mil thickness, and steel tanks for gauge thickness. Please keep in mind that dry inspections necessitate the tank being drained and turned off. Dry inspections are typically three times the cost of wet inspections.

How often should a water system inspect and clean storage tanks?

The interval between inspections and cleanings can vary depending on the type of tank and the quality of the water. A water storage tank should be inspected at least every five years, or more frequently if required by the state. Cleaning and repairs should be addressed based on the tank inspection findings. Additional inspections are encouraged between maintenance intervals.

The majority of states do not certify tank inspectors. Before hiring any inspector, request a copy of a standard report that corresponds to the tank in question. Check to make sure the report is acceptable to the state regulatory agency.

With the upcoming 2017 water quality rules, it is best to hire only inspectors who can provide in-service temperature readings to identify stratification.


Circulation is essential for preventing stratification of water within a tank. As an aside, freezing of potable storage tanks should be avoided with proper circulation and water turnover.

Water is typically added to and drawn from the bottom of the water container via inlet and outlet piping. The water level rises when the fill rate exceeds the draw rate. When the draw rate exceeds the fill rate, the water level falls. If the fill and draw rates remain constant, the system is drawing the water that was just added. As a result of the lack of circulation, the water at the top of the container becomes stratified and stagnant. Furthermore, the chlorine that remains in stagnant water can deplete, allowing microbial growth as well as the development of tastes and odors. Adding mixers to your tank to help with these issues is a common and cost-effective way to prevent this.


Bacteriological testing must be completed before the tank can be returned to service, regardless of the method used. The presence of coliform bacteria in sample testing after disinfection indicates the presence of potentially harmful contaminants in the water.

Water analysis can determine whether or not microbes and bacteria in a water sample pose a risk to public health. Other contaminants, on the other hand, are visible from within the tank. Dirt, mud, sand, rust, and other elements or particles can accumulate at the bottom of a tank, covering an otherwise pristine white tank bottom with inches of sediment. If too much sediment settles in the pipes, the outlet pipes can also become clogged.

To discuss any of the concepts described here in more detail, our friendly and experienced customer service team can help. We offer tried and tested services around Houston, Texas and Longbeach, California.

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