Keep Water Out of Your USTs

Written by: Brian Pottebaum, Director of Training Services

Typically, April showers bring May flowers, which is wonderful for plant life. However, with the recent rain, flooding, and even tornados for some Iowa and Nebraska areas, these heavy showers can also lead to water getting into your underground storage tank system. That isn’t so wonderful. It is important that UST operators properly maintain containment areas and check fuel quality to make sure water is not entering the fuel storage tank.

Unintentional water intrusion in your UST can be detrimental and costly. Any water entering the UST system is considered hazardous waste or petroleum contact water (PCW) and must be disposed of properly.

Tank operators must check for water in the tank no less than once a month. If there is no electronic monitor and the tanks are being manually checked with a measuring stick, make sure to use water-finding paste to detect any water that has entered the tank. Whenever water is observed or detected in the UST system, it should be removed immediately. Water can enter the fuel storage compartment through a loose fitting, broken drain valve, or flooding.

Water intrusion can degrade the fuel quality and result in microbial growth, component corrosion, and ultimately system failure. Microscopic bacteria can grow in a moist environment and attack the entire storage system, including steel and fiberglass reinforced tanks, tank linings, elastomeric seals and hoses, low points in the piping, leak detectors, turbine pump components, filters and valves, including overfill prevention devices. Excessive water accumulation in ethanol blended tanks (such as E10, E15, E40) can also lead to the ethanol attaching to the water molecules, leaving two distinct layers in the storage tank, a gasoline-only layer at the top and an ethanol/water mixture along the bottom.

For 30-day walkthrough inspections, any water or liquid that is observed in spill containments must be removed immediately. These containment areas are designed to capture any spilled fuel during the delivery process. Additionally, make sure to replace any damaged fill caps and gaskets to keep water from entering the tank.

All secondary containment areas should be closely monitored and physically inspected at least once a year. Secondary containment is designed to be a temporary barricade preventing a release to the environment and are not designed for long term petroleum storage. Best management practices require these areas to be managed carefully.

Make sure tank vent caps are in place and appear functional. Rainwater can enter tanks through damaged or missing vent caps.

2894 106th St. Ste. 220 Urbandale, Iowa 50323