Can Flooding Affect Underground Heating Oil Tanks?

Flooding can saturate the soil around an underground tank, making the ground soft and unstable. The tank may shift or even float upward if the water table rises enough. That movement can strain the connected pipes and fittings, leading to cracks or separations.

Water can also enter the tank through the fill pipe or vent if floodwater covers those openings. Once inside, water settles at the bottom, since oil floats on top. Over time, that water promotes rust and corrosion from the inside out, which can weaken the tank walls.

• Check for signs of tank movement, like tilted fill pipes or displaced vent caps
• Look for wet spots or oily sheen on the ground above the tank
• Smell for heating oil near the tank area after floodwaters recede
• Inspect the fill and vent pipes for cracks or loose connections
• Watch for changes in how the heating system operates, such as sputtering or poor heat

After floodwater recedes, do not turn on your heating system until a professional has inspected the tank and lines. Floodwater may have pushed debris into the system or caused electrical issues. Using it too soon could create a fire hazard or push contaminated oil into your home.

Keep everyone away from the tank area until it is checked. If you smell oil fumes inside your home, open windows and leave the building. Contact a qualified professional and your local fire department if the odor is strong, and see a doctor if you feel unwell from the fumes.

If your area is prone to flooding, take steps to protect your tank. Make sure the fill and vent pipes are sealed tightly and extend above likely flood levels. Consider installing a water-resistant cover over the vent cap to keep rainwater and floodwater out.

Keep a record of your tank's location and any maintenance history. After any flood, even a minor one, have the tank inspected before using the heating system. Knowing your tank's condition ahead of time helps you respond quickly, especially in regions with wet winters.