Standard steel heating oil tanks are strong and durable but, like most things, they eventually need to be replaced. Internal corrosion, caused gradually over time by natural condensation, is usually the reason. Most homeowner insurance and oil dealer service policies do not cover oil tank replacement. With our proactive annual TANK-GUARD® Oil Tank Protection Program, qualifying tanks are protected against damaging internal corrosion with an effective liquid corrosion inhibitor to reduce the risk of tank failure. Plus, you will be protected financially with a generous tank warranty if your tank should need to be replaced while it is registered on our program.

Why not call your heating oil dealer today to see if your tank qualifies?

TANK-GUARD® Program Details

Safety Inspection

An oilheat service technician will make an initial safety inspection to verify that your tank qualifies. We use visual inspection guidelines as recommended by the National Oilheat Research Alliance (NORA).

Corrosion Inhibitor Treatment

Your tank will be treated with our concentrated TANK-GUARD® liquid corrosion inhibitor during a regular oil delivery or service visit.

Oil Tank Warranty

If your tank leaks from internal corrosion while it is enrolled on the TANK-GUARD® Program, your oilheat dealer will arrange to replace the tank and you will receive a generous warranty credit toward the replacement cost. Your dealer can provide full warranty details and tell you the current amount of the warranty credit.

Automatic Renewal

Your TANK-GUARD® protection will be automatically renewed each year. You will be billed for the renewal, your tank will be treated annually with the TANK-GUARD® corrosion inhibitor and your warranty will continue uninterrupted.


Internal corrosion is the most common cause of oil tank failure. All heating oil tanks are vented to the outside atmosphere. Moisture condenses from the air inside the oil tanks – even indoor tanks. The moisture (actually a small amount of accumulated water) is heavier than oil and goes to the tank bottom where it forms an acidic sludge. Over time it can corrode the metal by oxidation (rusting) or electrolysis (pitting), eventually causing a leak. Leaks of this type typically start with slow seeping or dripping. Call your oilheat dealer immediately if you notice such a leak. Place a pan or container under the leak. Do not touch or wipe the area of the leak.

TANK-GUARD® corrosion inhibitor is a water soluble concentrate. It does not mix with the large quantity of oil in the tank. It mixes only with the relatively small amount of moisture and sludge in the tank bottom where it serves as a neutralizing agent and helps to impede further corrosion.

How does TANK-GUARD work?

Safety Tips

Check your oil tank regularly for any signs of a leak.

Call your oilheat dealer if you see oil anywhere on the tank, pipes, fittings or floor. Do not touch or wipe the area of a leak on the tank.

Consider placing a containment tray beneath the tank. It’s an inexpensive preventive maintenance precaution against leaks, drips or spills. See the example below.

Tank Tray

Unprotected copper oil supply lines buried in concrete can leak and cause contamination without being noticed. If your oil supply line from the tank to the burner is partially buried in concrete, make sure that it is encased in a non-metallic sleeve that extends at least 4 inches above the concrete at each end. If you’re not sure, ask your oilheat dealer to check it.

It’s a good practice to keep your tank full during the summer. Less space in the tank for air means less humidity inside the tank and less condensation and water accumulation over time.


“When my oil tank leaked, the TANK-GUARD® warranty covered most of the cost to replace it. Many thanks.”

Colebrook, NH

“I’m so glad my oil dealer suggested TANK-GUARD®. My tank leaked last week and the men who came to replace it were neat and very professional. My copay was only about $200 – paying for the whole cost myself would have been a real hardship.”

Cranston, RI

“I like feeling that TANK-GUARD® is good for my oil tank and that I have the warranty protection as well.”

Peabody, MA