Oil Tank Removal After a Heat Pump Conversion in Maine
The heat pump went in, the boiler came out, and the tank stayed where it was. In Maine that is not a loose end, it is a deadline that started running the winter the oil stopped.
Maine's Shift From Heating Oil to Heat Pumps
Maine is still the most heating oil dependent state in the country, and it is coming off oil faster than any of them. The state’s own account of the shift puts numbers on it.
- Households heating primarily with oil fell from over 70 percent in 2010, to 62 percent in 2018, to 50 percent in 2024.
- The state passed 100,000 heat pumps in July 2023, two years ahead of its own target, and set a further 175,000 by 2027.
- Efficiency Maine’s Triennial Plan VI, adopted in April 2025, is expected to reach another 38,000 Maine homes.
Around Portland the picture is further along than the state average. The city is down to 26.7 percent oil heat and runs mostly on utility gas, while Cumberland County is 40.8 percent and Maine as a whole is 50.3 percent. The conversions have happened. The tanks have not gone anywhere.
Heating oil shares and heat pump targets from the Governor’s office, 30 September 2025. County and city fuel shares from ACS 2024 1-year, table B25040. Read August 2026.
The Twelve Month Deadline After a Heat Pump Conversion
For a buried tank, Maine attaches a timetable to disuse rather than to failure. A tank out of service for twelve months must be removed within sixty days, unless a written request to stay out of service longer has been approved by the Commissioner.
There is a second requirement people miss underneath it. The tank is a registered facility, and it stays registered until it is properly closed. Under the Department’s underground tank rules, Maine registers every underground oil storage tank regardless of use, size or product, and regardless of whether it is in service, so disconnecting a tank does not quietly take it off the books.
The mechanics of getting it out are on the underground tank removal page, and the narrow circumstances in which it can stay are on the abandonment in place page.
Twelve month and sixty day rule from 06-096 C.M.R. ch. 691 section 11(D)(1); return to service from 11(B)(3); registration from section 4(A). Read August 2026.
What Is Still Inside a Disconnected Oil Tank
A tank nobody has filled for three winters still has something in the bottom of it. Residual oil, water and sludge separate out and stay there, which is why a removal is not simply an excavation.
The oil line usually comes out with it. On a conversion the line runs from the tank to a boiler that is no longer there, so it is disconnected steel or copper in the ground with no purpose, and leaving it is what turns a clean closure record into a partial one.
Conversions on Rented and Inherited Portland ME Property
Two situations produce most of the tanks we are asked about, and neither involves anyone living with the problem.
The first is a landlord who put heat pumps into a let property, quite reasonably scheduled the work around the tenancy, and never got back to the tank. The second is an inherited house where the conversion was done by a parent years ago and nobody now knows when the oil actually stopped.
Both run into the same thing at sale. The removal itself is a day. The notice in front of it is ten business days. Working backward from a closing date, that is the number that matters, and it is the one people discover late.
Questions After Switching Off Oil in Maine
- I switched to heat pumps. Do I have to remove the oil tank?
- If it is buried, Maine's answer is generally yes. A tank out of service for twelve months has to be removed within sixty days of that point, unless the Commissioner has agreed in writing beforehand to let it stay out of service longer. If the tank is in the basement or outside above ground, no clock runs and the decision is yours.
- When does the twelve months start?
- From when the tank went out of service, not from when anyone noticed or from when you bought the house. For most conversions that is the last winter the boiler ran, which means the deadline has often already passed by the time the question gets asked.
- Can I keep the oil system as a backup?
- Plenty of Maine households do, and a tank that is genuinely still in service is not out of service. What does not work is leaving a disconnected tank in the ground and describing it as a backup: the rule is written around whether the facility is in use, and returning one to service after twelve months needs the Commissioner's written approval.
- Does Efficiency Maine pay for taking the tank out?
- Efficiency Maine's rebates are aimed at the new equipment. The money that goes toward tanks is a separate Department of Environmental Protection program, delivered through the Community Action Agencies and income tested, and it covers replacement and removal of above ground home heating oil tanks at owner occupied single family homes.
- What happens if I sell before dealing with the tank?
- The tank goes with the house and so does the obligation. A buried tank that has been out of service for years, with no closure record and no deed notation, is the version buyers price most conservatively, because nothing on paper says what the ground around it was doing.
Ask About a Tank Left After a Conversion
Tell us roughly when the oil stopped and whether the tank is in the ground or the cellar. That decides whether a clock is running at all.