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Updated Residential Oil Storage Tank Regulations in Maryland: What You Need to Know

Oil Storage Tank Regulations in Maryland

Today l would like to discuss with you some updated residential heating and oil storage tank regulations in Maryland.

Oil storage tank regulations in Maryland affect both aboveground and underground installations. The Maryland Department of the Environment(MDE) is the government agency responsible for regulating heating oil, diesel fuel gasoline and other below ground and aboveground storage tanks. In mid-2022 the MDE updated the regulations for storage tanks and included in those updates were several things that changed that affect residential heating oil tanks. One big thing was not in the old regulations but now is, is that the MDE says all home heating oil tanks have to be installed per NFPA 31.


That is the “National Fire Protection Association” and they put out standards on all different types of things and each “section” or “book” has a number. With book #31 being “Standard for the Installation of Oil-Burning Equipment”. NFPA 31 is a standard for the safe, efficient design and installation of heating appliances that use a liquid fuel, typically No. 2 heating oil, but also lighter fuels, such as kerosene and diesel fuel. NFPA 31 applies to the installation of these systems in residential, commercial, and industrial occupancies. We will discuss residential heating oil tanks; Aboveground & Below ground.

So now that we have cleared that up lets let’s discuss the actual changes around oil storage tank regulations in Maryland. (I will save all of the long boring code speak and just put these rules in plain English for the purposes of this blog)


Basic single wall tanks if installed Outside have to be painted with a corrosion protectant. What this means is that these standard tanks (pictured below and are NOT painted, that is the factory primer)

now have to be painted when they are newly installed. The factory grey or black color is only a primer, and that now has to be protected. Upgraded tanks with longer warranties already have a corrosion protectant on them and you can tell by that color – either a beige or sand color, or have galvanized steel(which indicates double walled). (Of course some homeowners may paint their tank whatever color they wish so if you want to know what type of tank you have it is best to call us and we can help you with that.

275 gallon basic tank (grey)


330 gallon basic tank (black)


Any single walled tank (ie. Black or Grey) – the oil line HAS to come off of the bottom of the tank. It is no longer be an option to be in the top of the tank. This is to prevent water buildup in the bottom of the tank which corrodes the tank bottom and causes leaks. This rule does NOT apply to double bottom or double walled tanks.

Top of tank feed
Bottom of tank feed with a valve


All aboveground tanks must be sloped slightly towards the drain valve (oil tank valve in bottom of tank), this is also to prevent water and sludge from accumulating in tank


Outside aboveground tanks have to be secured the foundations they sit on. So what this means is the basic tank legs freestanding on the masonry lintels or concrete pads is no longer accepted. We now install a flange on the bottom of the tank legs and bolt that down so that way it secures the tank to the foundation it sets on.


Outside 275 gallon tanks have to be at least 5 feet away from property line. 330 gallon or larger tanks, have to be at least 10 feet from property line.


Tanks have to be installed at least 5 feet away from any open flame or furnace/boiler. Tanks also need to be 3 feet from an electric panel or meter.


For basement or indoor tanks, the fill & vent pipes have to slope from the outside wall back to the tank to allow all fuel to drain from pipe. Pipes cannot be level or have sags that would hold oil. So what that means is when you are REPLACING THE EXISTING BASEMENT TANK, if your old tank is located under the stairs, or in the center of the basement the location will likely have to change. The tank will need to be on an exterior basement wall or move to outside. Because if the tank is under the stairs, for example, we likely cannot install replacement tank and have the fill and vent pipes have slope up to the outside wall. If your tank pipes go thru another room above a finished drywall ceiling before they go outside, this is not acceptable. We would have to find another location to install your new tank.


when the basement tank pipes terminate outside, they have to be minimum 2 feet away from any opening to the building. And the vent pipe has to be high enough off the ground to prevent snow accumulation around it. Pipes also have to be made of steel.

PVC, plastic, or copper pipes must be replaced, even on existing old tanks.


If the tank is in the garage the fill & vent HAS to be run the outside wall, it cannot be filled inside or vented in garage. If tank is in traffic area, it has to have protective pipe bollards around it.


If you are located in a flood zone you will have to have a concrete pad poured prior to your tank being installed outside. Then we can secure tank to the concrete pad to prevent it from floating during a flood.


any newly installed underground residential heating oil tank must have cathodic protection coating & anode OR be made of fiberglass reinforced plastic. In short, this new rule means that any single wall steel tank must also have a secondary coating on the outside of the steel to protect it from corrosion. Or, tanks can be double walled. The 2nd layer is usually made of fiberglass or a plastic (polyethylene). 

This is not meant to be a comprehensive list of every rule in the book, just some of the big ones that (may have) changed in 2022. So Call Greentrax, Inc today to discuss your tank installation or replacement project.

PS. Do not assume your oil delivery company knows all the rules, they are oil delivery, not tank installer. Also your plumber or HVAC contractor probably does not know all these rules about oil tanks. You will be surprised that not all tank companies know all these rules either. But here at Greentrax we install hundreds of tanks per year and are residential tank removal and installation specialists.

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More To Explore

The Maryland Department of the Environment is cancelling the reimbursement fund for homeowners with leaking heating oil tanks!

This cancellation takes effect June 30th, 2024. You need to have your buried oil tank removed NOW, so if the tank is leaking you can get reimbursed for remediation costs before the program goes away. Click here for more information on the reimbursement fund as it operates now.

We urge everyone to contact their representatives in Annapolis and the Governors office and tell them DO NOT cancel the homeowner reimbursement fund for leaking residential oil tanks! They can still renew this program before this year’s legislative session ends.

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