home heating oil tank

Underground Oil Tanks

In the last month or so, I've run into a ton of misinformation regarding underground oil tanks. Early in the month, at the ASHI-WW training session, I got involved in a conversation with inspectors from western Washington. Apparently, there are companies on the west side that will remove the tanks and perform mitigation, for $5,000-$10,000. Discovery of an oil tank on a property there often kills the deal in a dispute about who mitigates the problem. By the way, keep in mind the size of those tanks. It's actually an important number. The second occurrence was on the Idaho side of the line. Similar deal, oil tank was present (and in use with a converted coal-burner now acting as the oil-fired boiler.) The agent was concerned because, in her investigation she had contacted the City of Moscow, who referred her to the Idaho Department of Environmental Quality (DEQ) and said that there were the folks that managed the decommissioning of underground oil tanks. Folks, any time the DEQ gets involved the price tag goes up. It's the nature of what they do. In this case though, the City of Moscow gave bad advice, the same bad advice that the Washington home inspectors have been getting.

First, a little history . . . .

Above Ground and Underground Oil Tanks

These tanks store the oil that is - or was - used to fire the furnace in the house. Depending on the region, these tanks could be above or below ground.  Above ground tanks made for easier monitoring but the home heating oil has a tendency to 'jell' in extreme cold so a means of keeping the oil liquid and flowing was a necessity. The above ground tanks were easy to deal with when the homeowner eventually converted from oil to gas or electric heating. Empty them out and haul them away.

Underground oil tanks poses separate issues.

There are thousands of unused underground residential heating oil tanks in existence and many still contain heating oil. These tanks are typically 300 to 500 gallons in size and made of 12 gauge steel (about 1/8 inch thick). They average about 30 years before corrosion makes them prone to leaking, but the life of individual tanks varies widely depending on the properties of the surrounding soil.

These tanks were often just abandoned in place, the only clues that theyA breather vent pipe and a fill pipe in a garden space away from the home.  still exist, a copper feed line, or a breather vent, or the fill cap. Most of the tank, ranging in size from 200 to 500 gallons, are hidden from view. Even the pieces above the ground on the exterior - the fill  pipe and breather vent - might be obscured by vegetation. In short, they can be really difficult to identify.

Under Washington State regulations, the home inspector is required to "Report any evidence that indicates the possible presence of an underground storage tank."


Myth 1 - The EPA regulates underground storage tanks so homeowners need to follow their regulations

This is the source of most of the confusion. Remember when I said to keep the tank sizes in mind above? Yep, they're important. The EPA regulates fuel storage tanks that are larger than 1100 gallons. Home heating oil tanks are specifically excluded statutorily from EPA regulation (with a large caveat that once the tank leaks and reaches a body of water, you've got a huge problem.) The EPA site has this statement - "Tanks used for the storage of heating oil for consumptive use on the premises where stored are excluded from federal UST regulations. However, state or local regulatory agencies may regulate these tanks."

Myth 2 - Washington State, Idaho State, Regulate Underground Storage Tanks

 They do - in exactly the same way the EPA does. Again, the threshold for both states for regulating UST's is 1100 gallons. The State of Washington has a handy little flyer that will lead you through the process. Quoting Washington State, "Neither the federal government nor Washington State regulates the use or operation of residential heating oil tanks."

Since I live on the border between two states, I get to check everything twice. Sure enough, Idaho has a similar flyer, a little longer (head for page 6 - that's where you'll find the stuff for homeowners) that expressly states. "Some kinds of USTs are not covered by these regulations: Farm and residential tanks of 1,100 gallons or less capacity holding motor fuel used for noncommercial purposes."

Myth 3- A leaking oil tank is a huge liability to the homeowner

This one is partially true but only under certain circumstances. I'm going to use the Washington State Department of Ecology answer for this one as it is the most straight-forward. You are not required to report minor spills or leaks. They specifically defined a minor spill as ". . . those that affect only the soil near the tank."

The point where liability becomes a major concern is when one of two events occur: first, the spill contaminates a water source, whether it is a natural body of water such as a stream, river, lake, or well; and, second, if the spill impacts a neighboring property and contaminates it. There are ways to manage these risks if you have underground oil tanks on your property. Both states maintain programs to assist homeowners with insurance that would likely be impossible to obtain otherwise.

Washington State has an insurance program for homeowners - it's free but not transferrable. Go to the Pollution Liability Insurance Agency to get the details.

Idaho has a similar program but it's not free. There is a $25 annual fee to access the services at the Idaho Petroleum Storage Tank Fund

Myth 4- My underground oil tank is not in use. I have to remove it.

Maybe, but probably not.

The places to check on exactly how you are obligated to handle a tank decommissioning are the local building department or the Fire Marshall's office. I'd contact the Fire Marshall first as they usually have a better idea of the local regulations than the building departments, especially in smaller locales.

You are required, if the tank has been out of use for more than 1 year, to decommission it.

You have two options for decommissioning. The first is removal and this is by far the most expensive option. The second is to fill and abandon in place. Let's look at both.

Removing the Tank

First, understand that this is generally not required by law. Most municipalities realize the expense involved. Also, tanks that were accessible in the past may be hard to reach with the necessary heavy equipment now that the neighborhood has filled in and the landscaping has matured.

Both state environmental department - DEQ in Idaho, Ecology in Washington - recommend this option. Their argument is that it is easier to identify leaks this way (which they will then likely make you mitigate at your cost!) and that some mortgage lenders or insurers will want the potential hazard addressed.  On the first point, they have a vested interest in the cleanup process.

The second is a case by case process. A properly decommissioned tank that has been fully documented to meet the applicable regulations probably will not trigger a problem for you in the loan process. The key is the documentation.

Leaving the Tank in Place

This is a popular method to handling oil tank issues due to the reduced cost.

First, a warning. You can't just leave the tank and not do anything. Old tank will rust and they are subject to floating out of the ground in areas with high water table and to collapsing from rust. Usually that collapsing is encouraged by an unsuspecting soon-to-be emergency room visitor when they walk or play above it.

Decommissioning underground oil tanks requires a few steps. The early steps are the same for removing the tank.

  1. Pump all remaining oil from your tank
  2. Clean out any sludge in the bottom of the tank.
  3. Remove or cap all lines.

Here things separate. With removal, you uncover, lift out, and check for contamination before backfilling.

Abandoning in place requires a non-compressible, leak-proof fill material. Commonly, we'll see a weak cement slurry, sand, or foam. Personally, I favor the weak sand slurry. It's the same material that many utilities use to backfill trenches for gas line, fiber optics, etc.

Before You Begin

Whichever option you choose, make sure you check with the local jurisdictions first. You will almost certainly need to obtain a permit in a larger city. Smaller cities and towns may not require it but check anyway. You may discover that they have useful information regarding soil structures and local hazards that will be helpful in making a rational decision.

Hire a company that specializes in underground oil tanks. Bob the local handyman is probably not your best option for this project. Check to make sure that they carry the appropriate licenses and that they are insured, both for the tank services they are providing and also for general liability for any damage they might accidently cause.

After You're Done

Maintain a paper trail of all the work that was done, by whom, in a file. To document decommissioning of the tank, the property owner should retain a copy of the any reporting forms used by the local municipality, any permits, as well as all receipts, certifications (including those of the contractor that you wisely verified), and written materials associated with the project.

Make a copy of the file for yourself, and when you place the home on the market, a copy for your Realtor.