Oil tanks and soil contamination when buying a home: documents, BBR and liability

When you buy a home, the task is to make three things fit together:

1. What the registers show

2. What the documents say

3. What is physically on the property

An old tank does not automatically mean the soil is contaminated. Conversely, a registration as decommissioned does not mean the soil has been investigated and declared clean.

In brief

• The Danish Building and Housing Register (BBR) contains information about oil tanks, but the information is based on, among other things, owners' own reports and cases handled by the authorities.^[1]
• A tank can be decommissioned (sløjfet) either by being removed or by being emptied and sealed off in accordance with the rules.^[2]
• When a tank is permanently taken out of use, the owner must notify the municipality of how it has been decommissioned.
• The current owner can be obliged to decommission an old tank correctly, even if a previous owner failed to do so.^[3]
• Decommissioning does not in itself tell you whether there is oil in the soil.
• V1 mapping means contamination is suspected. V2 means contamination has been documented.^[4]
• Active domestic oil tanks (villaolietanke) have mandatory liability insurance when the scheme's conditions are met. Illegal or over-age tanks can cause problems with cover.^[5]
• Liability, insurance and any claims against the seller depend on the specific situation and agreement.

Why does the oil tank matter when buying a home?

An oil tank can have a bearing on:

• Whether the tank may still be used
• Whether it has been decommissioned correctly
• Whether the registration in BBR is accurate
• The risk of oil in the soil or groundwater
• Insurance cover
• The financing and valuation of the home
• Later building projects and soil removal
• How liability is divided between buyer and seller

That is why the tank should not be assessed only as an old heating system. It is a physical installation, a registration matter and a possible environmental matter all at once.

Active, decommissioned, sealed off or removed

The words mean different things.

The Danish Environmental Protection Agency (Miljøstyrelsen) describes two main ways of decommissioning a tank: it can be removed, or it can be emptied, have its filler pipe and vent pipe removed and be sealed off so that it can no longer be filled.^[2]

A buried tank that has been correctly sealed off may therefore remain in the ground. That is not the same as it still being in use.

What does BBR tell you?

BBR can contain information on, among other things:

• The tank's location
• Size class
• Material
• Year of manufacture
• Operating status
• Method of decommissioning

BBR is a basic data register. The information must reflect the actual physical conditions, and the owner is obliged to have errors corrected. Much of the information comes from owners, their representatives or cases handled by the authorities.^[1]

BBR is therefore an important starting point, but not a physical inspection.

BBR shows a decommissioned tank

This may mean that the municipality has received a notification of decommissioning. It does not necessarily document:

• That the tank has been dug up
• That the work was photographed
• That the soil was investigated
• That there has never been a leak
• That all old filler pipes have been removed

BBR shows no tank

This does not mean with certainty that there has never been a tank. Also look at the house's previous form of heating, building case files, old drawings and physical traces.

BBR shows a tank in use

In that case it is relevant to clarify its age, type, location, tank certificate, pipework and insurance, and whether the information still matches the actual heating installation.

Documents that can shed light on the tank

The tank's history may be spread across several documents.

A complete picture can be built from:

• The BBR notice (BBR-meddelelse)
• The property data report (ejendomsdatarapport)
• The tank certificate (tankattest)
• The municipality's tank records
• Notification of installation
• Notification of decommissioning
• Invoice from the company that emptied or removed the tank
• Photos from the excavation or sealing off
• Receipt for disposal of the tank and residual oil
• Drawings showing the tank's location
• Previous building case files
• Environmental reports and soil samples
• Soil contamination certificate (jordforureningsattest)
• Information from the seller

A tank certificate typically describes the manufactured tank and its data. It is not in itself proof that the tank was later installed, maintained or decommissioned correctly.

An invoice with the text “decommissioning of oil tank” can be relevant, but it is still useful to see exactly what the work involved.

Age limits for tanks under 6.000 litres

The Danish Environmental Protection Agency has set decommissioning deadlines according to location, material and construction.^[5]

The table is an overview. Special tank models may be subject to other or earlier deadlines. The Danish Environmental Protection Agency highlights, among other things, older spherical plastic tanks from a particular manufacturer as a separate issue.

If the year of manufacture or the tank type is unknown, the table cannot be used directly. The municipality can tell you what documentation it has registered and how the matter should be handled.

Who must arrange decommissioning?

When the use of an oil installation ends permanently, it must be decommissioned.

If, after the handover, a buyer discovers an old tank that a previous owner should have decommissioned, the current owner is still obliged to have the installation decommissioned in accordance with the regulations.^[3]

Whether the new owner may have a claim against the seller because of the information provided or the purchase agreement (købsaftale) is a separate question. It depends on the specific sale.

The duty to decommission concerns the tank. Any liability for soil contamination must be assessed separately.

Insurance for an active domestic oil tank

For domestic oil tanks under 6.000 litres, liability insurance is mandatory.

The insurance is often included automatically when the heating oil is supplied by an oil company that is part of the oil industry's scheme.^[5]

Cover requires, among other things, that the tank and pipework comply with the rules. If the tank is too old or does not meet the requirements, the insurance company may refuse cover.

With an active tank, it can therefore be relevant to know:

• The supplier of heating oil
• The policy or information about the collective scheme
• The tank's age and type
• Whether the pipework meets the rules
• The most recent delivery
• Any previous damage

The existence of a mandatory scheme does not mean that any damage from any tank is covered.

Old tanks that are no longer in use

Contamination from an old tank whose use ended long ago is, as a rule, not covered by the insurance scheme for active domestic oil tanks.^[3]

If contamination is found, the property may be mapped. Public investigation or clean-up is prioritised according to the risk to groundwater and human health, among other things. This does not necessarily mean that the public authorities will remove all contamination straight away.

It is therefore important to distinguish between:

• A legal active tank covered by the insurance scheme
• A tank that has just been taken out of use
• An old, correctly decommissioned tank
• An old tank that has not been decommissioned
• Documented oil contamination

What do V1 and V2 mean?

The Danish regions map soil contamination at two levels of knowledge.

The Capital Region of Denmark (Region Hovedstaden) describes V1 as suspicion based on previous activities and V2 as documented contamination.^[4]

A former oil tank can form part of a V1 assessment, but a registered tank does not automatically trigger V1 mapping.

The soil contamination certificate

A soil contamination certificate brings together the registered status of the property.

It can show:

• V1 or V2 mapping
• Partial mapping
• Qualified status for residential land (nuancering på boliggrund)
• Information on area classification (områdeklassificering)
• Relevant case details or references

The certificate tells you what the authorities have registered. It is not necessarily the result of new soil samples across the whole plot.

If the home is in a region other than the Capital Region, the relevant region's service must be used. The municipality handles area classification and rules on soil removal, among other things, while the region is responsible for mapping under the Danish Soil Contamination Act (jordforureningsloven).

Signs and discrepancies

The following can prompt further questions:

• The house previously had an oil-fired boiler, but there is no tank information
• BBR and the seller's information differ
• A tank is registered as in use even though the house has another heating supply
• A tank is registered as decommissioned, but the method of decommissioning is unclear
• There are old filler pipes or vents
• The tank's year of manufacture is unknown
• The documents show different locations
• There is an oil smell, discolouration or affected soil
• The property is V1 or V2 mapped
• The municipality has an environmental case that is not clearly stated in the sales material

A single sign does not prove that the soil is contaminated. It shows which question has not yet been answered.

Possible investigations

The investigation should fit the specific question.

A soil sample taken in one spot cannot necessarily describe the whole plot. Location, depth, tank type and possible routes of spread all matter for how the investigation is designed.

So an environmental site investigation should be planned by a specialist who has the relevant information about the tank and the property.

Liability and the purchase agreement

It is too simple to say that the buyer is automatically personally liable for all previous contamination.

Several sets of rules can be relevant:

• The duty to decommission an unused tank
• The authorities' power to issue orders
• The insurance scheme for domestic oil tanks
• The region's public action
• The seller's information
• The terms and conditions of the purchase agreement
• Possible claims between buyer and seller

If a tank matter needs to be clarified after signing, the purchase agreement should clearly set out the deadline, the investigation and the consequence.

A general adviser condition (rådgiverforbehold) and a specific environmental or tank condition can differ in scope. Also read the guide on lawyer and bank conditions.

Impact on financing and value

An unresolved oil tank or registered soil contamination can affect the assessment made by the bank and the mortgage credit institution (realkreditinstitut).

This can concern, among other things:

• Uncertainty about future costs
• How easily the property can be sold
• The use of the house and garden
• The possibility of building work or soil removal
• Insurance matters
• The valuation of the property

This is not the same as a general ban on lending. The outcome depends on the status of the contamination, documentation, location, risk and the specific lender's assessment.

Four practical scenarios

1. Active and legal tank

BBR, the tank certificate and the physical tank match. The age limit has not been exceeded, and oil is supplied through a scheme with liability insurance.

The key questions remain the tank's installation, pipework, future decommissioning and the specific insurance cover.

2. Decommissioned and removed tank with documentation

There is an invoice, photos and municipal registration. The documents show that the tank has been removed.

This is stronger documentation than a single line in BBR. It still only tells you something about the condition of the soil if an environmental investigation was also carried out and documented.

3. Decommissioned tank still in the ground

BBR shows a sealed-off tank, and the municipality has received notification. This can be a legal method of decommissioning.

The buyer may still need to know the location, because the tank can matter for later building work, gardening or excavation.

4. Former oil-fired boiler, but no coherent documentation

The seller says the tank was removed many years ago. BBR shows no tank, and there is no invoice or photos.

This is not proof of contamination. It is a gap in the documentation, where the municipality, building case files, old drawings and any physical or environmental site investigation can provide more information.

Checklist when buying a home

Registration

• What does BBR say about the tank?
• Does the operating status match the home's current heating supply?
• Are the year of manufacture, material and location known?
• Are there several current or former tanks?

Documentation

• Is there a tank certificate?
• Is there a notification of installation?
• Is there a notification of decommissioning?
• Is there an invoice and a description of the work?
• Are there photos or documentation of disposal?
• Has the municipality been asked about tank and environmental cases?

Soil contamination

• What does the soil contamination certificate show?
• Is the plot V1 or V2 mapped?
• Is only part of the registered plot mapped?
• Is the area covered by area classification?
• Are there previous soil samples or environmental reports?

Sale and financing

• Is the tank matter described in the purchase agreement?
• Are any deadlines and conditions clear?
• Has the bank been given the relevant information?
• Has the insurance cover been checked for the specific tank?
• Have possible costs been included in the purchase budget?

Common misconceptions

BBR shows decommissioned, so the soil is clean

No. Decommissioning is about taking the tank out of use. It is not automatically a soil investigation.

A decommissioned tank must always be dug up

No. The rules allow the tank to be emptied, sealed off and left in place.

BBR is a physical approval

No. BBR is a register. The information can be based on owners' own reports and cases handled by the authorities.

No V2 mapping means clean soil

No. It means the region has not mapped the property as having documented contamination. The whole plot has not necessarily been investigated.

V1 means the soil is contaminated

No. V1 means suspicion based on previous activities.

The insurance covers all oil tanks

No. Cover depends on, among other things, whether the tank and pipework meet the rules and whether the tank is still covered by the scheme.

A new owner is automatically liable for all historical contamination

No. The current owner has a duty to deal with a tank that has not been decommissioned, but liability for a specific historical contamination depends on several factors.

A single soil sample gives the whole answer

Not necessarily. Where the sample is taken and how the investigation is designed both matter.

In short

An oil tank must be assessed on more than a single line in BBR.

Look at the registration, the documents and the actual conditions together. Distinguish between the tank's technical status, the soil's contamination status, the insurance cover and liability under the purchase agreement.

A decommissioned tank can lie legally in the ground. V1 is not the same as documented contamination. And the absence of mapping is not the same as a full investigation of the soil.

If a possible tank matter could lead to costs, you can include them in the Purchase Budget calculator.

Also read the guides on documentation when buying a home and building surveyors.

BoligKlar gives you a second pair of eyes and an overview. The specific environmental and legal assessment must be made on the basis of the property, the documentation and the purchase agreement.

Frequently asked questions