The decommissioned oil tank in the garden
In older houses you can come across an emptied and decommissioned oil tank, an old, buried tank that's been sealed off but not removed. Even an empty tank can corrode over time, and in some cases the rules can require actual removal, not just decommissioning.
How to check: the tank is typically listed in the property data report (ejendomsdatarapport). Ask for documentation of the decommissioning date, and ask the municipality whether physical removal is required.
What it costs: simple decommissioning (the tank is sealed and filled, but stays in the ground) typically costs 2,500-8,000 kr. Full physical removal (excavation) typically costs 15,000-30,000 kr, depending on the tank's size, location, and whether soil samples are required.
Easements and the land register: what does the deed actually say?
On plots from the first half of the 1900s you can find a registered easement (servitut) with the text "contains financial obligations, see deed". Easements are burdens or rights registered against the property, they follow the land, not the owner, so they also apply to you as the new owner. This can mean payment obligations for a road, utilities or sewer, building lines, a right of first refusal, or an obligation to accept a neighbour's cables, and the text usually just points to a deed almost no one actually reads.
How to check: request the full deed document (a land register extract), not just the line in the sales brochure (salgsopstilling). Don't treat it as a formality until you've read it. Easements can be viewed for free on tinglysning.dk, but the full deed text often has to be requested by your agent or lawyer.
Private water supply, not the municipal mains
In the countryside some homes have a "private water supply system", water from your own borehole or well, not the municipal waterworks. That means you're responsible for the pump, periodic water-quality testing and potential future repair or new-borehole costs.
How to check: ask about the system's age, the pump's condition, and when the water quality was last tested.
Upcoming separate sewer requirements, and who pays
Many older houses share one drain for rainwater and wastewater. Municipalities increasingly require separate sewer systems (separatkloakering), splitting the two, and when the requirement lands, the bill lands on the property owner, not the municipality. The sales brochure (salgsopstilling) sometimes mentions it, with the agent taking no responsibility for it.
How to check: ask the municipality whether there's a timeline for separate sewer requirements on that specific road, it's publicly available information.
What it costs: a LAR solution, where rainwater is drained on your own plot via a soakaway (faskine), typically costs 10,000-20,000 kr. Connecting rainwater to the mains typically costs 30,000-105,000 kr. The overall national range is 10,000-125,000 kr, depending on the solution, plot size, soil conditions and machine access. Ordering jointly with neighbours, e.g. through the homeowners' association, brings the price down noticeably.
Private shared road: you maintain the road yourself
This is a cost category foreign buyers often don't know exists at all, because in many countries the road outside the house is automatically municipal. If your address sits on a private shared road (privat fællesvej), maintenance of the road falls on the adjoining property owners, not the municipality.
In practice that means a duty to maintain the roadway, pavement, cycle path and verge in front of your property, usually up to the middle of the road, plus snow clearing and sweeping in winter. If the road needs a full renovation, the cost is split between the property owners, typically by usage, that can be a few thousand kroner, or it can be several tens of thousands if the whole surface needs replacing.
How to check: the road's status appears in the property data report. Ask whether a homeowners' association exists, whether it has a road fund, and whether renovation has already been decided.
Soil contamination: V1 and V2 aren't the same thing
Soil contamination is usually mentioned in one line in the listing, and that line doesn't explain much. The grading is clear.
V1, knowledge level 1: there's information that activity took place on the plot that may have contaminated the soil. It's a suspicion, not a fact. V2, knowledge level 2: the contamination is documented.
But V2 itself isn't uniform either, the risk is split into three categories: F0, contamination with no risk for residential use, F1, no risk if simple precautions are followed (e.g. not growing vegetables in open soil), and F2, a real health risk from living on the plot. "Mapped at knowledge level 2" can therefore mean almost nothing or a serious problem, the difference is one digit, which the listing doesn't mention.
How to check: the property data report shows the mapping status. The region holds the detailed material with the nuance, ask for it before you bid, not after.
"Newly renovated", but not in BBR
A home is marketed as fully renovated, but the official BBR building register shows "year of significant renovation: not stated". Updating BBR after a renovation is the owner's responsibility and sometimes gets postponed. It's not a problem in itself, but it can affect future registration and certain tax matters, and a "fully renovated" impression can in practice turn out to be partial.
How to check: compare the listing's stated renovation year with the BBR registration, and ask whether a BBR update has been submitted.
What does change-of-ownership insurance (ejerskifteforsikring) cover, and what doesn't it cover?
Ejerskifteforsikring (insurance against hidden defects, paid half by the seller) is one of the most misunderstood parts of a Danish home purchase. The seller is required to present an offer for it, and if the seller pays half the premium and you accept, you get 10 years of legal protection instead of the usual 5. But the policy is far from all-covering.
What it typically covers: hidden damage and building defects on what's included in the condition report and the electrical report, conditions that existed on the handover date but couldn't be discovered in an ordinary, non-destructive inspection.
What it typically doesn't cover: conditions already noted in the condition report or electrical report (they aren't "hidden" by definition), normal wear and ongoing maintenance, cosmetic issues, structures and land outside the home's building envelope such as a pool, terrace, fence or shed unless explicitly included, and by default soil contamination and mould unless you've purchased extended cover. The excess, typically a few thousand kroner per claim, is always yours to pay.
How to check: read the insurance offer's terms and exclusions, not just the premium. Compare them against the condition report's K-values (K0-K3), since those conditions are exactly what the policy is built around.
Bidding-round rules: what can the seller and agent actually do?
Since Denmark's home purchase act (boligkøbsloven) came into force, the rules on bidding rounds have tightened. If the seller intends to run a bidding round, negotiating with several interested buyers at once, rather than accepting offers in the order they arrive, it must be stated clearly in the sales brochure (salgsopstilling) before you place a bid. If it isn't stated, and you bid the asking price, an agreement can in certain cases be treated as concluded immediately, without an actual round.
As a buyer you always have a fixed 6-working-day right of withdrawal after a signed purchase agreement, for a fee of 1% of the purchase price to the seller, and that period doesn't extend, whether or not the condition report, electrical report and insurance offer were available when the agreement was signed. What changes if those reports are missing is the seller's position: without them, no change-of-ownership insurance can be issued, so the seller loses the liability protection against hidden defects that the insurance would otherwise provide. Using an independent adviser, such as a bank adviser, isn't a legal requirement, but it's commonly written into the purchase agreement as a voluntary adviser-reservation clause (rådgiverforbehold), and it's a recommended, if optional, safeguard.
How to check: read the section on bidding rounds in the sales brochure (salgsopstilling) before you bid, not after. Ask the agent directly whether there are other offers, and whether the property is sold by negotiation or on a first-come basis.
Comparison: where do you find each cost in the documents?
None of the items below is secret. They sit in publicly available documents; the hard part is knowing which document shows what.
| Type of cost | Typical range | Where to find it |
|---|---|---|
| Oil tank, decommissioning/removal | 2,500-30,000 kr | Property data report |
| Easement with financial obligations | Varies, no fixed price | Tinglysning.dk + full land register extract |
| Private water supply, upkeep/new borehole | Varies, ongoing running cost | Property data report + seller disclosures |
| Separate sewer requirement | 10,000-125,000 kr | Municipal wastewater plan + property data report |
| Private shared road, upkeep/renovation | A few thousand to several tens of thousands of kr | Property data report + homeowners' association bylaws |
| Soil contamination V2/F2, remediation | Varies widely by scope | Regional contamination map + property data report |
| Missing BBR update | Varies, can affect tax/resale | BBR notice |
| Change-of-ownership insurance, excess/exclusions | Varies by policy | Insurance offer + condition report's K-values |
| Registration fee, deed + any mortgage deed | 0.6% of price + 1,850 kr; mortgage deed 1,825 kr + 1.25% of loan amount (2026) | Deed and settlement statement from your lawyer/agent |
The figures here are general and for orientation, not a calculation of your specific finances. Rates, deductions and rules change, and your own case may differ from the example. Use these numbers as a starting point for a question to your bank, accountant or adviser, not as a final answer.
Check which hidden costs might apply to this house
Tick the items that are mentioned in the listing, the property data report or the land register extract for the house you're looking at. I add up the known ranges from the article above into a combined interval.
This is not a valuation of your specific property, only an overview of known cost categories from this article. The actual amounts depend on the house, the municipality and the specific documents, and should always be checked in the property data report, the land register extract and the BBR notice.
How to check all of it in one evening
- Property data report. Oil tank, road status, water supply, soil contamination mapping. Four of the items above sit here.
- Land register extract, full text. Easements and wording about financial obligations.
- BBR notice. Renovation year, square metres, number of buildings. Compare against the listing photos.
- The municipality's website. Timeline for separate sewer requirements on your specific road, road plans.
- The homeowners' association, if there is one. Bylaws, road fund, work already decided.
- The insurance offer. Exclusions and excess, checked against the condition report's K-values.
Altogether that's about two hours per property if you know where to look. If you don't, it's a few evenings, and still with a risk of missing something.
What does it cost if any of this needs fixing?
A new roof runs 400-2,500 kr per m² depending on roof type, for a 100 m² home that is 40,000-250,000 kr in total. New electrical wiring throughout a house runs from 25,000 to 180,000 kr. Excavating an oil tank runs 15,000-30,000 kr, a separate sewer requirement 10,000-125,000 kr. For comparison, paint and surface work costs a few thousand kroner. That's why cosmetics are rarely what should worry you most.
Source: prisberegner.dk, bygge.dk and byggeli.dk, July 2026. Typical market levels, not fixed prices. In the greater Copenhagen area, tradesperson rates typically run 15-25% higher than in Jutland.
The bottom line
Ask which of the house's future bills are already known and which have not arrived yet.
I look for the hidden costs before you bid
A BoligCheck reviews the property data report, easements, the land register extract and documents, and pulls together the future bills the listing doesn't highlight, in one overview.
Order a BoligCheck, 299 krFrequently asked questions
What does a decommissioned oil tank on the plot mean?
An old, emptied tank that has been sealed but not physically removed. Even an empty buried tank corrodes over time, and in some cases the rules require full decommissioning or removal. Ask for documentation of status and date, it's typically listed in the property data report.
What does it cost to remove an oil tank?
Simple decommissioning, where the tank is sealed and stays in the ground, typically costs 2,500-8,000 kr. Physical excavation typically costs 15,000-30,000 kr, depending on size, access and whether soil samples are needed.
What does an easement with financial obligations mean?
A registered burden on the plot, often from the first half of the 1900s, which can include payment obligations for a road, utilities or sewer. The text refers to a deed in the land register that should be read in full, rather than assumed to be a formality.
What does change-of-ownership insurance (ejerskifteforsikring) cover, and what doesn't it cover?
By default it covers hidden damage and defects on what's included in the condition report and electrical report, present on the handover date but not detectable in an ordinary inspection. It typically doesn't cover conditions already noted in the reports, normal wear, cosmetic issues, structures outside the home's envelope like pools and sheds, and usually not soil contamination or mould unless you've bought extended cover.
What are the bidding-round rules for buying a home in Denmark?
If the seller intends to run a bidding round with several buyers, it must be stated in the sales brochure (salgsopstilling) before you bid. Without that disclosure, accepting an offer at the asking price can in some cases become binding immediately. As a buyer you always have a fixed 6-working-day right of withdrawal for a fee of 1% of the purchase price, whether or not the condition report, electrical report and insurance offer were available when the agreement was signed. If those reports are missing, the seller instead loses the liability protection against hidden defects, since change-of-ownership insurance cannot be issued without them.
Who pays for separate sewer requirements?
If the municipality eventually requires rainwater and wastewater to be separated, the cost falls on the property owner. Everything from the house to the property line, including the connection and its ongoing maintenance, is your responsibility.
What is a private shared road, and who maintains it?
A road maintained by the adjoining property owners, not the municipality. The duty covers the roadway, pavement and verge in front of your property, usually up to the middle of the road, plus winter snow clearing.
What's the difference between V1 and V2 soil contamination?
V1 means there's a suspicion that activity on the plot may have contaminated the soil. V2 means documented contamination. V2 is further split into F0, F1 and F2 by risk level for habitation, only F2 is a real health risk.
Why doesn't a renovation always show up in the BBR register?
Updating the BBR register after a renovation is the owner's responsibility and sometimes gets postponed. So a home can be marketed as fully renovated without it appearing in the official register. Ask whether an update has been filed.
Where do I find all this information before I bid?
The property data report, the full land register extract, the BBR notice and the municipality's website. All of it is publicly available, but you need to know which lines to read.
Yurii Khlivnenko, founder of NordIndsigt
Background in construction: roofs, facades and ventilation. I review every report personally before it goes out.
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