Undersökningsplikt (the buyer's duty to investigate) when buying a house – what you must check yourself
Undersökningsplikten (the buyer's duty to investigate) means you as the buyer are responsible for examining the house before the purchase. Anything you could have discovered through a thorough inspection, you cannot complain about afterwards, even if you didn't actually see it. The duty follows from jordabalken (the Land Code) and is extended by warning signs in the house or in the inspection report.
How it works
Undersökningsplikten comes from the fourth chapter of jordabalken (the Land Code). The main rule is that the property is sold in befintligt skick (as-is condition) and the buyer cannot invoke defects they should have discovered through an inspection that is reasonable given the property's condition, age and other circumstances. A house from 1962 with its original drainage is thus expected to be examined more thoroughly than a newly built villa.
The duty is flexible, not a fixed checklist. It expands as soon as there's a warning sign: damp stains, an odour, a crawl space (krypgrund), a risk construction (riskkonstruktion) known for that building year, or a note in the inspection report saying something should be investigated further. Then simply looking isn't enough — you're expected to go further and investigate the cause, in practice through an in-depth investigation with moisture measurement or sampling.
The duty to investigate covers what is accessible without damaging the property: crawl spaces, attics, wet rooms, roofs viewed from the ground or a ladder, windows, and electrical and plumbing installations to the extent they're visible. You're also expected to read the documents — drawings, building permits, utility connection agreements, previous inspection reports and the energy declaration.
The opposite of the buyer's duty to investigate is the seller's duty to disclose (upplysningsplikt), which under Swedish law is weaker: the seller has no general obligation to disclose everything, but may not give false information or actively conceal defects. Defects you could neither discover nor should have suspected are dolda fel (hidden defects), for which the seller is liable for ten years.
In terms of timing, you carry out the investigation before the purchase — in practice at the viewing, through your own inspection before bidding, or within the inspection clause's (besiktningsklausul) time limit after signing the contract.
Step by step
- 1Find out the house's age and method of constructionBuild year and construction determine which risk constructions are typical, and therefore how far your duty extends.
- 2Order your own inspectionHire an independent inspector (besiktningsman) that you pay for yourself. A pre-purchase inspection (överlåtelsebesiktning) doesn't fulfil the duty on your behalf, but it documents what was examined.
- 3Go through the accessible spacesCrawl space, attic, wet rooms, basement and roof. Odours, stains and discolouration are signals that extend the duty.
- 4Read the documents about the houseBuilding permits, drawings, energy declaration, previous inspection reports and receipts for work done. Missing documentation on a wet room is a warning sign.
- 5Follow up on every warning signWhen the report mentions fortsatt teknisk utredning (further technical investigation) or förhöjd fuktkvot (elevated moisture level), the duty isn't fulfilled until the cause has been investigated.
- 6Document what you've examinedKeep reports, measurements, photos and emails. In a future dispute, it's your documentation that shows what was discoverable.
Common mistakes
Assuming the inspector takes over the duty
A pre-purchase inspection is visual, and the inspector normally disclaims anything not visible. The duty to investigate stays with you — the inspection is a tool, not a transfer of responsibility.
Stopping at a warning sign
The most common and costly mistake: the report says something should be investigated further, the buyer reads it as a formality and proceeds to completion. The warning then counts as discovered, and the chance to call it a hidden defect is gone.
Trusting the seller's word
The seller saying the damp stain is old and fixed doesn't help if it's not in writing and turns out to be wrong. Verbal statements are hard to prove and rarely remove your duty to investigate.
Signing a disclaimer clause without factoring it in
A friskrivningsklausul (disclaimer clause) can shift even hidden defects onto you. The duty to investigate then becomes, in practice, your only protection, and needs to be carried out far more thoroughly.
How this shows up in the inspection report
The inspection report is essentially the map of where your duty to investigate expands. Every time the report mentions a risk construction, an elevated moisture reading, or recommends further investigation, you've received a warning sign you're expected to follow up on.
That's also where the costs are decided: a remark about a crawl space could mean a couple of thousand kronor in improved ventilation, or a drainage job running into six figures.
Terms in the report
What the repairs cost
Frequently asked questions
Does the duty to investigate apply even to what the inspector missed?
Yes. Hiring an inspector doesn't shift the duty. If the inspector missed something that was discoverable, that's primarily a matter between you and the inspection firm, not the seller.
Do I have to open up constructions to fulfil the duty?
Normally no — the duty covers what's accessible without intervention. But if there's a clear warning sign, you're expected to go further, and an in-depth investigation with a bore hole may then be required, with the seller's permission.
How long can I complain about a defect after the purchase?
The limitation period for defects in a property is ten years from possession (tillträde), but you must notify the seller (reklamera) within a reasonable time from when you discovered the defect. Don't wait — notify in writing as soon as you spot something.
Does an inspection ordered by the seller fulfil my duty?
It helps, but it was ordered by someone else, and the inspector's liability runs to whoever ordered it. Read it carefully and consider supplementing it with your own review of any points left open.
Got the inspection report? Upload it and within a minute you'll see what's serious and what it costs — the evidence for your negotiation.
Analyse my reportThis is general information, not legal advice. In a dispute or if you are unsure, contact a lawyer specialising in Swedish property law.