If something in your flat stops working properly, such as the heating, the hot water or a wall covered in mould, German law reduces the rent by itself for as long as the problem lasts. This is Mietminderung. You don't need the landlord's agreement, but you do need to report the defect, and paying too little can put your tenancy at risk.
This guide covers flats rented as a home. It explains the rule, what usually counts as a defect, how to report it, the safer and riskier ways to pay less, and what else you can ask for when the landlord does not repair. Leases for business premises are not covered.
1. The rule: the rent goes down by law
The landlord has to hand over the flat in a condition fit for the agreed use and keep it that way for the whole tenancy (§ 535(1) BGB). If a defect reduces how well you can use the flat, you only owe an appropriately reduced rent for that time. If the flat can't be used at all, you owe no rent for that time (§ 536(1) BGB).
- It happens automatically. The reduction is not something the landlord grants. It applies from the time the defect affects the flat until it is fixed.
- Minor problems don't count. An insignificant reduction in usability is ignored (§ 536(1) sentence 3 BGB).
- A promised feature counts too. If the landlord expressly promised something about the flat and it is missing or later disappears, the same rule applies (§ 536(2) BGB).
- The lease can't take it away. For a flat, a clause that excludes or limits your right to a reduction to your disadvantage is invalid (§ 536(4) BGB).
- One exception: energy-saving work. If the problem comes from building work that saves energy in the building (an energetische Modernisierung, such as insulation), it is ignored for the first three months (§ 536(1a), § 555b No. 1 BGB).
2. What counts as a defect
A defect (Mangel) is a difference between the state the flat is actually in and the state the lease promises. Problems tenants commonly raise include:
- heating that fails or doesn't get rooms warm in the cold months;
- no hot water, or water that is unsafe to use;
- mould and damp, leaks and water damage;
- a broken lift, door entry system or window;
- heavy noise or dirt from building work in the building.
Problems from outside the building, such as a building site next door, are a frequent grey area.
Whether a particular problem is a defect, and whether it is more than insignificant, depends on the lease, the building and how much the problem affects daily life. Mould is the most disputed case: landlords often say it comes from how the flat is heated and aired, tenants that it comes from the building. Photos, dated notes and humidity readings help either way, and a disputed case can need an expert's report.
Defects you knew about when you signed don't count. If you knew of a defect when you signed the lease, you can't reduce the rent for it. The same applies if you didn't know because of gross negligence, unless the landlord concealed it on purpose. If you take over the flat knowing of a defect, you keep your rights only if you reserve them at the handover, for example in the handover record (§ 536b BGB).
3. Report it first, in writing
You must tell the landlord about a defect without undue delay (§ 536c(1) BGB). If you don't, you can't reduce the rent for the time the landlord couldn't fix the problem because they didn't know about it, and you may have to pay for damage that gets worse in the meantime (§ 536c(2) BGB).
- Write it down. A letter or email you can prove you sent is far better than a phone call. Write to the landlord or the management company named in the lease.
- Describe the problem, not the law. Say what is wrong, where, since when and how it affects you. Attach photos.
- Ask for a repair by a date. A clear date matters later if the landlord does nothing (see section 6).
- Let them in. Offer dates for a viewing and for the repair.
- Keep a record of the defect over time: dates, temperatures, photos, messages.
4. How much less?
The law only says the rent is reduced "appropriately". There is no official table. The amount depends on how much of the flat is affected, how badly and for how long. The percentage tables found online (Mietminderungstabellen) collect past court decisions about other flats. They show a range, not what you can deduct.
The reduction ends when the defect is fixed. A defect that only matters part of the year, such as heating that fails in summer, counts for less than the same defect in January. How much a particular defect is worth is exactly the question a housing lawyer can answer for your flat.
5. Pay less, or pay in full "under reservation"
This is where tenants get into trouble. If you deduct more than a court later finds appropriate, the difference counts as unpaid rent. Arrears above set thresholds allow the landlord to terminate without notice (§ 543(2) No. 3 BGB, § 569(3) BGB; the rent arrears guide explains them).
There are two common ways to handle it:
- Pay less. You pay the reduced rent straight away and tell the landlord in writing that you are reducing it because of the reported defect. This puts the risk of a wrong amount on you.
- Pay in full "unter Vorbehalt". You keep paying the full rent and state in writing that you pay under reservation because of the defect. You then claim back the overpayment once the amount is clear. The reservation matters: money paid while knowing it wasn't owed generally can't be reclaimed (§ 814 BGB). This route keeps your tenancy safe while the amount is unclear.
A claim for overpaid rent can be set off against future rent even if the lease says otherwise, but you must announce it in writing (text form, such as an email) at least one month before that rent is due (§ 556b(2) BGB). Claims for overpaid rent generally expire after three years, counted from the end of the year in which they arose and you knew the facts (§§ 195, 199 BGB).
Some tenants also hold back part of the rent on top of the reduction to push for the repair. That is a separate right with its own limits, and it raises the same arrears risk. Get advice before relying on it.
6. Getting it fixed, and leaving
- Repairing it yourself. You can fix the defect and claim the necessary costs from the landlord if the landlord is in default with the repair, or if an immediate repair is needed to preserve the flat, such as stopping a leak (§ 536a(2) BGB). Default usually means the landlord was asked and didn't repair in time. Keep the invoices.
- Damages. If the defect was there when you signed, was caused by something the landlord is responsible for, or the landlord is in default with the repair, you can also claim damages, for example for ruined belongings (§ 536a(1) BGB).
- Leaving. If the landlord does not give you use of the flat, you can terminate without notice, usually only after a reasonable deadline to fix the problem has passed (§ 543(2) No. 1, (3) BGB). If living there seriously endangers your health, that is also an important reason (§ 569(1) BGB). Terminating without notice is risky: if the termination turns out to be invalid, the rent keeps running. The guide to ending a lease covers the ordinary route.
- Court. Disputes about a residential lease go to the local court (Amtsgericht) for the flat's area, whatever the amount (§ 23 No. 2(a) GVG).
7. When a lawyer can help
Reporting a defect is something you can do yourself. A housing lawyer is worth asking before you deduct anything from the rent, when the landlord blames you for mould or damp, when the defect lasts for months, when you want to repair it yourself and send the bill, or when you are thinking of leaving because of it. A lawyer can tell you what reduction is realistic for your flat and how to claim it without risking the tenancy.
Have the lease, the handover record, your defect reports with dates and photos, the landlord's replies and your rent payments ready. You can request an English-speaking housing lawyer to review them.
Sources checked on 12 October 2026. The linked provisions are the German statutory text; the explanations here are general information.