Renovating a bathroom in a rented flat is more than a building task. If the tenants still live in the flat, they are without a bathroom while the work is under way, and once it is finished the question arises whether the rent may go up. This article summarises what the Swiss Code of Obligations (OR) and the tenancy ordinance VMWG (Verordnung über die Miete und Pacht von Wohn- und Geschäftsräumen) say about it — for landlords, property managers and tenants.
The basis: the landlord maintains the flat
Under Art. 256 OR, the landlord is required to make the property available ‘in a condition fit for its designated use and to maintain it in that condition’. For their part, under Art. 259 OR tenants remedy defects that can be dealt with by minor cleaning or repairs as part of regular maintenance. When repairs in the bathroom keep piling up, a complete renovation is often the more economical answer than the next patch-up.
Renovating an occupied flat
Renovations and modifications by the landlord are governed by Art. 260 OR. The landlord may carry them out ‘only where conscionable for the tenant or lessee and the lease has not been terminated’. In doing the work, the landlord ‘must give due consideration to the tenant or lessee’s interests’; claims for a rent reduction and for damages are expressly reserved.
The law does not put a figure on what is reasonable. In practice, giving due consideration mainly means informing the tenants early, providing a reliable schedule and keeping the time without a bathroom as short as possible. During a complete renovation the bathroom cannot be used from removal to installation; on our reference project it took three to four weeks from strip-out to acceptance. If the flat has only one bathroom, the question of how the tenants will manage during those weeks belongs at the start of the planning.
Rent reduction during the work
A bathroom that cannot be used for weeks restricts the use of the flat. Where the property is rendered unfit or less fit for its designated use, under Art. 259d OR the tenant may require the landlord ‘to reduce the rent proportionately from the time when the landlord or lessor became aware of the defect until the defect is remedied’. The law gives no fixed percentage; it speaks of a ‘proportionate’ reduction. A short, well-coordinated construction period therefore also makes economic sense.
Renovating at change of tenant
Because Art. 260 OR only allows renovations as long as the lease has not been terminated, the renovation of a flat under notice falls into the period after the tenants move out. But even otherwise, a change of tenant is often the quietest moment in practice: in a vacant flat nobody’s use is restricted, and arrangements are mainly needed with the neighbours in the building. You keep the vacancy short if the site visit takes place before move-out, with the outgoing tenants’ consent. More on this in the article Renovating a vacant flat at change of tenant.
Rent increase after the renovation
Under Art. 269a let. b OR, rents are not generally held to be unfair if ‘they are justified by increases in costs or by additional services provided by the landlord’. What counts as an additional service (Mehrleistung) is set out in Art. 14 VMWG: ‘investments in value-enhancing improvements, the enlargement of the leased property and additional ancillary services’. Paragraph 1 adds, on comprehensive overhauls (umfassende Überholungen): ‘As a rule, the costs of comprehensive overhauls are deemed to be value-enhancing investments to the extent of 50–70 per cent.’
The key is the line between this and maintenance. Under Art. 14 para. 3 VMWG, ‘only the part of the costs that exceeds the cost of restoring or maintaining the original condition’ may be claimed as an additional service. Art. 14 VMWG also states:
- Rent increases due to value-enhancing investments are not unfair if they ‘do not exceed the appropriate rate for interest, amortisation and maintenance of the investment’ (para. 4).
- They may only be notified ‘once the work has been completed and the relevant supporting documents are available’ (para. 5).
Under Art. 269d OR, the increase must be notified at least ten days before the beginning of the notice period, with reasons and using a form approved by the canton. If the form or the reasons are missing, the increase is void. Whether a project counts as a comprehensive overhaul, and what share is value-enhancing in the individual case, is best clarified by the landlord with their legal adviser before work starts.
How an itemised quote helps
The line between maintenance and additional service depends on the paperwork. You receive our fixed-price quote within 48 h of the site visit, item by item, with labour and materials shown separately. This makes it possible to see which work restores the previous condition and which goes beyond it; the allocation itself is made by the property management. At a change of tenant we can also structure the quote and invoice so that items chargeable to the outgoing tenants are shown separately.
As a guide price for a complete bathroom renovation, we calculate CHF 8'500 to 19'000 for the labour; materials and sanitary fixtures are charged separately. What determines where you land in that range is explained in the article How much does a bathroom renovation cost in Zurich in 2026? We give a 5-year warranty on our work from acceptance.
When the tenants want to renovate the bathroom
If the tenants want to modernise the bathroom at their own expense, Art. 260a OR applies: the tenant may renovate or modify the property ‘only with the written consent of the landlord or lessor’. Once consent has been given, the landlord may require the previous condition to be restored only if this has been agreed in writing. If, at the end of the lease, the flat has appreciated significantly in value as a result of the change the landlord consented to, the tenant may claim appropriate compensation. It is therefore worth both sides recording the scope, any reinstatement and the compensation in writing before work starts.
Checklist for property managers
- Check whether the lease has been terminated (Art. 260 OR)
- Inform the tenants early, with the schedule and the days without a bathroom
- Allow for a possible rent reduction during the work (Art. 259d OR)
- Quote item by item, so that maintenance and additional services can be separated
- Keep the supporting documents; notify any increase only after completion and on the form
For property managers with several properties there is a framework agreement with fixed terms for every property in the portfolio. More under For property managers and Bathroom renovation in Zurich.
This article is not a substitute for legal advice. It reflects the wording of the OR and the VMWG on fedlex.admin.ch in October 2026. Quotations from the OR follow the English translation published there, which is for information only and has no legal force; the VMWG is not available in English there, so quotations from it are our own translation. The German text of the law and your lease are what count.