Short answer
Does a solar system require approval?
Guidance for owners across Switzerland who want to know before PV planning whether their project needs a building permit or goes through the notification procedure – with the federal basic rule, the limits and a pointer to where cantonal law takes over.
Important
This overview reflects the federal basic rule (legal status 1 January 2026, checked on 3 September 2026) and does not replace legal advice in individual cases. Whether your specific project must be notified or permitted is decided by the responsible authority of your municipality based on zone, protection status and design; deadlines and documents differ by canton. Clarify the procedure before the quote – replanning later because of an overlooked protection status is the most expensive route.
At a glance
Key figures: Does a solar system need a permit?
| Metric | Value |
|---|---|
| Basic rule | adapted systems in building and agricultural zones: notification only, no building permit (Art. 18a RPG) |
| Pitched roof | at most 20 cm above the roof surface, compact and low-reflectivity |
| Flat roof | at most 1 metre above the roof edge, not visible from below at 45 degrees |
| Facades | permit-free since 1 January 2026 if sufficiently adapted (Art. 32aᵇⁱˢ RPV) |
| Always requiring a permit | cultural and natural monuments of cantonal or national significance |
| Deadline and documents | governed by cantonal law – e.g. Zurich 30 days before construction |
Decision points
What determines the right path.
The basic rule is federal law: in building and agricultural zones, sufficiently adapted solar systems on roofs or facades need no building permit; such projects merely have to be notified to the responsible authority (Art. 18a para. 1 RPG, version in force since 1 January 2026). The use of solar energy generally takes precedence over aesthetic concerns.
On a pitched roof, a system counts as sufficiently adapted if it projects no more than 20 cm at right angles above the roof surface, does not protrude beyond the roof surface seen from above, is executed with low reflectivity according to the state of the art and is arranged compactly – technically required gaps or an offset layout due to the available area are permitted (Art. 32a para. 1 RPV).
Flat roofs have their own limits: at most 1 metre above the upper edge of the roof border, set back far enough that the system is not visible from below at a 45-degree angle, and executed with low reflectivity (Art. 32a para. 1bis RPV). Exceeding these values moves the project from the notification procedure into the ordinary permit requirement.
New since 1 January 2026, facade systems are also permit-free if sufficiently adapted. Art. 32aᵇⁱˢ RPV lists alternative conditions for this – such as a contiguous compact rectangular surface, the uniform replacement of previously uniformly designed facade elements, complete coverage of gable surfaces or a location in a work zone. In addition, unless cantonal law provides otherwise, the modules must not cover structuring or ornamental elements, must not protrude beyond the facade edges and must be mounted parallel to the facade at a distance of at most 20 cm and with low reflectivity.
The exceptions are named exhaustively: solar systems on cultural and natural monuments of cantonal or national significance always need a building permit and must not significantly impair such monuments (Art. 18a para. 3 RPG). In addition, cantonal law may impose a permit requirement in clearly defined protection zones – such as core zones or townscape protection areas – but may conversely also exempt further, aesthetically insensitive building zones from the permit requirement entirely (Art. 18a para. 2 RPG).
The notification procedure itself is cantonal: permit-free projects must be notified before construction starts to the building permit authority or another authority designated by cantonal law; the deadline, plans and documents are set by cantonal law (Art. 32a para. 3 RPV). In practice this means: Zurich requires notification 30 days before construction via eBaugesucheZH, Lucerne exempts systems up to 20 m² from notification, and St. Gallen routes the notification through the municipality. The details for your canton are in the linked permit guides.
Sequence
How the project stays cleanly managed.
- 1
Clarify the zoneif the building is in a building or agricultural zone, the federal basic rule of Art. 18a RPG applies. Outside these zones, the ordinary permit requirement under Art. 22 RPG applies.
- 2
Check protection statusclarify early whether the building is a monument, lies in a core or townscape protection zone or is listed in an inventory – this decides between notification and permit application and significantly affects planning and timeline.
- 3
Check the adaptation criteriameasure the project against the limits of Art. 32a RPV (pitched roof: 20 cm, compact, low reflectivity; flat roof: 1 metre and the 45-degree rule) or Art. 32aᵇⁱˢ RPV for facades. A project within the limits stays in the notification procedure.
- 4
Submit the notificationbefore construction starts, to the authority designated by your canton, usually the municipality. Deadline and enclosures are regulated cantonally – check your canton’s permit guide and submit the notification early enough for the cantonal deadline to expire before the planned start of construction.
- 5
Replan if a permit is requiredif a protected object or exceeding the limits triggers the permit requirement, the ordinary building application with its additional documents and longer procedure belongs in the project planning – ideally before the quote, not shortly before installation.
Checklist
Questions to settle before the quote.
- The basic rule under Art. 18a RPG: notify instead of permit
- When a roof system counts as "sufficiently adapted" (Art. 32a RPV)
- New since 2026: permit-free facade systems under Art. 32aᵇⁱˢ RPV
- Exceptions: monuments, protection zones and systems beyond the limits
FAQ
More questions: Does a solar system need a permit?
Sources
Official sources & references.
The responsible authorities are decisive. Always verify binding details – amounts, deadlines and conditions – for your specific property against the current status of the respective authority.