Forest distance in Switzerland: metres, exceptions and the procedure

The forest setback is the strictest building limit in Swiss building law and the most frequently underestimated one. Under Art. 17 para. 2 of the Forest Act, federal law requires only an appropriate minimum distance; the actual figure is set by the cantons. It ranges from 10 metres inside the Schaffhausen building zone to 30 metres outside the Zurich building zone. One point that many guides get wrong matters here: inside the building zone area in the canton of Zurich, a blanket distance of 30 metres does not apply. What applies is the forest setback line entered in the zoning plan, and that line can also lie closer to the forest.

This article shows how large the forest distance in Switzerland is in your canton, where it is measured from, what is expressly excluded from the forest setback, when falling below the minimum is realistic and what the setback costs in usable building land. All figures with a source reference, as at August 2026.

Table of contents

1. What the forest setback is and why it is so strict

2. How large the forest setback is: the federal government sets the framework, the canton sets the figure

3. Canton of Zurich: the decisive difference between building zone and non-building zone

4. Forest distance in Switzerland: the cantons compared

5. What does not fall under the forest setback

6. Where it is measured from and what a forest determination is

7. How to check in a quarter of an hour whether your plot is affected

8. When falling below the minimum is possible: the two permits

9. Which special circumstances count and which do not

10. Worked example: what the forest setback costs in building land

11. Five mistakes that become expensive at the forest edge

12. Frequently asked questions about the forest setback

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1. What the forest setback is and why it is so strict

The forest setback is the minimum distance that buildings and structures must keep from the forest edge. It does not serve a single purpose but four at once: protecting the forest from being impaired by the adjoining use, protecting buildings from windthrow and falling branches, keeping the forest edge accessible for maintenance and management with machinery, and preserving the ecological function of the forest edge as a transition zone.

For the client it is above all one thing: a hard boundary that can considerably reduce the usable building land, even if the plot lies entirely within the building zone and the building and zoning regulations allow a good utilisation. Unlike the boundary setback towards neighbours, the forest setback cannot be defused by an agreement with the neighbours, because the forest has nobody to negotiate with. That is exactly what makes it the most awkward of all building limits.

2. How large the forest setback is: the federal government sets the framework, the canton sets the figure

The federal Forest Act itself does not name a figure in metres. It obliges the cantons to prescribe an appropriate distance:

Art. 17 para. 2 WaG (SR 921.0): The cantons shall prescribe an appropriate minimum distance between buildings and structures and the forest edge. In doing so they shall take account of the location and the expected height of the stand.

Since 1 January 2017, Art. 17 has contained an additional third paragraph that expressly permits falling below the minimum: For important reasons, the competent authorities may permit the minimum distance to be undercut, subject to conditions and requirements. That is the federal basis on which every forestry law exemption rests.

The practical consequence: a figure from another canton is of no help to you. Between Zug with 12 metres and Zurich with 30 metres outside the building zone, the same plot geometry can quickly amount to a whole storey of living space.

3. Canton of Zurich: the decisive difference between building zone and non-building zone

In the canton of Zurich, the forest setback is set out in section 262 of the Planning and Building Act (PBG, LS 700.1). The wording is more precise than it is usually reproduced:

Section 262 para. 1 PBG: Buildings may not project beyond the forest setback line laid down in the zoning plan; outside the building zone area, the distance from the forest boundary under forestry law is 30 m.

Two entirely different regimes follow from this. Outside the building zone area, a rigid distance of 30 metres from the forest boundary under forestry law applies. Inside the building zone area, by contrast, it is not the distance that applies but the line. The only thing that matters is where the forest setback line is entered in the zoning plan of your municipality. A note on the source: the paragraph numbering of section 262 PBG given here corresponds to the version adapted under the Intercantonal Agreement on the Harmonisation of Construction Terminology. In municipalities whose building and zoning regulations have not yet been harmonised, the earlier version with different paragraph numbering applies. In substance this changes nothing.

These lines are laid down under section 66 PBG, and that is where the sentence that decides on building land can be found: the lines are to be laid down at a distance of 30 m from the forest boundary; in the case of small forest plots or particular local circumstances they may be drawn closer to or further away from the forest boundary.

So it is doubly worthwhile to look at the zoning plan rather than at a rule of thumb. With a small forest plot at the edge of a settlement, the line can lie considerably closer to the forest than 30 metres. Conversely, with a tall, exposed stand it can also be drawn further out. It is laid down by the municipality as part of land use planning and approved by the Building Directorate. Anyone who wants to change a line is changing a land use plan, and that is a planning procedure, not a building application.

4. Forest distance in Switzerland: the cantons compared

The following overview shows the standard values in our catchment area. What is decisive is always the current version of the cantonal act and the municipal zoning plan.

Canton	Forest setback for buildings	Particular features	Legal basis
Zurich	Forest setback line in the zoning plan, 30 m outside the building zone	Line can lie closer or further away (section 66 PBG)	Section 262 PBG, LS 700.1
Zug	12 m	10 m for underground structures and civil engineering works	Section 12 PBG, BGS 721.11
Aargau	18 m	8 m for small buildings, 4 m for roads	Section 48 BauG, SAR 713.100
Schwyz	15 m from the forest boundary	Access roads and forest roads permitted within the setback area	Section 67 PBG, SRSZ 400.100
Thurgau	25 m	15 m towards riparian woodland, differing distances possible in special land use plans	Section 75 PBG, RB 700
St. Gallen	as a rule 15 m	5 m for roads, measured from the stock boundary	Art. 91 PBG, sGS 731.1
Schaffhausen	10 m in the building zone, 30 m outside	Existing rights of buildings situated closer are preserved	Art. 20 cantonal forest act, SHR 921.100

The range from 10 to 30 metres is the reason why blanket statements such as "the forest setback is 30 metres" are of no use in advisory work. Always check the canton in which the site lies and then the zoning plan of the municipality.

5. What does not fall under the forest setback

The forest setback applies to buildings. Zurich law expressly exempts several building elements from it in section 262 PBG, and these exceptions are regularly overlooked in practice even though they give building volume back:

• Underground structures and parts of buildings: Section 262 para. 2 PBG exempts them, together with structures, from the forest setback. A basement, a covered parking level or an underground garage may therefore in principle extend further towards the forest than the building above it. Under forestry law the intervention still has to be assessed, in particular because of the root zones.

• Structures: Also covered by para. 2. The term building is narrower than the term buildings and structures, which becomes relevant for retaining walls, paths or parking spaces, for example.

• Open balconies without supports: Under section 262 para. 3 PBG they may project 2 metres into the setback area, regardless of their length. A balcony resting on supports or a loggia is not covered.

• Existing buildings within the setback area: They enjoy the protection of existing rights and may be maintained within their previous scope. For a replacement new build this is a considerably better starting position than for a new build on undeveloped land.

Ancillary buildings and extensions, by contrast, are buildings and are subject to the forest setback with no special rule. Anyone who wants to put the garden shed at the forest edge needs the same exemption for it as for the house.

6. Where it is measured from and what a forest determination is

Measurement is taken from the forest boundary under forestry law, not from what looks green on an aerial photograph. In Switzerland, forest is a legal concept, and it comes into being on its own: an unused area that grows over for years can legally become forest without anyone doing anything about it. Where exactly the boundary runs is therefore regularly unclear, and the uncertainty always falls on the client.

In the canton of Zurich, the responsible district forester of the Forest Division (Building Directorate, Office for Landscape and Nature) determines by formal ruling, on application by the landowner, whether an area is forest. That is the forest determination under Art. 10 WaG. Inside the building zone area and in cantonal land use zones, by contrast, static forest boundaries are laid down through the ordinary planning procedure with 60 days of public inspection, with an entry in the OEREB cadastre of public-law restrictions on landownership.

The practical advice: if you want to buy at the forest edge and the forest boundary has not been laid down in a legally binding way, clarify this before the purchase contract and not afterwards. A forest boundary that later runs differently shifts the entire setback area, and a project that just about worked then no longer works.

7. How to check in a quarter of an hour whether your plot is affected

You can take these four steps yourself before you involve anyone else:

1. Open the canton's GIS browser and display the layers forest, forest boundary and forest setback line. In the canton of Zurich this is the GIS browser at maps.zh.ch. Overlay the plot boundaries.

2. Query the OEREB cadastre. It records the legally binding public-law restrictions on landownership, including static forest boundaries. What is in the OEREB cadastre applies.

3. Check the municipality's zoning plan. The GIS browser shows the line, the zoning plan is the legally binding document. Check whether the forest setback line really is 30 metres or has been laid down differently.

4. Measure the remaining area. Subtract the setback area from the plot and look at what is left. If a sensible building volume no longer fits in, the answer has already been given.

If this check produces a tight picture, the next party at the table is the municipality and not the architect. What a full clarification before purchase looks like is shown in the article on property analysis before purchase.

8. When falling below the minimum is possible: the two permits

Falling below the minimum is the exception, not the rule, and it needs two permits, both of which must be in place. If one is missing, the project cannot be approved.

First, the planning law exemption permit from the municipality. In the canton of Zurich it is based on section 220 PBG. The wording is strict: relief from building regulations is to be granted in the individual case where special circumstances exist in which enforcing the regulations would appear disproportionate. And further: exemption permits may not run counter to the sense and purpose of the regulation from which they grant relief, nor may they otherwise infringe public interests.

Second, the cantonal assessment under forestry law. It is based on Art. 17 para. 3 WaG and does not ask about your building wishes but about the forest: do conservation, maintenance and use remain possible? Is the forest edge impaired as a habitat? Can work still be carried out in the event of storm damage? Responsibility lies with the cantonal forestry authority, that is, with the district forester.

The sequence decides on success. Anyone who submits the finished project and only then applies for the exemption is negotiating from the weakest possible position. Anyone who involves the forestry service before the design and develops the position of the building volume jointly often ends up with a solution that both sides can support. How the ordinary procedure runs after that is described in the article on the building application and the building permit.

9. Which special circumstances count and which do not

The concept of special circumstances is the pivot of every exemption. It means a situation that differs from the normal case, not a situation that is inconvenient for you.

• Usually counts: An unfavourable plot geometry or a topography that would otherwise make sensible building impossible. What is decisive is that the constraint comes from the plot and not from the project.

• Usually counts: The particular character of the building project, for instance where an existing building volume is replaced or an existing gap in the built fabric is closed.

• Usually counts: An existing building already within the setback area to which the new work sensibly connects.

• Does not count: Economic hardship. The wish for more floor area, more flats or a better return does not establish special circumstances.

• Does not count: An argument that applies equally to many plots at the forest edge. What applies generally is by definition not special.

• Does not count: An already far advanced state of planning. The fact that you have already invested is no reason to grant relief from a regulation.

10. Worked example: what the forest setback costs in building land

The following example calculation shows how strongly the forest setback affects the building volume. It is deliberately simplified and serves to indicate the order of magnitude, not to design a project.

Starting point: a rectangular plot of 40 by 25 metres, that is 1000 square metres, in a two-storey residential zone with a utilisation ratio of 0.45. Arithmetically that would be 450 square metres of chargeable floor area. The forest adjoins along the long side.

Situation	Setback area	Remaining building area	Realistically achievable floor area
No forest	0 m	1000 m2	around 450 m2
Forest setback line at 15 m	600 m2	400 m2	around 450 m2, still achievable
Forest setback line at 20 m	800 m2	200 m2	around 300 to 400 m2, the building plot becomes tight
Setback of 30 m (outside the building zone)	1000 m2	0 m2	cannot be built on

The point of the calculation: up to a certain depth the forest setback only costs design freedom, after that it costs floor area, and beyond a certain depth it costs the entire plot. Where this tipping point lies depends on the geometry, not on the area. A narrow, deep plot copes with a forest setback considerably better than a broad, shallow one.

All values are guide figures, as at August 2026, and depend on the canton and on the project. How the permitted density is calculated in the first place is explained in the article on the utilisation ratio, GFZ and BMZ. What can be got out of the remaining land is shown by a feasibility and volume study that factors in the setback area from the outset.

11. Five mistakes that become expensive at the forest edge

1. Buying a plot at the forest edge without opening the zoning plan. Looking at the GIS and the OEREB cadastre costs nothing and a quarter of an hour. Not doing so costs the entire plot in the worst case. What else needs to be checked before purchase is set out in the article buying land in Switzerland.

2. Working with 30 metres although the line lies closer. The mistake works against you and costs building volume you are entitled to. Within the building zone area the line applies, not the rule of thumb.

3. Speculating on the exemption. Never buy a plot on the assumption that falling below the minimum will be permitted. It is the exception and is tied to narrow conditions.

4. Involving the forestry service too late. A forestry service that is presented with a finished project says no. A forestry service that helps develop the position looks for a solution with you.

5. Forgetting the underground options. Where little is possible above ground, the leverage shifts below ground level. Section 262 para. 2 PBG leaves room here that many designs never even examine.

12. Frequently asked questions about the forest setback

How large is the forest setback in Switzerland? Federal law does not name a figure but requires an appropriate minimum distance in Art. 17 para. 2 WaG. The cantons set it, and the values differ widely: Zug 12 metres, Schwyz and St. Gallen 15 metres, Aargau 18 metres, Thurgau 25 metres, Schaffhausen 10 metres in the building zone and 30 metres outside. In the canton of Zurich a distance of 30 metres applies outside the building zone area; inside it, the forest setback line entered in the zoning plan applies.

Does a forest setback of 30 metres always apply in the canton of Zurich? No, and that is the most common misconception. The 30 metres under section 262 para. 1 PBG apply outside the building zone area. Inside the building zone, only the forest setback line in the zoning plan is decisive. It is usually drawn at 30 metres, but under section 66 para. 2 PBG it can be placed closer to the forest or further away from it where there are small forest plots or particular local circumstances.

May I build a basement within the forest setback? In principle yes. Section 262 para. 2 PBG exempts underground structures and parts of buildings as well as structures from the forest setback. Open balconies without supports may additionally project 2 metres into the setback area under para. 3. Under forestry law the intervention still has to be assessed, above all because of the root zones and the site access during construction.

Can I obtain an exemption from the forest setback? Only where special circumstances exist, and two permits are needed: the planning law exemption permit from the municipality, in the canton of Zurich under section 220 PBG, and the cantonal consent under forestry law pursuant to Art. 17 para. 3 WaG. Special circumstances are the geometry and topography of the plot or the particular character of the building. Economic hardship alone is not enough.

Where exactly is the forest setback measured from? From the forest boundary under forestry law, not from the visible tree stand. If the boundary has not been laid down in a legally binding way, a forest determination under Art. 10 WaG clarifies where the forest begins. In the canton of Zurich it is issued by the responsible district forester of the Forest Division on application by the landowner.

What happens if my house is already within the forest setback? Existing buildings enjoy the protection of existing rights and may be maintained and modernised within their previous scope. For a replacement new build on the same site the starting position is considerably better than for a new build on undeveloped land, but it remains a decision in the individual case. Volume and position have to be derived carefully and coordinated early with the municipality and the forestry service. How much can be got out of it is shown by a feasibility study.

Assessing building land at the forest edge correctly

I clarify the forest setback line, the forest boundary and exemptions before you buy or plan. Free initial consultation.

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