Is the soil polluted? Polluted sites, gardens and playgrounds
Old landfills, shooting ranges, and commercial and industrial sites can have polluted the soil with pollutants. Lead or other pollutants are also sometimes found in gardens and on playgrounds. The cantons keep a public register of polluted sites. Before a property is entered in it, those affected may comment. An entry does not mean that the site must be remediated. As a rule, the costs are borne by whoever caused the pollution. Anyone who wants to sell or divide a registered property needs authorisation. Anyone buying a property should check the register beforehand.
Reviewed by a lawyer on 30 September 2026Official sources
Watch out
Before the authority enters a property in the register, it must tell the holders what it intends to enter. They are given the opportunity to comment and to make their own enquiries. Use this opportunity. Check the details carefully: are the location, the former use and the period correct? Note the time limit stated in the letter. If you do not agree with the entry, you can request a declaratory ruling. This is a formal decision on the entry, which you can challenge with a legal remedy. The Federal Supreme Court has confirmed that the authority must issue such a decision on request, including later when it is about changing or deleting an entry. An entry is deleted if the investigation shows that the site is not polluted, or if the pollutants have been removed. If the investigation of a site that is entered, or intended for entry, shows that it is not polluted, the public authority concerned bears the costs of that investigation.
AltlV · Art. 5BGer 1C_556/2020 vom 25. November 2021, E. 1.2AltlV · Art. 6USG · Art. 32d
Even someone who acquired an already polluted property and did not pollute it themselves may have to bear part of the costs. The Federal Supreme Court generally counts such owners among the possible persons responsible. They are released only if, taking the care required, they could not have known about the pollution. What matters is the point in time of acquisition. Anyone who knew of indications at that time, or should have known of them, cannot rely on being unaware. Such indications can arise from the land-use plan, the land register, the register of polluted sites, or the former use of the property. But someone who is not released does not automatically bear a large share. According to case law, a noticeable share is only justified if further circumstances are present, for example if the person was already responsible at the time of the pollution, or gained an economic advantage from it. Have a costs ruling that imposes a share on you reviewed before the time limit for a legal remedy expires. This time limit is stated in the instructions on legal remedies in the ruling.
USG · Art. 32dBGE 139 II 106, E. 3.6BGE 139 II 106, E. 5.6BGE 142 II 232, E. 4.3
If the company or person that polluted the soil can no longer be found, or is insolvent, their share of the costs does not stay with you. Under the law, the responsible public authority bears this share. The Federal Supreme Court also applies this where a known person responsible has since disappeared without a successor. Even so, you should expect some effort on your part: the work generally has to be carried out by whoever holds the site. This means you have to instruct specialists and expect to settle invoices yourself at first. How much you ultimately bear yourself is only fixed by the ruling on the allocation of costs. Request this early. You may still bear a share of your own if, as owner, you should have known about the pollution. If you are not in a position to arrange the work, the canton can have it carried out itself. Ask the cantonal environmental agency exactly how your canton handles advances, contributions and the final accounting.
USG · Art. 32dBGE 142 II 232, E. 6.5AltlV · Art. 20USG · Art. 32c
Anyone who wants to sell or divide a property on which a site entered in the register is located needs authorisation from the authority for this. It is granted if no harmful effects or nuisances are to be expected from the site, if the costs of the measures to be expected are secured, or if there is an overriding public interest in the sale or the division. Plan for this authorisation early, so that the sale or the entry in the land register is not delayed. The canton can also have the register entry noted in the land register. The authority can also require a person responsible to secure their probable share of the costs in a suitable form, if harmful effects are to be expected. Your canton regulates how the application proceeds and which body is responsible. Ask the cantonal environmental agency or the notary.
Important to know: anyone who is simply concerned about the environment or other people's health cannot force the authority to investigate or remediate a site. Making a report or demanding action does not make you a party. An appeal in the interest of the general public, often called a popular appeal, is not permitted. Only someone who is more affected than the general public and has their own personal benefit from the proceedings has more rights, for example the owner of the affected property. Nevertheless, the following are effective: a well-founded report to the cantonal environmental agency, questions to the municipality, a request to inspect measurements and investigation reports, and, if nothing happens, a supervisory complaint to the supervisory authority, which your canton regulates.
What to do
Here is how to proceed if you suspect pollution in a garden or on a playground: check on your canton's geoportal whether the area is listed in the register of polluted sites or on a guidance map for soil pollution. Ask the cantonal environmental agency whether measurements exist for your area and whether a soil sample makes sense. For allotment gardens, the garden association or the municipality, as owner, is often informed too. Follow any restrictions on use that the canton has ordered. As long as you do not know more, the rule is: ask the specialist agency before growing a lot of vegetables for your own use, or letting young children play often on open soil. If you have health concerns, speak to your doctor.
The law
Every canton keeps a publicly accessible register of polluted sites, the so-called register. A place is polluted if waste has entered the soil there: a former landfill, a site where hazardous substances were handled, or a place where an accident happened. A site is entered in the register once the pollution is established or very likely. The authority then classifies the sites: for some, no harmful effects are to be expected. For others, it must be investigated whether they need monitoring or remediation. So an entry does not yet mean that there is a danger or that remediation is needed. A site only requires remediation once it harms, or concretely threatens to harm, people or the environment, for example the groundwater, a stream, the air or the soil. Only such a site counts as a contaminated site. After the investigation, the authority records in the register whether the site needs monitoring, whether it is a contaminated site, or whether neither applies.
If a registered site needs to be investigated, the authority requires a preliminary investigation within a reasonable time limit. This usually has two parts: first, records and plans are used to establish what happened on the site in the past. Then samples are taken to measure which substances are present and in what quantity. The measurement programme must be submitted to the authority for comment. On this basis, the authority decides whether the site needs monitoring or remediation. The investigations and remediation must be carried out by whoever holds the site, usually the owner. But the authority can also require third parties who caused the pollution to do so. For the remediation itself, it needs the consent of the holder. If the person required to act does not do so despite a reminder and a time limit, is unable to do so, or if harmful effects are imminent, the canton can carry out the work itself or instruct a third party to do so. The authority sets the time limit for an investigation in the individual case. Observe it, and get in touch early if you cannot meet it.
Before buying, check whether the property is in the register of polluted sites. The register is public. Many cantons show it on their online geoportal. This matters because you cannot later rely on being unaware if you knew of indications of pollution when buying, or should have known of them. In that case, part of the costs can stay with you. Also ask about the former use, for example a workshop, a petrol station or landfilling. If you want to build or rebuild on a polluted site, this is only allowed if the site does not require remediation and will not come to require it because of the building project, or if a later remediation is not made significantly more difficult. Otherwise, the affected part must be remediated at the same time. This can make building more expensive. Get advice before signing on how the purchase contract should deal with the costs of pollution.
Even outside landfills and industrial sites, the soil can contain pollutants such as lead, other heavy metals or PAHs. PAHs are substances produced by combustion, for example from soot, ash or tar. Where such pollution is established or likely, the cantons draw up guidance maps. They also publish the results of their monitoring. The soil is assessed against values that the Confederation sets in an ordinance. There are three levels. If the guide value is exceeded, the canton looks for the cause. If the trigger value is exceeded, it checks whether people, animals or plants are concretely at risk, and restricts use where necessary, for example growing vegetables. If the remediation value is exceeded, the canton prohibits the affected uses. In areas designated for horticulture, agriculture or forestry, it orders measures so that the soil can be used safely again. Which values apply depends on the use, for example whether food crops are grown there or whether children come into direct contact with the soil.
VBBo · Art. 4VBBo · Art. 5VBBo · Art. 8VBBo · Art. 9VBBo · Art. 10USG · Art. 34
Since 1 April 2025, a special rule has applied to places where young children play. The cantons must ensure that public children's playgrounds and public green spaces are remediated if their soil is polluted with environmentally hazardous substances, if young children regularly play there, and if harmful effects exist or concretely threaten to arise. This duty to remediate does not apply to private playgrounds and private house gardens. It is different only if the garden is part of a polluted site, for example a former landfill: then the general rules for such sites apply. However, the cantons can provide financial support for remediating private playgrounds and house gardens if young children regularly play there and the polluted soil is harmful or concretely threatens to become so. Whether and how your canton grants such contributions is for it to decide. The Confederation contributes to the costs of many investigations and remediations through payments to the cantons. If you are worried about a public playground, contact the municipality or the cantonal environmental agency and ask whether the soil has been investigated.
If you suspect old pollution that is not listed in the register, for example a former pit that was filled in, an old shooting range or a former business, you can tell the cantonal environmental agency. The authority identifies polluted sites by evaluating maps, registers and reports, and can obtain information from holders and third parties. Describe what you know and where it comes from: old photos, plans, accounts, smells or unusual material in the soil. If it is about fresh pollution or waste that is currently being illegally dumped, read the guide on environmental pollution: it covers the emergency number and reporting an offence.
The register of polluted sites is publicly accessible. Many cantons show it online on their geoportal. The cantons also publish the results of their soil monitoring. The authorities must inform the public about the state of environmental pollution, and the environmental agencies also advise private individuals. So you may ask there what is known about your property, your garden or a playground. If you want to inspect investigation reports or measurement results, ask in writing. Overriding private or public interests in confidentiality, such as business secrets, remain protected, however.
Costs
The costs of necessary investigations, monitoring and remediation are borne by whoever caused the pollution. The law thereby follows the principle that whoever makes environmental protection measures necessary must pay. If several people are involved, the costs are divided according to their shares of responsibility. The person who caused the pollution through their conduct pays first, for example the business that deposited waste. Anyone who is merely the holder of the site pays nothing if, even taking the care required, they could not have known about the pollution. According to case law, if someone can be released from liability in this way, their share is allocated to the other persons responsible, not to the general public. The authority sets out who bears which share of the costs in a ruling on the allocation of costs. It must issue this ruling if a person responsible requests it, or if it carries out the measures itself. You can challenge this ruling. If the investigation shows that a site that is entered, or intended for entry, is not polluted at all, the public authority concerned pays for the investigation.
Advice
Get personal advice if the authority demands an investigation or remediation from you, if you receive a ruling on the allocation of costs, or if you want to buy, sell or build on a registered property. Large sums are often at stake here, and time limits for legal remedies are short. A lawyer experienced in environmental or construction law can assess whether you can rely on being unaware, and who else might be considered a person responsible. For technical questions, such as taking samples, a specialised environmental consultancy is generally needed. When buying or selling, the notary can help to deal with the pollution in the contract.
Help
Free points of contact: your canton's environmental agency, often called the office for the environment, answers questions about the register, soil pollution and investigations. You will usually find the register of polluted sites on your canton's geoportal. Your municipality knows who owns public playgrounds and allotment gardens, and whether measurements have been taken there. The Federal Office for the Environment gives a general overview of polluted sites and soil protection on its website.
Scope
Sites polluted by waste, such as former landfills, operational and accident sites, and shooting ranges; the cantonal register of these sites; the right to comment before an entry is made; investigation and remediation; the allocation of costs; authorisation for sale and division; building on polluted sites; and polluted soil in gardens, allotment gardens and children's playgrounds.
Not covered: Fresh pollution and illegally dumped waste that you want to report (there is a separate guide on environmental pollution for this), pollutants in buildings such as asbestos, disputes between neighbours, civil-law claims under a purchase contract in detail, and the liability of heirs.
Sources
Statute texts checked on 30 September 2026.
USG · Art. 10e
Umweltinformation und -beratung
1Die Behörden informieren die Öffentlichkeit sachgerecht über den Umweltschutz und den Stand der Umweltbelastung; insbesondere: a. veröffentlichen sie die Erhebungen über die Umweltbelastung und über den Erfolg der Massnahmen dieses Gesetzes (Art. 44); b. können sie, soweit dies von allgemeinem Interesse ist, nach Anhören der Betroffenen veröffentlichen: 1. die Prüfergebnisse der Konformitätsbewertung serienmässig hergestellter Anlagen (Art. 40), 2. die Ergebnisse der Kontrolle von Anlagen, 3. die Auskünfte nach Artikel 46.
2Vorbehalten bleiben überwiegende private und öffentliche Geheimhaltungsinteressen; das Fabrikations- und Geschäftsgeheimnis bleibt in jedem Fall gewahrt.
3Die Umweltschutzfachstellen beraten Behörden und Private. Sie informieren die Bevölkerung über umweltverträgliches Verhalten und empfehlen Massnahmen zur Verminderung der Umweltbelastung.
4Die Umweltinformationen sind wenn möglich als offene digitale Datensätze zur Verfügung zu stellen.
Official text, in German · Open on Fedlex · Statute texts checked on 30 September 2026.