Checking Contaminated Sites & Polluted Land
Updated:
An entry in the register of polluted sites does not automatically mean danger — but it deserves a check. This page explains what separates a “polluted” site from one “needing remediation”, where to find a parcel's entry, and what it means for a transfer, financing or conversion. Factual, not alarmist.
This page explains publicly accessible registers and does not constitute tax, legal, construction, or financial advice. Consult a qualified professional for legal or tax questions.
Why polluted sites matter when checking a property
An entry does not decide livability, but it does shape possible duties and costs when you rebuild or change use. Knowing it before a transfer or financing lets you plan calmly instead of being surprised later.
What a polluted site is
A polluted site is a place whose soil is polluted by waste — for example a former landfill, a former industrial site, or an accident location. “Polluted” does not automatically mean “dangerous”: the register of polluted sites expressly distinguishes a polluted site from one needing remediation.
Source: Register of polluted sites (FOEN) · Glossary: contaminated sites
Where to find the entry
Each canton keeps the register of polluted sites. The entries are publicly viewable through the map portal geo.admin.ch and the cantonal GIS portals; as a PLR theme they also appear in the PLR cadastre of an affected parcel.
Source: Federal geodata (geo.admin.ch)
Polluted, monitored, or needing remediation
The register classifies sites by need for action: no action needed, monitoring needed, or remediation needed. Only the last category counts legally as a contaminated site. For most polluted sites no measures are needed as long as the use does not change.
What an entry means when checking a property
An entry is no cause for panic, but a cause for clarification: whoever changes the use of or builds on a polluted parcel may have to investigate and bear the costs. Before a transfer or financing, clarify with the cantonal contaminated-sites office which classification applies and whether your project triggers measures.
Source: Contaminated sites, Canton of Zurich (zh.ch) · Checklist step 4: check contaminated sites
The four honesty states
Every fact in an alpflo register brief carries exactly one of these states.
Confirmed in an official Swiss register. Direct source.
Register queried; nothing on this parcel. The absence is documented.
Derived from a model or an API: real, but not directly from the register. Please verify.
Hit an edge case. Stated honestly at the boundary, never silently discarded.
Frequently asked questions about polluted sites
Is a polluted site the same as a contaminated site?
No. “Polluted” describes soil containing waste; a “contaminated site” is a polluted site that demonstrably causes harmful effects and therefore needs remediation. Most polluted sites are not contaminated sites.
Where do I find out whether a parcel is polluted?
In the cantonal register of polluted sites, publicly viewable through geo.admin.ch and the cantonal GIS portals. As a PLR theme, the entry also appears in the parcel's PLR extract.
Do I have to remediate a polluted site?
Not necessarily. A duty to remediate exists only if the site is classified as needing remediation. With unchanged use, no measures are required for many entries — a rebuild or change of use can, however, change that.
Who bears the investigation costs?
That follows the polluter-pays principle and cantonal practice. Clarify the cost question before a transfer or financing with the cantonal contaminated-sites office — an entry can trigger investigation or remediation costs.
Read next
What the public registers hold for an address — the parcel, the PLR cadastre, building data — alpflo compiles on request into a register brief for a specific property, every fact with its official source. Invoiced. A brief is written in German or French, for a German- or French-speaking commune — there is no English edition.
On request · invoiced · every fact with its source.