Sources
Sources, and their age
A federal geoportal will draw you a register from 2000 and a reading from ten minutes ago in the same crisp style, and nothing in the picture says which is which. For a map meant to be usable as evidence that is the defect that matters most: not a wrong number, but a number whose age is invisible.
Data states are read from the federal legend endpoints at build time, refreshed every Monday, and read again in your own browser when this page opens, so a date that moved since the last build is corrected here. Nothing on this page is remembered; all of it is fetched.
Every source, on one axis
Each bar starts at that source's own published data state and runs to today. The bars are read against one axis, which is the only form in which a nine-year-old register and a ten-minute-old reading can be compared at a glance.
What is old, and why it matters
Age is not automatically a defect, and the two oldest sources here show why the question has to be asked one register at a time.
The residual-flow register of existing abstractions carries a data state of 01.01.2004: a licence granted, altered or restored since then is not in it. The treatment-plant survey is from 2011 under a data state of 01.01.2014, the nuclear-site register from 2019, and the modelled river network from 2019.
A source is marked as stale on this site when it is more than five years old. That threshold is a convention and not a legal one; it is set where it is because a federal register that has not moved in five years has usually stopped being maintained rather than stopped changing.
The full list
Holder, class, published data state, age and licence for everything the map draws. Every row links to its source; composite rows link each underlying dataset. Dates are fetched from the federal legend endpoints, so a source update appears without a copy edit.
The twenty-six deliveries
The drinking-water protection zones have no federal layer. What exists is geodienste.ch, a joint service of the cantons and swisstopo, which aggregates each canton's own delivery of the minimal geodata model Planerischer Gewässerschutz into one national service. That is the layer the map draws.
A national picture assembled from twenty-six deliveries has a currency problem that no single data state can express: it is as old as its oldest contributor, and the picture does not say who that is. So every canton's delivery date is read from the service's own register, and this site states the oldest with the canton named.
Only zones in force are drawn. geodienste.ch serves planned and future zones too, and a planned zone is not yet a legal constraint. S1 is the fenced ground at the wellhead, S2 the close zone, S3 the outer one — Art. 20 GSchG and GSchV Annex 4 No. 1. They are measured in hectares, so at country view they are smaller than a pixel. Liechtenstein shares the service and is not a canton; it delivers nothing here and is counted separately rather than into a coverage figure it would make wrong either way.
Licences and attribution
Each source is used on its own terms, listed against it in the table above. In summary: the federal datasets are published through opendata.swiss and require attribution; swissNAMES3D is swisstopo open data, free use with source attribution; HydroRIVERS is published by the HydroSHEDS project of WWF under its own licence, free for non-commercial and commercial use with attribution; the cantonal protection zones are freely available over WMS from all twenty-six cantons through geodienste.ch.
This site adds two things to that material and neither is a new measurement: the propagation of a measured value onto a river network, and the statement of every source's age beside the source. Both are described on the method page.
Statute and ordinance are quoted from the consolidated German texts on fedlex.admin.ch in the versions in force on 21 August 2026. Case law is cited to the published reports. See the legal layer.