Where the data comes from

Government and regulators

Bathing water designations, annual classifications, in-season sampling, daily pollution risk forecasts, pollution incident notices and tide gauge readings come from the Environment Agency, Natural Resources Wales, the Scottish Environment Protection Agency, and the Department of Agriculture, Environment and Rural Affairs in Northern Ireland.

Contains public sector information licensed under the Open Government Licence v3.0.

Contains Natural Resources Wales information © Natural Resources Wales and Database Right. All rights reserved.

This uses Environment Agency flood and river level data from the real-time data API (Beta).

Ireland

Bathing water restrictions and sample results come from the Environmental Protection Agency and the local authorities, through beaches.ie. Tide predictions come from the Marine Institute, under CC BY 4.0.

Water companies

Live storm overflow status comes from the eleven water companies that publish it: Anglian Water, Northumbrian Water, Severn Trent, Southern Water, South West Water, Thames Water, United Utilities, Wessex Water, Yorkshire Water, Welsh Water and Scottish Water. Each publishes its own data under CC BY 4.0.

Weather, sea and tide

Weather data by Open-Meteo.com, under CC BY 4.0. That covers rainfall, the seven day forecast, wind, sea temperature, wave and swell, and the modelled sea level this site uses for the tide in Britain.

Maps and places

Map data and waterfall locations © OpenStreetMap contributors, available from https://www.openstreetmap.org/ under the Open Database Licence. County outlines come from the Office for National Statistics under the Open Government Licence, and from OpenStreetMap.

What has been done to the data

It has been changed. That is the point of the site, and the licences require it to be said plainly. Readings from many sources are combined into one verdict for each place. Spill records are counted into windows. A tide curve becomes a sentence like “going out, low around 14:50”, and in Britain that curve is shifted by an offset worked out from the nearest tide gauge. Sea temperature and wave figures are dropped entirely where the nearest point the model holds is more than twelve kilometres away. None of this is the responsibility of the people who published the original data.

The sources make no warranty about their data, and neither does this site. Data is provided as it is found.

Photographs

Photographs come from Wikimedia Commons and are credited individually on the page they appear on, with the photographer and the licence.

This site

Can I Swim? is not connected to any of the organisations above, and nothing here is endorsed by them. It is one person reading what they publish. The code that collects the data is open source.