How we know
WhereToSwim.eu shows the current bathing-water status of 959 swimming spots across Ireland and the United Kingdom. Every figure on the site comes from a national monitoring body. This page explains which one, how the status is worked out, and what it cannot tell you.
Where the data comes from
We publish no measurements of our own. Every classification, sample and alert is republished from the agency responsible for that water, and each spot page names the agency its figures came from.
| Source | Covers | What it provides | Licence |
|---|---|---|---|
| Environmental Protection Agency (Ireland) | 248 bathing waters in Ireland | Locations, annual classifications, sample results, pollution alerts, official descriptions and an amenity layer | CC BY 4.0 |
| Environment Agency (England) | 464 bathing waters in England | Locations, annual classifications, in-season samples, short-term pollution forecasts, advice against bathing and open pollution incidents | Open Government Licence v3.0 |
| Natural Resources Wales | 114 bathing waters in Wales | Locations, annual classifications and sample assessments. Rainfall from NRW gauges also feeds our own run-off estimate | Open Government Licence v3.0 |
| Scottish Environment Protection Agency | 90 bathing waters in Scotland | Locations, annual classifications, and a daily signage forecast for the 33 sites with electronic signs | Open Government Licence v3.0 |
| DAERA (Northern Ireland) | 33 bathing waters in Northern Ireland | Locations only. DAERA publishes bathing-water quality as seasonal reports rather than as data, so these spots carry no status | Open Government Licence v3.0 |
| OpenStreetMap contributors | Parking and toilets near 701 UK spots | Amenities the national agencies do not publish, each recorded with its distance from the spot | ODbL |
| Open-Meteo | Sea temperature, wave height and tide | Modelled marine conditions, not measurements taken at the beach itself | CC BY 4.0 |
| English water companies, via Water UK's Stream portal | 14,201 storm overflows across nine companies in England | Whether each overflow is discharging right now, as the company reports it. Shown as context near a spot and never used to set its swim status — Wales and the other nations publish no live equivalent | CC BY 4.0 |
How the status is calculated
Inputs are applied in order of severity and the first that matches wins. A spot can never be marked green on thin data — missing information degrades to grey, never to reassurance.
- Do not swim
- An agency has an active prohibition or a standing all-season restriction in force, or a council or landowner advises against swimming year-round.
- Caution
- A short-term pollution forecast is in force, the most recent sample was rated Poor, or the annual classification is Poor or Sufficient.
- Good to go
- No active alert, and the annual classification and recent samples are Good or Excellent. It means no warning is in force — not that the water was tested today.
- Not monitored
- Either the spot is not a designated bathing water, or it is designated but its agency publishes no results we can read. We would rather say nothing than guess.
How often it updates
Every source is re-read hourly, and each spot page states when it was last checked and when its data last actually changed — two different facts, kept separate on purpose. Rain gauges in Wales are read every fifteen minutes. The most recent check across the whole site was .
If you sign up for alerts
Watching a spot stores your email address and which spot you asked about, nothing else — no name, and not your IP address. It is used to send those alerts and for nothing else, is never shared or sold, and there is no newsletter. We confirm by email first, so an address cannot be signed up by someone else.
Every email carries a one-click unsubscribe link. Using it deletes the record immediately — there is no dormant copy kept. The one honest caveat: encrypted nightly database backups are retained for a few months, so an unsubscribed address survives in those until they age out. Anything you want removed sooner, or a copy of what we hold, write to hello@wheretoswim.eu.
An alert relays what a monitoring body published. Like every other figure on this site, it is not a clearance to swim.
What this site cannot tell you
These limits are real, and we would rather state them than let a green badge imply more than it means.
- It is not a safety clearance. The badge reports what the monitoring bodies have published. It is not permission to swim, and conditions change far faster than any monitoring programme.
- Water quality is not the only danger. Rip currents, cold-water shock and tides are unaffected by how clean the water is, and they are what most often causes harm.
- Samples are periodic, not continuous. A classification is a percentile across four bathing seasons. A sample describes only the day it was taken.
- Northern Ireland has no status. DAERA publishes quality as seasonal reports rather than as data, so all 33 spots there are grey however clean the water is.
- Wales cannot show a prohibition. NRW publishes no machine-readable advice-against-bathing feed, so if advice is issued at a Welsh beach this site will not show it.
- Marine conditions are modelled. Sea temperature, waves and tide come from a forecast grid, not from the beach. Use official tide tables for anything needing precision.
- Rainfall amber in Wales is our inference. NRW measures the rain; the conclusion that run-off may affect bathing water is ours, and no agency has issued advice on that basis.
Corrections
If something here is wrong — a spot in the wrong place, a status that contradicts a sign on the beach, or an agency credited incorrectly — tell us at hello@wheretoswim.eu and we will fix it. Where this site disagrees with a sign at the water’s edge, believe the sign.