Safe Bathing Water Planner

Search by name, region (e.g. "Cornwall", "Scotland") or waterbody type. Or paste a UK postcode to jump to the nearest designated bathing water.

The UK bathing season runs May–September. Peak-risk weeks vary by month (early May and late September are slightly higher due to shoulder-season storm activity).

Wild swim and surf imply full head immersion (multiplier ×1.0). Paddleboarding and kayaking cut the ingestion multiplier to ×0.15–0.25. Paddling (feet only) sits at ×0.40.

A vulnerable user (child, elderly, pregnant, immunocompromised, IBD) doubles the baseline probability — consistent with UKHSA guidance on gastrointestinal risk sensitivity.

The calendar turns green/amber/red for each week of your chosen month. The rainfall tab shows the live 10-day forecast with the 10 mm trigger line. The map tab shows the site location and classification colour.

Short-term pollution warnings (Swimfo) and live CSO discharges (SSRS) are the final-layer checks. This planner handles pre-trip decision making; those two services handle real-time ground truth.

Under UK regulation 2013/1675, each designated bathing water is sampled weekly May–September (roughly 20 samples per season). The rolling four-year 95th-percentile values of E. coli and Intestinal Enterococci determine the classification. Coastal sites use different thresholds from inland sites. Excellent: E. coli ≤ 250 / IE ≤ 100 CFU/100ml. Good: ≤ 500 / ≤ 200. Sufficient: ≤ 500 / ≤ 185 (90th percentile). Poor: anything above — triggers a mandatory pollution management plan and advice-against-bathing signage.

Until 2021 there was no comprehensive public data on storm overflow discharges. Event Duration Monitoring (EDM) sensors have now been rolled out to over 14,000 combined sewage overflows. In 2024 water companies recorded 4.7 million hours of CSO spills across England — a 180% increase on 2023 figures (partly due to 50% more sensors, partly due to wetter winter conditions). Surfers Against Sewage's SSRS service aggregates these near-real-time feeds into a single map, and the Environment Act 2021 requires water companies to publish annual pollution reduction targets and capital investment plans.

Seawater dilution, UV sterilisation and tidal flushing give coastal sites a natural advantage. Rivers carry accumulated agricultural runoff from upstream catchments, have much lower dilution ratios, and often have poorly-sealed pre-1970s sewage infrastructure upstream. The Rivers Trust, WildFish, and Surfers Against Sewage have campaigned successfully for river designations — the Wharfe at Ilkley (designated 2020), the Teme, the Wye, the Derwent, the Dart all now have formal classification but most are currently Poor. Improvement requires slurry-management reform, sustainable drainage, and CSO elimination — decade-scale investments.

At an Excellent-rated site with settled weather, the per-session illness probability is ~0.5%, giving an expected-cost per session of ~40p. At a Poor-rated river during a post-rain window, the per-session probability can exceed 20% with an expected cost approaching £20 per session (GP visit, prescription, time off work). The best cost-benefit actions are (1) choose Excellent coastal sites, (2) wait 48+ hours after heavy rain, and (3) prefer non-immersion activities when conditions deteriorate. Over a 20-session summer this can shift total expected illness cost from £250+ down to £5–£10.

The Environment Act 2021 mandates elimination of storm overflow discharges from the most ecologically sensitive sites by 2035 and all sites by 2050 — a £56bn capital programme across the English water companies. Scotland's Water Resources (Scotland) Act 2023 imposes similar duties on Scottish Water. Wales' bathing water framework is being reviewed with NRW for integration with agricultural NVZ rules. Near-term (2026–2028), expect more river designations, mandatory live-EDM publishing for 100% of CSOs, and bathing-season extensions into October in southern England as climate shifts the swim season.