Recent media stories have led to much confusion, especially between ecological water quality measures and bathing water quality. Exaggerated headlines have suggested that no river is fit to swim in, based on the fact that no rivers are designated as bathing waters. I suggest considering pros and cons and practicalities before setting up campaigns for designated bathing waters at swim spots. (Designated Bathing Waters explained – what they are and why they matter)
In practice, most swimmers can look at the water and can assess instinctively if it is clean enough to swim or dip in. The Outdoor Swimming Society’s Is It Clean? gives some tips: avoid inner city water, places with litter or debris, murky water or scum, or that smell bad. And avoid swimming after heavy rain, particularly downstream of grazing cattle and of water treatment works – which are mapped by the Rivers Trust (opens large interactive map), as part of their campaign for Rivers Fit To Swim In.