Before entering open water it is advisable to carry out your own risk assessment. This list is to help you do this. However it is just a guide and cannot be comprehensive for every situation. If you are unsure choose a nearby traditional swimming place or speak to a local swimmer about hazards - even better swim with one. Always be cautious,  as accidents spoil wild swimming for yourself and others. If you are not sure find another safe location to swim. 

This guide was produced from Rob Fryer's Wild Swimming Safety Guide.

See our winter swimming page for the extra hazards associated with swimming in very cold water.

Ensure you can get out before you get in

This is pretty obvious and particularly applies to rivers. Check the river bank downstream from your entry point. Will you be able to get out if the current takes to away from your entry point? 

No Alcohol or Drugs

Drinking and drugs are a major contributing factor in many drowning. Never drink or take drugs before you swim. 

Cold Shock

"He never came up." Is the water cold? If so, and you jump in, you may involuntarily breath in underwater and drown. Safer to walk in from shallows.

Stealth chilling and after drop

If you stay in the water too long you may become very cold and develop hypothermia. You may not realise this when you are swimming. Limit your swimming times. You will also continue to cool down after you swim, so always have warm cloths available to put on immediately after your swim and a hot drink and something to eat. A wet suit will allow you to swim longer.

Faulty estimate of your ability and/or condition

"He got into difficulties" Considering swimming across a river or lake? A faulty estimate of your ability, the distance & the conditions could cost you your life. Safer to swim along the shore and get out before you cool down.

Weed Entanglement

Some water weeds can trap you. Avoid weed beds but if caught: don't panic swim downstream with your arms only.

River in spat

Brown or very fast flowing water or sticks and debris floating down are a sign of this. Fast flowing rivers will be much more difficult to swim in and you should not swim in these condition. Debris carrtied by the river may injury you. Pollution levels may be high. Do not swim  for a few days afterwards to allow pollution to run away.

Abrupt shelving or unstable bank

Does the bed shelve abruptly, or is it unstable? This could be fatal for weak or non swimmers. Find a shallow area to enter the water and check depth with foot or stick as you proceed.

Cloudy Water

"He broke his neck." If you cannot see what is under the surface do not dive or jump in. Check for obstructions before jumping in and especially diving.

Weirs and waterfalls - stoppers

Will you be swimming below a weir or waterfall where there is a midstream reverse surface current? Most likely you cannot escape. With an undercut scoured cavity you are even more surely doomed. If you do not know it is safe do not approach.

Weirs and waterfalls - stopper with scoured cavity

Will you be swimming below a weir or waterfall where there is a midstream reverse surface current? Most likely you cannot escape. With an undercut scoured cavity you are even more surely doomed. If you do not know it is safe do not approach.

Waterfalls, cascades and weirs - horizontal water rotation

Horizontal water rotation, below a waterfall, cascade or weir, takes you round to the strong current in the middle, and then downstream. Do you want this? If you do not know it is safe do not approach.

Weir sluice or rock siphon

Is there a sluice or natural “siphon” (usually upstream of a rock formation and difficult or impossible to see)? Check with canoe sites or local swimmers for the location of “siphons”. If you do not know it is safe do not approach.

Weil's desease

Do you have a cut? Worse still a cut to the face? Weil's Disease risk - low but serious risk in UK, much more so abroad, especially France. Consider not swimming or wear a waterproof plaster. Be aware of the symptoms: flu like with a sudden onset after 7 - 26 days. See your doctor and tell him/her that you a have been swimming in open water.

Fast Currents

Can you swim faster than the current? If not, you may be carried to places where you do not want to be, or become entrapped.


Do you get Cramp? Add buoyancy with a 5mm wetsuit, keep in your depth, take stretching exercises beforehand or drink plenty of tonic water with quinine (but not with gin!).

Water quality

Contact the Environment Agency to find out the rating for the location you intend to swim. Graded: A(best) to E(worst). Avoid swimming after severe rainfall as land “run off” can be polluted. Best of all swim at an EU Bathing Water site which will be regularly tested.

Blue green algae

Is there a foul smelling blue-green scum? Blue-green algae can be toxic and may cause, in some people, allergic reaction to skin, eyes and nose, and vomiting or diarrhoea if swallowed. Greater risk in stagnant or slow moving water, especially Iakes and canals. Do not swim if unsure.


Watch out for boats. Using a snorkel increases the risk. Powered craft (especially those propellers) increase the damage. Have a friend look out and wear a conspicuous hat or swim with a marker bouy.


Avoid hazard areas - rocks, shallow water. If you jump in, swim away from any hazard area before surfacing. Wear a conspicuous hat. Be aware.

Young men and not so young

Youths & young men are statistically at by far the greatest risk of drowing/injury. Calm down, do not take risks or opt for life changing surgery!


Quick Sand

Keep moving— forwards or backwards. Don’t get stuck. Do not stand and sink. Lie down and roll out of it. Well, this sounds a bit messy, but that’s what the Queen’s Guide to the Sands (Morecambe Bay) says and it assumes you value your life above a bill for laundering your clothes.