A swimmer's guide to some of the purest water in England

Wild Swimming Author Kate Rew testing the water at High House Tarn, Lake District, England

Water, rock, wind and sky: amidst the peaks and crags of the Lake District lies some of the purest water in England: 137 tarns and 16 lakes are dotted into uplands and lowlands like shiny pins on a map.

Wild tarns hold a natural allure for wilderness seekers, explorers and dreamers. In 2009, after publishing Wild Swim, I went off to live in the Lake District for a summer, with the mission of writing a second book that would bring each mountain pool to life. 

Each day I walked and swam: from remote upland tarns where the water is cold and clear and mountain birds circle in the clean air, to lowland lakes where the boundary between woodland and wetland fluctuates with every fresh rainfall. 

Tarns are associated with the highest fells, with wilder, more remote places, and for me were always a better focal point for a walk than a lake or a summit. While summits can feel like an anti-climax – crowded, wind-whipped, littered, cold – tarns carry every aspect of feeling like a prize on arrival. They invited me to pause by them for a little while, to get in and experience the water.  To feel the slap of tarn after tarn – always cold, sometimes bitter.


It was an amazing summer of self-drowning dragonflies and murderous ospreys, dizzying summits and inland beaches, in a land that runs gloriously amok from it’s keepers. I sweated my storm-whipped way to these high pools in a carnival of experience, threw off my clothes and jumped in. I gasped and sighed as surely as ice and sun crack open rocks on the summit, streaking down headwaters and sitting with damson flies. 

My notes have never made it out of my notebook (my enthusiasm to get going meant I was gone before realising my editor wanted a completely different book to the one in my vision) but inspired by and in honour Rory Southworth’s 2020 #deepwaterproject, to swim the 20 deepest tarns in the Lake District over winter, I have turned to W Heaton Coopers classic book ‘The Tarns of Lakeland’ and a flicker of memory to describe enough of the territory for swimmers to plan their own journeys around some of these tarns. (Heaton Cooper was a beloved guide to me also, over that summer). The notes below are thin – leaving you with plenty of space for wonder. And, helpfully, keeping you out of the shallowest, boggiest water. 

Be careful to avoid contaminating lakes and tarns – for further information, read “Spread the word not the weed”.

John-Paul Walsh

Stickle Tarn

There are two Stickle Tarns, and for depth swimmers want the one in the Langdale valley. ‘This south facing corrie is a veritable sun-trap’ writes Heaton Cooper. ‘There are several places below the scree where one can dive from great boulders into the clearest and iciest of green depths, fed from cisterns far in the mountain’.

Levers Water

A small lake above Coniston with an average depth of 8m, this naturally occurring tarn was enlarged in 1717 to provide water for the local copper mines. The tarn is surrounded by the wonderfully named Raven Tor to the south-west and Swirl How to the east. 

Scoat Tarn

Among the higher tarns, hidden to the west of Wasdale. “Scoat comes from ‘skuti’, Old Norse for ‘projecting crag’,” says Heaton Cooper. This tarn is small and deep, sitting in a corrie scooped out by glaciers, and drains in Wastwater via Nether Beck. 

Red Tarn

There are two Red Tarns, one in the Helvellyn and one in the Langdale valley. The deepest one is Hevellyn. Heaton Cooper visited this one in the dark too: “The long trudge up the western slopes in semi darkness is enlivened by the sense of light slowly increasing. From the summit ridge Ullswater is seen winding away like  a great river towards the rising sun, and… Red Tarn picks up.. some of the easter glow with, perhaps, a morning star dimly reflected in it’s dark waters”.

Grisedale Tarn

One of the deeper tarns, Grisedale is also ‘one of the windiest of them all’ says Heaton Cooper, who records a few quick swims. Sat above Grasmere, the tarn has a maximum depth of 33 m and is nestled betwen Fairfield and Dollywagon Pike. 

Blea Water and Small Water.

Roughly circular and at over 60 m deep, Blea Water is the deepest tarn in the Lake District. Near to Blea Water is Small Water – ‘One of the most lovely of all the corrie tarns in the district,’ says Heaton Cooper.

Easedale Tarn

An easy ramble up from Grasmere, Easedale makes a good swimming and picnic spot for children, and flows into Sourmilk Gill, named after it’s milky coloured waterfalls. 


A corrie tarn at the foot of the Old Man of Coniston. ‘When the wind blows hard from the north west it is sometimes funnelled between the mountains, and I have been there when the whole surface of the tarn has been blow along till it overflows the boulders at the outlet, when whirlwinds of spray have gone twisting a thousand feet into the sky above Dow Crags.’ 

Low Water

A rare thing, a high comb tarn. To Heaton Cooper Low Water was “an ominous place, with all it’s tones dark and muted, and usually in shadow by the time small feet have carred me so far.. I have been up there when the wind roared and screamed in the crags.. on a still sunny morning in February after a night of frost, the strange silence would suddenly be shattered by an enormous groan ending in a crack as the ice on the tarn gave way to the strengthening sun.’ 

Burnmore Tarn

On Eskdale Fell, the third largest tarn in Lakeland. ‘It is very shallow at the north end, but regularly fairly steep along the south-east shore, falling to 40 ft in 300 feet at one part’ says Heaton Cooper, who adds, ‘I do not find Burnmoor a pleasant or delightful tarn, but rather stern, almost forbidding in dark weather.’ 


Blea Tarn

One of the easier tarns to visit, between Little and Great Langdale. Now a SSSI. ‘Blea’ is derived from dark blue, and the tarn is renowned for sediments at the bottom of the tarn undisturbed since the Little Ice Age.

Devoke Water

An exposed moorland tarn, one of the largest of all the tarns in the Lake District. ‘I do not know any part of the Lake District which is so like the Scottish Highlands in it’s broad heather moors,’ says Heaton Cooper. 


This tarn lies in a high glaciated U shaped valley with a definite step, in the Patterdale Valley.  A naturally occuring tarn, it was dammed in 1908 to provide water for Penrith.

Loughrigg Tarn

One of my favourite tarns for a quick dip, Loughrigg is a lowland tarn and hop skip and jump from the road, just north of Windermere.

Dave Pye

Bowscale Tarn

In the Blencathra range, above Mosedale off the A66 between Keswick and Penrith, and, according to folklore, home to two immortal fish. ‘The crag is almost always against the light.. so it is not surprising that Bishop Nicholson wrote in 1705 ‘So cold yt nothing lives in it.’ 


Watendlath Tarn

Watendlath Tarn hs a maximum depth of 17 m, with its water feeding into Derwent Water vian Watendlath bBeck. A pretty tarn in a hanging valley in Borrowdale. 

Seathwaite Tarn

A reservoir in the Furness fells, the existing tarn was enlarged with a damn in 1904. The tarn has a maximum depth of 24 m, and is the third largest tarn in the Lake District. 

Kate Rew is the Founder of and Creative Director for The Outdoor Swimming Society. Kate grew up swimming in rivers in Devon, swam all over the country for her book, Wild Swim, and now lives  with her husband and children in Somerset. Signed copies of Wild Swim (Kate Rew) are available in the OSS shop.


Remember to #spreadthewordnottheweed – be careful not to cross-contaminate lakes and tarns via swimsuits and wetsuits. Key advise is to:

  • Check your equipment and clothing for living organisms. Pay particular attention to damp or hard to inspect areas.
  • Clean and wash all equipment, footwear and clothes thoroughly. If you do come across any organisms, leave them at the water body where you found them or on a hard surface to die out.
  • Dry all equipment and clothing. Some species can live for many days in damp conditions.


Kate Rew