Water Sources


Posted: Wed, Aug 15, 2012, 14:57

Hello can anyone help with advice about reliability of water sources on GR 20. Walking the route south to north 26th August. It looks very hot there at the moment and am thinking about amount of water to carry, obviously want to keep weight down but don't want to suffer dehydration. Along the route sources are marked but can you rely on them to have water or do they dry up.




Posted: Thu, Aug 16, 2012, 5:20

I would not rely on them. There are but a few of them to start with, and they were smallish in early June, so many would have dried up until now. You should carry 3 liters with you, but can always empty a bottle sometime during the day if you realize you won't need that much water.


Posted: Mon, Aug 20, 2012, 15:22

I would recommend to bring with you rehydration tablets with the electrolytes, vitamins and minerals you need. I took one-two tablets per day to keep my salt level in balance.

Just remembered this post about dehydration from last year: http://corsica.forhikers.com/forum/p/6535


Posted: Mon, Aug 20, 2012, 17:15

Hi DrGT,

What is the brand of rehydration tablets you use? Have you had any luck making your own or adding "Lo-Salt" to your water bottles? The Lo-Salt is about 2/3 potassium which I understand is part of the sodium/potassium need for electrolytes.



Posted: Tue, Aug 21, 2012, 5:34

One of the people we met on the trail this year was a French cardiologist. He was quite terrified seeing me putting extra salt in my food. When I explained I needed it because of the dehydration, he answered that by eating normal food while hiking, the salt balance is kept, even in the heat. No need for extra salt, or rehydration tablets.


Posted: Tue, Aug 21, 2012, 6:59

Thanks for all your advice guys. Have done some more research re adding rehydration tablets to your water/benefits of sport drinks against plain water , some interesting facts for and against. As these tablets are flavoured I will add them to make my water palatable and any further benefits will be a bonus.
Joanna I see you have done the GR20 this year is it possible I could communicate with you direct (email) as I have a few questions about our trip starting 26th August.




Posted: Tue, Aug 21, 2012, 8:24

I am not a doctor of medicine (despite my nick) and I am sure that one safely can complete the whole GR20 also in blistering heat without any rehydration tablets or extra salt. It all depends on your fitness level, your body's capability of tolerating heat, walking speed and terrain. Naturally, sport nutrition companies want us to buy their teeth-damaging products, claiming that we need the energy and minerals to achieve our goals and I sometimes agree with them and sometimes not. I have been competing in marathon mountain biking for over 20 years and I use rehydration tablets or electrolyte sports drinks in competition, on very hot and long training sessions as well as on our annual week long training camp on Gran Canaria. For shorter training sessions and long ones in colder climate (below +20 C) I only drink water. Adding minerals and a little energy in the water bottle helps my recovery and I found that it worked just fine for me on GR20 last year in June-July. What works for me might not work for others, so everyone should reflect upon their own hydration experiences when it comes to trekking 10-15 days in very hot climate.

Stenning 45: No, I have not tried making my own tablets but I guess it should be relatively easy. I used re-hydration tablets bought in a pharmacy here in Sweden. The tablets are called Resorb and are described here (in Swedish): http://www.nestlenutrition.se/healthcare/se/products/Pages/Resorb_v%C3%A...

The nutritional facts are (per tablet in 120 ml water):
Energy = 15 kcal
Protein < 0.1 g
Carbohydrate = 3 g
Fat < 0.1 g
Sodium = 0.16 g = 7 mmol in 120 ml
Chloride = 0.2 g = 5.6 mmol
Potassium = 0.1 g = 2.6 mmol
Citrate = 0.7 g = 3.7 mmol
Osmolality = 290 mOsm/kg water

One side effect with these tablets is of course the Sorbitol, which can have a laxative effect, so do remember that one should always try new products BEFORE the trek so that one is sure that one's body and particularly one's stomach will not react in a bad way to the new product.

Good luck with the trekking!


Posted: Tue, Aug 21, 2012, 12:35

sure you can contact me, joanna at drange dot eu :-)


Posted: Tue, Aug 21, 2012, 16:41

Thanks very much DrGT, very interesting and thank you for the breakdown of what's in the tablets.

Regarding salt consumption, I have been sick twice from dehydration even though I was drinking plenty of water, I just sweat so much in the heat that all the electrolytes are simply flushed out. Lo-Salt, found in any super market, has potassium and sodium in it for restoring electrolytes. In Paris it was 39 degrees on Saturday and Sunday so I was adding it to my drinking water.


Posted: Tue, Jan 2, 2018, 22:01

How it is with water in winter. Do you know, which refugees are open, which is closed, which are used like a shelter? Thanks


Posted: Fri, Jan 5, 2018, 18:14

I have been on short stretches of the GR20 in winter and this is what it is like. The PNRC refuges are open, but they don't have guardians. You have to take your own food and look after yourself. Water inside the refuge is usually disconnected and the nearest source might be completely frozen. You might need to carry water. The gas stove is usually connected, but you might need to turn it on at the cylinder, and if the cylinder is empty, don't attempt to change it unless you know what you are doing. If there has been heavy snowfall, the refuge might be buried, and you will not get inside unless you can dig the snow away from the door. (I have seen a photo of the Refuge d'Usciolu where only a tiny part of the roof was able the snow. Private refuges are closed.