As a heavy sweater I know how bad it feels to run dehydrated. Losing more than 2% of your body weight in fluids can negatively affect endurance and other aspects of physical performance. In temperatures above 25 degrees Celsius I loose as much as 1.5 liter of water every hour. That means that even with a running vest, I can’t run hours on end without refilling my flasks. But where can you find drinking water on the trails?

I have applied many solutions to this water issue, whenever possible:

1. Run in loops (or out-and-back). Keep returning to your car (or bike) every hour. It acts like an aid station. This can be quite boring but sometimes the only choice.
2. Look for supermarkets or gas-stations near the route
3. Visit mountain huts or other type of restaurants
4. Bring your water filter and find creeks or other natural water sources near the route
5. Run supported
6. Join a race which will have aid stations. But even then, with my pace, time between aid stations can easily be more than two hours.
7. Finally, there are water fountains along the course. How to find these by creating your own water map will be the topic of this article

For my upcoming race in the Swiss Alps, I will make good use of these. This will be especially helpful in case of a warm or hot day. They are very welcome next to the six aid stations on my course. For cooling, but also for drinking. Fortunately there are a lot of these water fountains in Switzerland, with good quality drinking water. Every (small) village will have one and you will find them outside of the villages as well.

In OpenStreetMap, these are added as elements which are tagged with amenity=”drinking water”.

So the data is there, but not every OSM map viewer shows those details. And if they do, only from a certain zoom level. The way I used to search for drinking water is to load the gpx file of the course into: http://www.mygpsfiles.com/app/, zoom in at least to 50m, follow the route and look for water symbols. This manual search works, but there is a better method:

You can create your own map with your course loaded and water points marked automatically, using the uMap website. You create a three-layer map. The first layer is the OSM map itself. The second layer is the gpx file. The third layer shows the drinking water points.

Step 1 : https://umap.openstreetmap.de/

Step 2 : Load data – Load the gpx file of your course into a new layer

Step 3 : Add a third layer of type “remote data”, using the following URL and output format osm.

https://overpass-api.de/api/interpreter?data=[out:json][timeout:25];(node["amenity"="drinking_water"]({south},{west},{north},{east});way["amenity"="drinking_water"]({south},{west},{north},{east});relation["amenity"="drinking_water"]({south},{west},{north},{east}););out body;>;out skel qt;

And turn Dynamic to ON

Optionally you can set a color and icon for your water points using uMap’s shape properties.

And your map is ready. You can give it a name, save it and share it with friends.

You can also quickly scan an area for water points using this ready-made map: https://umap.openstreetmap.de/de/map/trinkwasser-auffullen_256#14/51.1083/13.6128

And what about my race? I have found 11 drinking fountains on the course, so plenty of refill opportunities. Even running this course outside of race day (unsupported) should not be an issue, even on hot days.