If you are the owner of a pool, at some point you have already noticed a drop in level in it. But often we wonder about the cause. Is this drop due to evaporation or a leak?

The different kinds of natural water loss in a basin

To begin, we must already begin by distinguishing between two types of natural water loss in a basin: evaporation and capillarity.

• Evaporation in dry or sunny weather : a significant amount of water evaporates and the pool can lose 1 cm of water in these cases,
• in dry and windy weather : evaporation can reach up to 2 cm of water per day. In certain cases of high summer heat, the loss of water can even reach 3 cm per day, especially in the basins which are home to many bank plants and fountains or waterfalls.

Indeed, the plants must compensate for the loss of water due to evaporation on the surface of the leaves and the splashes accelerate the evaporation process in the case of fountains and waterfalls. Another thing to consider, the larger your water mirror, the greater the evaporation will also be.

Capillarity.

These water losses can also be due to a physical phenomenon called “capillarity”, which should not be underestimated. Capillarity is the phenomenon of interactions that occurs at the interfaces between two immiscible liquids, between a liquid and air, between a liquid and a surface. It is due to surface tension forces between the different phases involved (Wikipedia).

To better visualize this definition, let's take the example of a blotter that will suck up ink or a sponge that will soak up water or even when you dip sugar in your coffee.

Thus, several things can be the cause of this capillarity: stones that deceive halfway into the water, pozzolana, the root system of plants or the folds of the tarpaulin at the edge of the basin. In these cases, the water rises between the wells and can be sucked up by the dry earth.

In conclusion, if you lose more than 2 cm of water per day in normal weather, it may be time to find a leak.

Find the leaks if it's not natural

If you have ruled out the two natural causes of water leaks, then the leak must be somewhere else and you need to find it.

So, to find the leak, here are some leads you can follow:

First, lower the water level until it stabilizes. Then mark that level on your tarp and add about 10cm of water above. We must now wait and ensure that the level stabilizes. Remove 10 cm of water from the marking, it will be in this area that you will look. Indeed, the leak zone can easily be identified by the color of the tarpaulin which will be the darkest.

How to fix the leak?