How much water should I lose in a week in an inground pool?

Question

In the last 2 weeks, I lost about 4'' of water in my 18x36 inground pool with the solar cover on? Is this normal or do I have a leak?

Answer 1

It's a bit much. I'd expect half that volume in a two week period as a rule, discounting back washes for a sand filter. It's still possible that it's evaporation though. One easy way to find out is what's called the bucket test. Place a heavy, round object ( no sharp edges) in a plastic pail. Put that pail on one of your pool steps that's submerged. Add pool water to that pail until the level of the water in the bucket is the same as the level of your pool water when viewed from the side. Leave it for 24 hours.

When you check it next day, if the level of the pool is below that of the bucket, yup, your pool has a leak. If it's the same level, there's no leak and the water loss was likely evaporation. Don't worry if it rains. The bucket will fill at the same rate as the pool, so won't throw the result off. It also evaporates at the same rate, which is the beauty of this test in finding out if you have a leak or it's evaporation.