The pool is a closed water system and not connected to the home water supply Unless you have an auto fill). If the pool is suspected to be leaking, a dedicated pool leak detection is required. The first thing you should do (if you are a DIY person) is perform a bucket test to inspect if you really have a leak, or your pool is losing water due to normal evaporation.
- Fill ¾ of a 5-gallon bucket (home depot bucket) with water and place it on the pool step.
- Mark the water level of the water in the bucket with tape and the then mark the outside level.
- Check water level with a ruler after 24 hours of normal pool operation.
- If water level inside and outside the bucket dropped at the same rate, then the water loss is just evaporation.
- If there was a greater water loss on the marking outside the bucket, suspect a leak in the pool.
Before performing a bucket-test make sure the pool auto fill is OFF (not all pools have an auto fill), otherwise you will not get accurate results because the pool will keep on filling with water.
Generally, pool leaks are divided into three categories:
Structural leaks: Any leak that causes loss of water through a crack in the structure. These cracks can also be hidden behind the light fixture, around the skimmer etc.
Suction side leaks: Considered to be a leak in the plumbing system that is pumped from the pool to cycle through the filter.
Return side leaks: Considered to be a leak in the plumbing lines that return the water from the filter / heater to the pool.
If you suspect a leak in the pool after the bucket test, look for a professional pool leak detection inspection.