The biggest factors affecting this are humidity, wind, and air and water temperature. In the Houston area, we can expect more evaporation because of our warm weather.
Determine the Rate of Water LossTo find out if you do have a leak in your swimming pool, fill a bucket with water from the pool and set it on the steps of your pool with the top of the bucket above water level. If you have a lader, balance the bucket on the top ladder tread. Compare the water loss between the bucket and your pool over a period of several days.
Find the LeakIs the leak in the plumbing / filter system?
Fill the pool to its normal level and mark it with a piece of duct tape. Turn on your filter system and keep it running for 12 to 24 hours. Measure the loss of water.
Refill the pool back to the same level and with the filter system off, wait the same amount of time and measure the water loss.
If you are losing more water with the filter system running, the leak is on the pressure side of your plumbing somewhere AFTER the impeller of the pump. If you are losing less water with the filter system not running, the leak is on the vacuum side of your plumbing somewhere BEFORE the impeller of the pump.
If the water loss is the same, then your leak is in the structure of the pool and not in the plumbing.
Leaks in the plumbing
Check the outflow in your backwash line? There are two ways to find this leak. First, you can pressure test the lines, then dig, following the leaking line till you find it. You can also call in your local leak detection service. We would highly recommend the latter, unless you like to dig. Professionals will use "geophones" to listen for the leak and only dig where necessary!
Leaks in the pool structure
What if you have a vinyl pool with a leak? We recommend you first check around all the items that pierce the liner:
- main drain,
- lights, etc.
If leak is not around the fittings, you will need to search the liner. Running your hand over the floor and walls you may feel a tear or puncture that's not easily visible. After finding the leak it is an easy matter to patch, using a vinyl patch kit and following the directions.