As summer starts to give way to fall and nighttime temperatures begin to drop, swimming pool companies begin to see an uptick in phone calls and emails from customers who think their pool may have a leak. They observe their water level dropping noticeably from one day to the next, and are convinced that a crack or hole must be letting water escape. While that may be true in some cases, more often there is a different mechanism at work: evaporation.
The Bucket Test: An Easy Way to Check for Pool Leakage
Your local dealer has equipment that can be used to detect leakage and isolate the source. They also have a device that can be used to measure the rate of evaporation. However, there is a simple and reliable test that you can conduct yourself to help determine if water loss is due to a leak or evaporation. Here’s how it works:
- Get a bucket.
- Secure it to a step in your pool. A heavy rock in the bottom of the bucket is often all you need.
- Fill the bucket with water up to the same level as the pool water. Use tape or waterproof pen to mark the water level in the bucket.
- Leave the bucket in place overnight.
- Check the bucket water level in the morning.
If the pool water level has dropped but the bucket level has not, it’s very possible that you have a leak. If both have dropped at the same rate, the cause is almost certainly evaporation.
The differential that occurs between the pool water temperature and the air temperature on late summer nights causes water to evaporate at an accelerated rate. In some cases you might see a water level difference of 1-3 inches overnight. Depending on the size of your pool, that can be over 500 gallons of water loss!
Why Water Loss Matters
Excessive overnight water loss is an issue for many reasons:
- It costs money to replace the lost water.
- The change in volume can affect water chemistry, causing calcium scaling and other issues.
- Water loss and heat loss go hand-in-hand, and it is expensive to keep bringing your pool up to the desired temperature each morning.
Needless to say, you want to control evaporative water loss as best you can.
How to Prevent Overnight Pool Water Loss
Fortunately, there are a number of ways to curtail overnight evaporation and keep your pool water where it belongs. One is to put a solar cover in place every night. While this is effective, it does require some manual labor at the end of each day.
Another is to use a “liquid pool cover.” This is a chemical you add to your water that forms an invisible barrier on the surface that cuts down on evaporation. You won’t notice this substance while you are swimming, but as soon you’ve left the pool and the water settles, the barrier reforms. Again, this approach can be effective, but the chemical is slowly broken down and must be replaced monthly.
Perhaps the best solution is to install an automatic safety cover. Not only can you deploy it each night with the flip of a switch and prevent costly water and heat loss, it also keeps your family safe by preventing children and pets from entering the pool without supervision.
Let’s Address Your Water Loss Concerns
If your bucket test is inconclusive or you’d simply like to get a professional opinion on your water loss, we’re happy to help. Contact us if you are in the Chicago area or find the local independent Latham dealer near you today and let’s be sure you’re avoiding unnecessary costs from leaks or evaporation.
Editor’s Note: Updated 6/2021