Pool Care /
Why Is My Pool Losing Water?
A pool can lose water from evaporation, splash-out, backwashing, or a leak. Check the water level, equipment, and surroundings in a safe sequence first.
Archive date: this article was written for PoolSkimmer on Oct 23, 2026 and given the earlier archive date of Jun 29, 2026 so the blog reads as an organized archive. It was not published on that date.
The question of why the pool is losing water
It is not unusual for a pool to shed some water through evaporation, splash-out or routine maintenance. Yet when there is a steady decline in the level, it is often a sign that water is making its way out somewhere. One has to determine if the loss is in line with the weather and how much the pool is being used, or if it persists even with the pump off and the water undisturbed. Any unexplained or rapid drop should be viewed as a potential leak.
What is behind the water loss?
There are several culprits that do not call for any repairs:
- Evaporation: A hot, dry or windy day will take more from the pool than normal.
- Splash-out: Diving, swimming and active water features have a way of pushing water over the edge.
- Service work: Backwashing and other maintenance will put the level down.
- Circulation: Restricted flow or a clogged skimmer basket can mask an issue and give the impression of quicker water loss.
If the water seems to go missing only after a particular activity, it is more likely use or maintenance at fault rather than a structural one.
A safe way to check for a leak
Proceed with a methodical approach.
1. Put a mark on the water level and come back in a day or two, provided there has been no backwashing or swimming, to see where it stands. 2. Factor in the conditions; heavy swimming brings splash-out and wind will up the evaporation rate. 3. Examine the skimmer and pump. Make sure the pump is shut off before you open up the skimmer basket. 4. Walk the equipment pad. Give the pump, filter, heater, valves and the ground around them a once-over for any drips or wetness. 5. Note the pattern. Should the water fall faster with the pump in operation, look to the plumbing or equipment. If it happens with the pump off as well, the liner, shell or underground lines could be the source.
Some will run a bucket test to tell evaporation apart from a leak. But if you are in any doubt as to how to do it safely, or your equipment manual advises against it, leave it to a professional.
Signs of a leak
You may find certain indicators that point to a leak:
- Standing water or damp earth by the pool or equipment
- Poor circulation or air in the pump basket
- Cracks or loose fittings about the return lines
- Water loss that ceases at a given depth
None of these alone confirm the exact failure, but they will help you zero in on where the water is going.
Pitfalls to avoid
Diagnosis can be made difficult by a few common errors. Do not check the skimmer basket with the pump running. It is also easy to overlook the effects of recent backwashing or a spa overflow, or to jump to the conclusion that every bit of water lost is a major problem. And if the level is in a steady decline, do not put off an inspection.
Time to get a professional involved
If the water is vanishing quickly for no apparent reason, or you suspect damage to the structure or underground plumbing, make the call to a qualified pool pro. They are best suited for pressure testing, leak detection and any electrical or heater issues.
Above all, if you have reason to think there is an electrical fault or the water is otherwise unsafe, stay out of the pool. Stick to the guidelines in your manuals and chemical labels, and wear the proper PPE when you are doing maintenance.
Sources and further reading
- [Hayward: Weekly pool maintenance](https://www.hayward.com/maintenance/weekly-pool-maintenance)