There are a lot of questions about swimming pools and water loss. How do you know when you have a leak, and how can you recognize normal evaporation?
How do I know if my swimming pool is leaking?
Swimming pool water levels do fluctuate. You might fill the pool, run the heater, and see evaporation speed up during cold summer nights. Occasionally the backwash hose on a filter will be the culprit, sometimes it’s splashing, and others you may actually have a leak in the pool through a structural crack, or tiny hole in the liner. Even a hole in the liner the size of a pin-hole can drain your entire pool given enough time. Let’s explore some of the common causes and concerns for pool water loss.
Pool leak symptoms resulting from water loss
The most common indication that you have a leak is when the water level drops faster than can be attributed to evaporation or splashing, and less than .25″ a day is normal for evaporation, unless you are heating the pool and your nights are cold.
How do you know what is normal evaporation? When leaks are slower and smaller it’s harder to determine the exact cause.
To perform the bucket test:
- Take a 5-gallon bucket and make a mark with a permanent marker at about the halfway point. Fill the bucket with (pool water so it’s the same temperature) water up to that point, and set the bucket right beside your swimming pool. Simultaneously, use a pencil to mark the water level on your pool tile. In that way, your can determine how much water has evaporated from the bucket and from the pool. **If you are running your heater continually during this process, and your air temperature is causing steam to billow off your pool this will not be an accurate way to measure your evaporation.
Automatic Water Fill
If you have an automatic fill device on your pool you may not notice the fluctuating water level; high water bills may be the first indication of a leak problem. You may also notice an increase in the chemicals required to maintain proper balance.
Other symptoms of pool leaks might be wet areas around your equipment pad, or visible dripping at any of the equipment. Wet, extra green, or soft spots in the lawn may be indicators of a leak. Cracks, or anything that doesn’t look normal in the actual surface of the pool could also be an indicator.
Air in the pump or blown into the pool
If you are getting air in your pump on the suction side that is a common indicator that you could have a leak in your suction side lines on your pool such as the skimmer and main drain. It could also indicate a plug isn’t tightened quite right at the equipment pad itself, or your pump lid might not be aligned just right.
Checklist when you think you have a leak:
- Visually inspect the pool and equipment. Is anything dripping where’s not supposed to?
- Double check your backwash line. When the filter is in normal filter mode do you have any water leaking down the backwash hose as a result of an out of place gasket in the multiport?
- Can you see any structural cracks or areas that look suspicions in the pool?
- If you have a vinyl liner pool, what is the age of the liner, and do you notice any small holes, tears, or bubbling behind the liner?
- Is your pool losing the same amount of water while the pump is running as it is when it is turned off? To check this turn off your pool. Mark the water level with tape or a sharpie marker. Wait 24 hours. Note the new water level. Resume normal pump operation. Wait 24 hours. Did the pool lose more water/less water/the same amount of water? If it loses the same amount of water while on or off, look to the pool itself as the source of the leak. If it loses significantly more water while running the pump, and you don’t have any issues with the pump priming you will want to look at the return lines as the potential culprit – and it’s time to call in a professional to pressure test your lines.
- Do you have a pool light? A leak in the light niche in older pools is sometimes common.
- If you let the leak continue until it stops where will it stop leaking? *Don’t allow the water level to get too far down in any pool – this can cause serious issues. In a vinyl liner pool, the liner can float/or wrinkle resulting in the need for a whole new liner vs. just a patch. A gunite pool or fiberglass pool can experience ground water pressure that could cause structural damage to the pool.
- If you suspect your skimmer, light or returns you may want to close your skimmer and let the pool leak out until it stops. The level where the leak stops will show you what areas you can focus on to find the leak. In older gunite pools cracking in the skimmer is a very common place to notice a leak. If the leak stops at the level of the returns in a liner pool, check the screws and areas around the return. Check the gastkets/screws on the steps at this level, and finally check around the perimeter of the pool to see if you can find a hole. A hole, even the size of a pin-hole can cause your pool to drain. Finally, check the water level if the leaks stops in the middle of the light. You may need to pull the light out of the niche, putty the conduit, and add a little water to see if it holds the water or if it drains back down to the same level.
If you do test your pool for leaking, make sure to add chlorine before, during, and after, especially if you have your system off for any length of time so you keep your water as clear as possible so you can SEE into the pool to help diagnose your issue. A dye tester may be helpful if you discover structural cracks or suspicious areas on a vinyl liner pool.
If you start to troubleshoot on your own keep very specific notes about the water level, what you did to check for the leak, and what you find. It will help your pool professional to go through all of the questions with you to save time and money in establishing the source of the leak!
A few helpful products that will help you once you find your leak are:
- vinyl liner patches and repair kits
- pool putty – for those skimmer cracks and pool light niche fixes
- Mr. Sticky underwater glue – a fixer for all sorts of things
- Butyl Tape for Conduit repairs
Pressure Testing by a pool professional