We've moved to a bigger location! Locate Us

Fun in the Sun.

January 11, 2017

How to: DIY Leak Detection for In-Ground Pools

Here is a list of possible places you might be losing water. Remember, 1/4″ per day is normal for evaporation. More evaporation is normal if it is excessively hot or your pool has heavy bather loads. BioGuard’s Smart Shield will help with normal evaporation.

Bucket Test

Evaporation is dependent on a variety of environmental and pool related conditions, (wind, water temp, dew point, barometric pressure, etc). Because of this, the evaporation rate can vary greatly from day to day and even pool to pool. Before becoming too concerned about a leak you can do this simple swimming pool leak test to determine if water loss in your swimming pool is due to a leak or is just evaporation. This simple test is called the bucket test. Basically, the bucket test exposes water in a bucket to the same conditions as those affecting your swimming pool. By comparing the water loss in each, it is possible to determine if the pool is leaking or if supposed leaks are just the result of evaporation.

  1. Bring the pool water to its normal level
  2. Fill 5 gallon bucket with pool water to about one inch from the top of bucket. (By filling the bucket close to the top you are ensuring that air movement over the surface of the bucket will similar to that of the pool.)
  3. Place the bucket on the first or second step of the pool. (By placing the bucket in the pool water you are ensuring that the water temperature of each will be similar).
  4. Mark the water level inside the bucket.
  5. Mark the water level of the pool on the outside of the bucket.
  6. Allow the pool to run like normal.
  7. After 24 hours, compare the two levels. The inside loss is evaporation. The outside loss is evaporation plus any leaking.
  8. For even better results, run the bucket test with the pump off for 24 hours and see if that changes the results.
  9. Losing more than 1/4″ a day? Contact us for a Leak Detection!

Possible Causes

Hole in Liner:

Clean the pool and do a visual check of the entire liner. Usually a hole in the liner appears to be a leaf or piece of debris until examined closer. The pH liquid test kit reagent works well if you take it underwater near the suspected hole, squirt a little of the reagent and see if it immediately sucks back into the area. This would indicate water is being leaked in this area. We have inexpensive vinyl liner repair kits that work well underwater. If you don’t find the leak with a visual check, but are sure a hole in the liner, our service department has an electronic device that will find virtually any underwater hole in a liner.

Inlet Return Lines or Auto Cleaner Pressure Line:

These lines are best tested by plugging off and pressurizing them with a pressure gauge system to see if they hold pressure. Typically, if you have a leak in a pressure line, much more water is lost with the pump running than when the pump is off. If you are certain the leak is under the ground or decking we recommend a dedicated leak detection company who can pinpoint the leak for you.

Hydrostat in Main Drain Fitting: 

This fitting is located under the main drain cover plate. A new hydrostat fitting replacement is inexpensive, but requires a ton of time underwater. If you need help, our service department can do this for you!

Faceplates around Skimmer and Inlet Fittings:

These can be tightened with a heavy duty philips screwdriver if needed. If the water level drops just below the skimmer or other fitting and you have already tightened the faceplate, it may need to be removed so you can replace the gaskets.

Conduit behind Pool Light:

Occasionally the light cord conduit cracks and you will lose out the conduit. Our service department can repair this type of leak by draining the pool below the light fixture and removing the fixture to silicone the conduit.

Bad Filter Valve Spider Gasket:

This will cause water to leak out of the backwash hose or pipe. A visual check can usually determine if you are having this problem. It is a little harder if your backwash line is buried, but you can typically see water through the sight glass of the valve. This can be repaired by replacing the spider gasket and using Magic Lube. If this problems persists, the top portion of the valve should be replaced as well.

Crack in Skimmer Housing:

This leak can be found with a visual check and can be repaired with an epoxy product like Pool Putty.

Pump Shaft Seal:

If the pump leaks water between the pump basket housing and the motor, you probably have a bad shaft seal. This is usually a minor leak, but over time the chlorinated water will cause corrosion of the motor. Shaft seals are inexpensive but are difficult to install.

Note: Every time you separate shaft seals, they always need replaced. Never touch the ceramic (white) area of a shaft seal. This will cause it to never seal correctly. 

Main Drain Liner, Skimmer Line or Other Suction Line:

Test by running the pump with only the line you are testing open. If the pump cannot run without air bubbles, there may be a problem with this line. If pump is hard to prime anyway, another test if to get the pump running as you normally do, gradually open each line you are testing and then gradually closing off all other suction lines. It often helps to label each line with a permanent marker. Also check the PVC fittings and ball valves before the pump for air leaks.

Losing more than 1/4″ a day?

Contact us to schedule a vinyl liner leak detection!