Leak Test Condition 4

Leak condition 4 refers to the pool leaking when the plumbing system is on, and not leaking when the plumbing system is off

pool pump

Pool Leaks When Pump Is On

The leaking condition where the pool leaks when the pump is running but seems to hold water well enough if your turn off the pump off is either going to be related to a problem with your filter, or more likely a leak in one or more of the return lines going to the pool.

Symptoms Of Return Line Leaks

One of the most tell tale sign of a long term return line leak is to see sinking, cracking or uneven ground surfaces and especially right overtop of where each return fitting meets the pool wall.

Often times you will see that one or more of the return lines in your pool has been repaired at the pool wall evidenced by a patched area over the return fittings. If there are any returns that have not been dug up previously this would be highly suspect if one or more have been repaired. Service professionals often prefer to repair all return fittings if one is found to be faulty given the high likelihood for failure of the others. If you already have the tools on site to dig up one return line then it is more efficient to do the others also.

Likely Leak Locations

Based upon the leak characteristics displayed by your swimming pool during the hydrostatic leak test, here is a list of the more likely areas of concern for your pool. This information is not sufficient for stand alone diagnosis of your swimming pool leak in most cases, but can very often lead to an efficient diagnosis and repair due to recurring instances of these common pool failures:

(small leak of less than 1” / 2.5cm per day)
-Small crack or loose fitting on return line
-Leak in the pump, filter or heater
-Filter head gasket out of alignment

(medium leak of 1-3” / 2.5-7.5cm per day)
-Broken return line
-Filter head gasket out of alignment

(large leak of more than 3” / 7.5cm per day)
-Multiple return line leaks
-Filter head gasket out of alignment
-Broken fitting or pipe in return line

If you suspect that you have one of the leaks here, or you have a pool leak that meets condition 4 of the hydrostatic leak test then you should read what industry experts say about a pool leaking when pump is running or you can choose to proceed to the next leak test which is the water level leak test

The menu on the right is a chronological step by step process to determine where a swimming pool is leaking. This website is written as a readthrough technical assistance guide for locating leaks. When you believe you have identified where the pool is leaking you need to go to our sister website to see pictures and learn more about the actual swimming pool leak repair process.