Pool Return Leak Repair
Leaking return lines are one of the most common pool leak points. Other than perhaps a hole in the vinyl liner itself or broken skimmers a leak in the return line of the pool happens often in older pools - and even new pools not constructed properly. There are a number of reasons as to why pool return lines develop leaks more commonly than other pool components.
The most common location to develop a leak in the pool return line is right at the pool wall where the return plumbing line connects to the wall fitting (vinyl and fiberglass pools) or where the pipe penetrates the shell (concrete)
The point at which the plumbing line connects to the pool wall is under leveraged pressure. The pool wall acts as a fixed point on one end of the pipe where the other end may migrate under shifting or settling soil conditions.
The proper way to relieve this leveraged pressure is to use a ninety degree fitting angled straight down the pool wall. By turning the pipe downward directly out of the pool wall you will eliminate the horizonal area of pipe exposed to settling soil.
The way that you repair a leak in your return line will depend on the plumbing material used when your pool was built. Most are black poly pipe which require rigid pipe fittings and clamps to make connections. The poly pipe with a red stripe is the correct pressure rated material.
Poly pipe with a white stripe is not suitable for pressure applications and should be removed and replaced completely. Poly pipe with no markings should be inspected closely and consider replacing with a more reliable flexible or rigid pipe that utilizes glued connections instead of clamps.
Newer pipe configurations use PVC pipe which can be flexible or rigid. Flexible pipe called tiger flex or spa flex is most commonly used in climates that experience freeze and thaw conditions. Rigid PVC should be schedule 40 at minimum to ensure it can withstand the crushing strength of settling soil over time.
Poly pipe connections should have two clamps attached to each connection point to ensure a reliable hold - especially in underground applications where a small leak could go undetected for an extensive period of time and potentially worsening the problem or damaging another area of your pool, house or yard.
Any poly pipe that is connected using nylon fittings should have all fittings replaced on the pool. This will usually require running all new plumbing lines also. Nylon fittings were used for a period of time between 1970 and 1995 mostly.
These fittings are reactive to chlorine and will most certainly fail if given enough time. The chlorine deteriorates the fitting which begins to wear away, almost liquifying it becomes so soft by the chemical reaction in some cases.
ABS pipe, which is rigid black pipe meant for non pressure rated systems is not suitable for swimming pool use however it is somewhat common to see this. ABS is more widely available than PVC from hardware stores in the sizes used for swimming pools. Avoid using ABS as this will fail prematurely if not right away.