Swimming Pool Plumbing Leak Repair

Pool plumbing leaks are one part of pool maintenance that makes many pool owners a little nervous, but making PVC plumbing repairs, or installing new or replacement equipment into the plumbing pipes is easy. PVC repair tools and materials are simple too, everything you need is at any hardware or home store. We also have some common PVC fittings in our pool plumbing parts department.

Making your own pool plumbing repairs can be a simple weekend project, keeping hundreds of dollars in your pocket!

Fixing Pool Leaks:

Pool leaks come in many forms, from the small drip to the large gusher. Most small drips won't amount to any noticeable water loss in the pool, and usually won't get any worse. But larger pool plumbing leaks can cause problems and need to be fixed, by replacing bad glue joints or cracked fittings - by cutting out the old and gluing in the new PVC pipe and fittings.

Suction Side Leaks

The suction side refers to all the plumbing before the pool pump impeller, which carries water under suction or vacuum. This is the skimmer and main drain suction pipes, fittings and valves, which terminate in the front of the pump. A leak on the suction side will draw air into the pipes when the pump is on, and leak water out (usually) when the pump is off. The most common suction side problem is a shrunken fitting, the threaded PVC fitting that screws into the front of the pump. So common that we've done a whole blog post on pool pump fitting repair. Suction side leaks can be patched with pool putty or silicone for a temporary repair, but will usually need to be cut out and replaced with new pipe or fittings - for best results.

Suction side valves can be cracked or damaged, or leaky - eventually needing replacement. But it can be difficult to just replace one valve on the suction side, oftentimes it's necessary to replace the entire suction manifold, or most of the pipes from the ground up, into the pump. It may be because all of the Tees and 90's are bumped against each other, or additional PVC fittings from previous pipe and fitting repairs can make future repairs impossible.

Pressure Side Leaks

After the impeller, the water flows under pressure, and any tiny crack or void will leak water when the pump is running, and often when the pump is off too. Pool equipment (pump, filter, heater, chlorinator) can all leak water from time to time, but today we are talking abou leaks on the plumbing or pipes and fittings that connect the pool and all of the pool equipment. The most common pool plumbing leaks on the pressure side are glue joints (where a pipe is glued to a fitting, like an MTA, 90°, 45° or coupling), or threaded joints, where PVC male and female connections are made.

Being under pressure, there is no way to patch an inground pool plumbing leak on the pressure side. You can't wrap it with leak-stopping tape, and pouring epoxy over the area won't work either. Wrap it a hundred times with duct tape and you will slow the leak, but it's still gonna leak! Suction side leaks can be patched with pool putty, or other sealants on the outside of the pipe, because the sealant is drawn into the crack under suction. But pressure side pool leak repairs cannot be patched effectively from the outside (or from the inside!), and need to be cut out and replaced.

Underground Leaks

Pool pipes that are underground are not usually the cause of pool leaks, but they can be broken from freeze damage, tree roots, settling decks or shifting soils. Flex pipe (Flexible PVC pipe) can be damaged by earwigs or chlorine, and is not recommended for underground use. Replacing underground flex PVC pipe with rigid PVC pipe is a common repair on 30 year old pools, so common that we've done a whole blog post on flex pipe skimmer repair.

If you are certain that the leak is underground, the next usual step is to pressure test the suspected line(s), and then listen with specialized equipment, to determine the exact location of the leak. Alternatively, if the length of pipe run is very short, or if the entire pipe is badly damaged, you can choose to replace the entire pipe and abandon the old pipe, leaving it in the ground.

For pools with a short pool deck apron (3-4 ft width), you may choose the option of tunneling under the deck, as opposed to cutting the deck and digging. In a few hours of digging, you can have the skimmer pipes completely unearthed, or dig up where a return line meets the pool wall. If you dig up enough dirt under the deck to expose the underside, use heavy timbers cut to size, to support the pool deck. If you only expose 1-2 feet of deck, you may not need supports.

Alternatively, the other option is to cut the pool deck with a concrete saw, bust up the deck, dig out the dirt and expose the leaking pipe or cracked pipe fitting. Either way, it's a lot of dirty work - but if you're up for it, read on.

How to Fix a Pool Leak

Once a pool leak has been located and identified, either above ground or underground, the next step is to cut out the bad and replace with new. Before you break out the hacksaw or reciprocating saw to cut the pipe, make a solid plan of attack. For complicated repairs, make a diagram to note all fittings and equipment. For simple fitting replacement you'll need enough room to be able to connect the new fitting to the pipe with a coupling. Make a solid plan of re-connection, before you start cutting the pipes.

When cutting the pipes, make a straight cut, and then clean up the cut edge with sandpaper or emory cloth. Remember to leave enough pipe to make a solid connection, about 2 inches.

Use PVC primer on pipe and fittings about 30 seconds before adding copious amounts of fresh PVC glue. Primer cleans and softens the pipe, heating up the plastic to make a solvent weld. Keep a rag handy to quickly wipe up any drips of glue after you push the pipe deep into the fitting and hold it for 10 seconds.

When gluing 90's and 45's, glue them in place with a length of PVC pipe inserted (dry fit, not glued) into the other side. This helps you to get the angle correct, for the exact direction that the fitting needs to face.

For threaded male PVC fittings, smear a silicone sealant like Blue RTV over the threads, and then wrap the threads several times with Teflon tape, in a clockwise direction (holding the threaded side of the fitting towards you). Tighten a threaded fitting in by hand, and then give it another 1 to 1-1/2 revolutions with large Channel-Lok® type pliers. 

Sacrifices:

In many cases, to replace a simple fitting, you may need to replace other fittings that are in the way of making a new connection. Sometimes a check valve, Jandy valve or union needs to be sacrificed, in order to replace a single leaking PVC fitting. Or you may need to reinstall the chlorinator or other pool equipment plumbing.

Jandy valves can be saved, if you spend time with a hacksaw blade and small screwdriver. When pipes are cut off right off against a valve, the glued pipe is still inside the valve port. Cut the inside pipe 2-3 times with a hacksaw blade (blade only), and then use a sharp flathead and small hammer to chip out the white PVC pipe, without gouging the valve. Another way to save a Jandy Valve is to go over the outside with a 2in coupling, then reduce the coupling back down to 1.5 inches with a reducer bushing.

The final connection that is made will be tight, and usually requires some bending of the pipes, or pushing of the equipment, to make the final glue joint connection. Pipes and equipment always have an inch or two of play in them, so don't be afraid to push and pull as needed, to make the final glue joint.

Other Pool Plumbing Repair Tips

• Don't reduce PVC pipe size with inserts or sleeves.
• Use as few fittings as possible, avoid pipe turns.
• Use Fresh medium or heavy body PVC glue.
• Water and Glue don't mix! Always glue Dry pipes and fittings.
• Use schedule 40, deep socket fittings, for pressure applications.
• For pool plumbing parts not found at a Hardware store, visit a Plumbing supplier.
• Don't use flex PVC pipe underground!