Pool PVC Plumbing Tips
Doing your own PVC pool Plumbing repairs is not difficult, and any handy homeowner can use a hacksaw and replace leaking fittings or valves.
Pool plumbing is usually either 1.5” PVC or 2” PVC, Schedule 40 pipe. PVC pipes are joined together with glued connections and connect to your pump, filter and heater with threaded connections. Read more about types of pool pipe.
Threaded PVC Connections
PVC fittings can be slip (smooth) or threaded. Male threaded fittings screw into the same size female fitting, hand tight, plus 1-1/4 turns with a small pipe wrench or large Channel-Lock type pliers.
Threaded pool PVC fittings are tapered, and overtightening can cause small stress cracks in the female fitting (or pump or valve ports), which can open up and leak quickly, or over a longer period of time.
To discourage overtightening, manufacturers like Spears and Lasco recommend the use of paste sealants like Permatex or Rectorseal pipe thread sealant. Silicone thread sealants can also be used, spreading into the male threads before screwing into the pipe. Use only sealants suitable for PVC, pipe dope and other petroleum based sealants for steel pipe threads can damage PVC materials.
Teflon Tape is not recommended by some manufacturers, due to the lubrication it provides, which makes it easier to overtighten the male fitting. However, the use of Teflon tape is very common, and in most cases makes a suitable thread sealant. Sealing properties can be improved by smearing a thin layer of Permatex #2 or other silicone thread sealant, before wrapping with Teflon tape.
To use Teflon tape on male threaded fittings, apply in a clockwise direction (as you are looking into the fitting from the threaded end), tightly wrapping around the threads 3 times, to build up a few layers of Teflon tape. Too many layers of Teflon tape, or previously applied layers of Teflon tape, can cause splitting of the female fitting or port.
Tighten a male PVC fitting only hand tight, plus 1 or 2 turns, and stop turning when you feel a moderate resistance. Pool pump ports are usually very strong, but filter multiport valves and female threaded couplings are easy to crack, when overtightening a male threaded adapter.
PVC Glue for Threaded Fittings? Thread sealants allow you to disconnect a threaded fitting in the future, but you can glue threaded PVC fittings together, using a Primer and PVC cement. However, avoid overtightening, and don’t glue threaded fittings into your pool pump, filter or heater, which can be impossible to remove, if a leak should develop.
Glued PVC Connections
Pool filter systems are 'pressure fittings', which are deeper than 'drain fittings'. Pool PVC fittings allow you to glue the pipe to a depth in 1-1/4", over twice the depth of DWV (Drain, Waste, Vent) fittings. Be sure to use only the deeper socket pressure fittings when plumbing pool systems.
Cutting PVC Pipe: Numerous saw types can be used to cut PVC pipe. Hacksaws, cable saws, or reciprocating saws can all be used. For best results, make a straight cut across the pipe, and use Emory cloth or sandpaper to remove rough edges and burrs from the pipe before gluing.
Measuring: Use a rigid tape measure to double check distance between fittings, including the full depth of each fitting. There often is enough space to accommodate pipes that are cut too long, but a pipe that is cut too short will not glue fully and can blow out under pressure.
Dry Fitting: Connecting all of the pipes and fittings together first try, or without glue, is difficult and perhaps unnecessary. But you should plan your sequence of glue joints, and continuously re-verify distancd and angle as you work. Try to end with a single glue joint where the pipes have come flexibility, to bring it all together tight and straight.
PVC Glue: For pressure applications like pools and spas, use a medium or heavy body (thick) PVC glue. Color of the glue does not matter, the most important thing is that you use fresh PVC glue, and not something that is out of date, or exposed to air from a loose cap.
PVC primer and cleaner are two different solvents used just prior to making a glue connection. PVC cleaner removes grease, dirt and PVC coatings, to create a better bond. PVC primer also cleans the pipe, but the stronger solvent also softens the PVC pipe, creating heat which helps to fuse the pipe and fitting together for a better bond and seal.
Purple Primer is a popular type of PVC primer/cleaner that is required by many inspectors, because it stains the pipe, making it easy to see that a primer was used, for a true solvent welded joint. Clear PVC primer can be used on pool plumbing repairs that are not being inspected.
For best results when using primer or cleaner, apply PVC glue while the primer is still wet and the pipe still tacky. Prime both male and female surfaces, and within 5-10 seconds, add a liberal amount of PVC glue with the dauber, and join together pipe and fitting with a twisting motion.
Tips on Pool Plumbing Leak Repairs
- Water leaks cannot be fixed by applying glue, epoxy, silicone or tapes. Leaks on the pressure side (after the pump), must have the leaking fitting(s) replaced.
- Air leaks, on the suction side of the pump, can be temporarily sealed with epoxy or silicone, applied while the pump is running, to suck the sealant into the void.
- Painted pipes should be cleaned or sanded before gluing. Do not glue painted PVC pipes.
- Glue joints cannot be made underwater, or with wet PVC surfaces.
- Compression Couplings can be used for wet, dirty or rough pipe surfaces.
- Unions allow access for service or removal of equipment, and can be resealed if needed.
- Pipe Extenders can be used in tight spots, to avoid replacing excess fittings or valves.
- Don’t use Flex PVC or DWV pipe, use rigid schedule 40 PVC pipe.
- When joining steel and PVC, always connect male PVC to female steel, to prevent cracks.
- Pumps and heaters can overheat and shrink PVC threads; use CPVC for high temps.
- Use only Fresh PVC glue, medium or heavy body, applied directly after a primer.
- Allow PVC glue 30-60 minutes to set-up before re-starting the pool pump.