Rubber Couplers

• Rubber couplers are used to join PVC with non-PVC piping, such as steel, iron and copper. If the coupler is leaking, tightening down the hose clamps on either side of the coupler may solve your problem. Over time, however, rubber couplers can dry out and allow for gaps and leaks. A dried out or stretched coupler will need to be replaced.
  
  

Replacing Rubber Couplers

• A rubber coupler joining PVC and copper pipes can be easily replaced. Purchase a matching coupler from any home improvement or plumbing supply store, and remove the existing coupler. Once the two hose clamps are loosened, the old coupler should slide off the PVC and copper pipes with some effort. Install the new coupler and ensure you push both the PVC and copper pipes as far in to the coupler as you can before tightening down the hose clamps.
  
  

Threaded Fittings

• Threaded PVC-to-copper fittings consist of a male end, which is either soldered to the copper pipe or cemented to the PVC pipe, and a female end which is on the opposite material. These fittings may leak if the male and female threads do not line up perfectly. A short term fix is to unscrew the male end, and cover the threads in plumber's tape. Reassemble the couplers and check for leaks.
  
  

Replacing Threaded Fittings

• Threaded fittings are not as easy to replace as rubber couplers. The pipes they are tied to will need to be cut in order to install new fittings and additional pipe may need to be added to either the PVC or copper line to ensure they reach each other. Solder the copper end to the copper line, and PVC cement the PVC fitting to the PVC pipe. If the two fittings do not reach, it may be easiest to cut the PVC line and install a small extension, which can be purchased at any home improvement store.