Can I Use a Wet Plumbing Compression Fitting?

Wet Fittings

• Compression fittings can be made of both metal and plastic. A mechanism, either a clamp that is squeezed over the connector or a nut that applies torque to the fitting, binds the fitting and creates the seal. This seal is created through force and pressure, which means that small amounts of moisture will not affect the connection. But it is still a good idea to dry all parts as much as possible before using the fitting to create a better seal and avoid slippage.

Compounds

• In some cases, thread compound or a similar type of plumbing compound can help you prepare the piping for the connection. This thread compound lines the inside of the fitting and basically helps form a more permanent seal that keeps leaks from developing later on in the life of the plumbing. For this compound to work well, it should be applied to a dry pipe and dry fitting so it can adhere more easily.

Leaks and Adjustments

• Sometimes when screwing or clamping on a compression fitting, water will still leak over the fitting as you adjust and tighten it. As long as you are still working on the compression, you rarely need to worry about this extra water. Stopping and reapplying the fitting would only take you back a step. A properly installed compression fitting should fully stop this leak by the time you are done. If the pipe still leaks, you can take the fitting off and readjust it afterward.

Tightening

• Compression fittings were meant to be tightened, but that doesn't mean you should tighten them with as much force as you can muster. Tightening a wet compression fitting will not make the compression process work better or make up for the moisture. But it might break the compression ring or violate the seal you have created. Tightening too much may even damage the pipe beneath the fitting, so do not use extra force to make up for a wet fitting. Install the fitting normally, making any necessary adjustments as you work.