Threaded vs. slip connections for plumbing


LifeTime Supporter
May 31, 2008
North Virginia
Hey All:

Any pros/cons, thoughts comparing threaded connections vs. slip connections for equipment plumbing?

Threaded adds another place for leaks, but (with a union) allows for replacement without cutting. But, is the replacement aspect worth the risk of an extra leak place?

Be well.




Well-known member
Jan 20, 2008
Northeast Florida
I had three expensive valves ($40 each) and I used threaded connections near them so they could be replaced easily. I used slip everywhere else, because elbows and pipe are cheap. Some people will tell you to use lots of teflon tape, but the manufacturers caution against using too much because it can cause the female fittings to crack. I used a combination of several turns of heavy duty teflon tape and some pipe sealant. the most important thing to remember with teflon tape is that you can't back up after you tighten or you will have leaks for sure.


TFP Expert
LifeTime Supporter
Apr 4, 2009
I prefer slip connection with unions. If you decide to use threaded connection, use oately/great ptfe white pipe dope. Tape tend to do poorly on 1.5" and larger PVC fittings.


Platinum Supporter
May 4, 2010
SW Georgia
The only fitting on my pool plumbing that leaks is a threaded fitting. I was told that the cutting of the threads makes the PVC thinner and thus more subseptable to breaking. I actually witnessed this on my pool as the threaded return broke due to the pressure of the backfill. It broke at the threads. I am 100% for slip fittings unless threaded fittings make life easier when you have a problem. When my return fitting broke I was glad it was threaded because of the limited work area I had to fix it. Had it been a slip fitting the fix would not have been as easy. To sum it up I use slip fittings unless threaded fittings could make repairs easier.


Well-known member
Aug 1, 2010
I use PTFE STRING on the threads. We have lots of brands of it here in Europe (Loctite for example as well as Tangit) and it's much better than PTFE tape as you can back it off and don't have to be so careful applying. I supplement it by using a type of non setting sealent that used to be used for hemp thread sealing. I only use threaded fittings going into expensive parts though, like filter valves, pumps, swg's etc. The rest slip all the way.


LifeTime Supporter
May 31, 2008
North Virginia

Some great thoughts :-D
(smileys not working)

I like the flexibility: do it when it would make repairs easier. That's my situation....previous owners left no room for repairs.

I also experienced cracking at a threaded fitting.

Thanks again!!!

Thread starter Other Threads of Interest Forum Replies Date
A Pumps, Filters, and Plumbing 6
S Under Construction 12

Other Threads of Interest