Why does my sewer line clean-out keep popping off even though screwed on tightly?

Question

It keeps happening and sewage will come out of the clean out though the clean-out. I've screwed it on tightly and it keeps happening. There is no sewage back-up in the house. All of the toilets flush fine.

Answer 1

Im a Plumber of 20yrs and there could be a few things.

It sounds like you have a back flow preventer in the house

what this does is allow water to escape out but not back in.

But also for sewage to come back up through the C/O that means it is not getting to the main line in the street

What is happing you are creating pressure in the line and popping the cap off.

(I wish you would add more to your question like)

when the cap comes off does the water go down

is it septic system

is the C/O in the house or outside

do you have a basement

are there tree's in your front yard where the main line is

what is the cap made of ie Plastic ect

Have you ever had the line run

With all this I could help out alot more or e-mail me at

[e-mail]

But something is not correct here If i was to come to your house I would run the Main line with a snake and ck the system. If it keep doing it the I would Cam the line to see whats going on.

See your saying the cap pops off but do you mean it comes off then now sewage is just going into your yard but you your WC's (toilet) work fine.

Either add the details to your ? or e-mail me and I will help you solve your lil problem

Goodluck

Answer 2

There's a sealant used, like teflon, to make sure it's sealed properly. Not exactly sure what they use now, but a plumbing supply house would know.