Good Morning! Our toilets have not been flushing properly the last 2 days~ the bowl fills with water and it takes hours for it to recede on it's own. We now discovered there is a back up out side at our sewer line cap. The cap however was off! It's one that you screw on (has threads and made of PVC)~ my husband put the cap back on and now the toilets both flush properly. Could that cap blow off (even if it's the screw on kind) and cause the back up or did him putting the cap on fix the issue? We do have a plumber coming this afternoon... but made the appt before we discovered the cap off. Please advise. Thank you for your time and help!

You had a blockage in the drain line of the toilet that was backing up.
The cap out side is the cap for a clean out. A clean out is a place in the main sewer line which you can open up to snake the line. A blocked sewer line will not blow a cap off.

The blockage in the sewer line must have been before the clean out or the sewage would have come out the uncapped clean out.

For reasons unknown the blockage has opened up. Cancel the call for the plumber. You don't need him and he won't be able to help you since the blockage has cleared itself. It may return if there is something still caught in the drain for the toilet. If it does you and call for the plumber again.

You have the luck that everyone else hopes for.

Thank you so much!! The mystery still remains~ how did that cap come off for the sewage to flow outside?

Have one that most repair plumbers miss.. Look down at the bottom of the bowl. If there is a small hole, then that is a jet that starts the syphon action. If it's clogged the water will just swirl around and slowly go down leaving solids behind. Take your finger,(UGH! ) and run it around the inside of the opening. Over the years minerals build up and cut down on the syphon (flush) action. If it is rough or you feel build up, take a table knife and put a bend in it to get around the curve in the bowl and chip and scrap it clear. Next take a coathanger and clear out the holes around the rim. They start the swirling action. And last, check the water level in the tank. It should be 1/2" below the top of the over flow tube. And speaking of the overflow tube, Make sure the small 1/8" tube from the ballcock to the white overflow tube is connected so it discharges in it and that it's flowing when the ballcock fills. This is what raises the water level in the bowl. For a good solid flush they all have to work together. Hope this helps. Good luck, Tom

Did I misunderstand and you had sewage coming out the clean out? If so that would mean the blockage was beyond, or after, the clean out. Doesn't matter, the blockage is cleared. Possible that someone just had the cap laying on the clean out and not screwed in.

Yes it's coming out the clean out. Cap was off. I cancelled the plumber, flushed toilets again just to make sure they are still working and they are not... so called plumber back... it's still not right ugh!!

I agreewi8th Harold that you have a clog don stream from the CO. Did the plumber clear the clog or is there still a backup out of the CO? If the line's clear and you still have issues then try my solution. Good luck. Tom

Thanks guys~ The plumber was here~ he detected the septic tank which thankfully is only like 4 feet from the clean out cap. They determined roots have cracked the pipe. They did the snake thing from the clean out cap through the pipe that leads to the tank to break it up but said it will happen again in about months or so. For now~ we're good but they said we will need to have that pipe replaced. Seems like an easy fix~ they said if we dig to the pipe~ it will be $325 to replace the pipe ~ if we don't dig it will be $700 something... my husband is very handy~ I am sure he will do the whole job. That seems like a lot ~ even at $325. What are your thoughts?

If I understand correctly, the plumber snake and cleared the lines from the clean out. He found roots in the line. You are on a septic tank. The septic tank is only about 4 foot from the clean out.

If all of that is correct, I would get my shovel and dig up the line between the clean out and the septic tank. It won't be very deep, only about 2 foot or less. Repair or replace the pipe. Should be fairly easy since it is PVC.

I would also remove the tree, bush or what ever the roots are from. They will grow back.

That is what I would do and I am 74 years old. I might or might not hire someone to do the digging since there are plenty of laborers around looking for work. Most likely I would just dig it myself since it is only about 4 foot..