Sewage in Basement

Any thoughts on why this is happening? Any thoughts on a solution?
We have lived in this house for 20 years without a problem.
Now we are having problems with sewage coming through the floor drain in the basement. It forces the draintop off and "explodes" sewage.

This is a ranch home with a full basement. We have been able to notice that it is likely to happen during or after someone takes a shower in the main bathroom. But it is not the case that every time the shower is used the problem happens. It does not happen when someone takes a bath in the tub that the shower runs into though.

We called a reputable sewer cleaning service and they did the usual "clean-out" and found no roots and no problems. It happened again about a week after they were here. When they came back they made sure that water from that bathroom left our house appropriately and it did so. We are on a corner lot in the city. The first time they ran the line to the front of the house and determined it was clear and not clogged. The second time they also made sure it was running freely to the other street. The city inspectors office suggested a camera look but the sewer cleaning service said they could do that but it was not necessary as it is obvious there are no clogs and all is running freely.

Any ideas on what is happening here? Any ideas on how to stop this horrible explosion of sewage into our basement? I cannot say for sure 100 per cent that it only happens when a shower is taken in the main bath, but our investigation shows a possible cause and effect there...at least the last four times it exploded that is what happened just prior to the sewage coming in there.

It is not just a little bit that is coming in. It pushes up the sewer drain grate and comes in to about a 4 - 6 foot diameter.

I looked at a 4 inch float sewer plug at the hardware store last night. If we use that would the sewage just come out somewhere else in the house?

I'm really baffled as we have been here so long and the problem just recently began.

Thank-you for your observations and ideas.

I'm no pro, but could the vent be blocked somewhere? Vents are used (among other things) to discharge sewer gasses and sewer pressure. If the vent is blocked, it could be forcing gas up through a trap. I would GUESS that if you capped the floor drain, you'd see the prob somewhere else. But (like you probably are) I'd be afraid to try that experiment...

A number of years ago, I had a similar problem. It turned out to be a huge ball of grease in the manhole where my line dumps into the main sewer line. There was a fast food restaurant two blocks above my home that had a faulty grease trap. The grease washed down the line until it dumped into the manhole where it the solidified and plugged the outlet of the manifold. I'd suggest you at least check where your line empties out and see if as similar blockage has occurred.

Have the city run their camera through their sewer main. That's what your tax dollars pay for. They may him-and-haw about it, but if you press the issue, they'll do it.

Q: Does the water come from a floor drain, or from your clean-out (cap that's on your main sewer pipe)? Does the water go back down the floor drain, or do you have a puddle until somebody comes out to fix it?

The water/sewage comes from the floor drain. Sometimes we do not discover the explosion of sewage for a few hours or even a half-day. The water goes back into the floor drain leaving the deposit of sewage that needs to be cleaned by us manually. The floor drain grate is forced off the floor and the sewage sprays up and leaves sewage at about 3 feet to 6 feet diameter.

The city told us to have the sewer company do the camera work at our cost. Sewer company said it would be expensive but said the parts they would see would come back clear. (This is based on the tests they did). How do I put that back in the city's hands? What specifically do I ask for them to do with the camera that would be in an area that is further away from where the sewer company would go?

Have the line cameraed and have them make a video tape of it. Be sure that the camera goes all the way to the main on the street. Be sure also to have flushed the line well with water B4 the camera does its work. The if the camera shows nothing wrong give a copy of the tape to the city and ask for you $$$ back.

Call around for for prices from different companys that do camera work first and be sure to ask B 4 they come out that they can make a tape of it. When they arive to do it be sure you have a tape and after the tape is made play it and be sure it is on tape B 4 you pay them.