Heavy rain = sewer backup

[joe beagle]

Hello,

The problem:
Over the course of 15 years, my sewer line has backed up five times in my 60-year-old house.
It seems to happen when rainfall exceeds one-third of an inch in one storm. The flooding comes mostly through a toilet and to a lesser extent through a laundry sink drain and the washer drain. The water eventually flows out through another sewer drain, but not before rising to 2-3 inches. It probably wouldn't be a problem, except the floor has to be hosed down each time, and there is a finished rec room down there that we would like to use.
My questions:
1. What are the likely causes of this type of back up? Should I assume installing a back-flow preventer would be called for?
2. It sounds like most of the plumbers I have talked to want to start with a camera inspection. Is a camera inspection always the best way to start?
3. Are there questions I can ask the plumber to try to make sure he is doing a good job at analyzing the video?
4. I am a diy junkie. Should I try to do the camera inspection myself? From what I've seen on the internet, interpreting the video is not necessarily an easy thing to do, and it might be more than worth while to pay a pro.
Thanks,
Gary

By the way, I have to say that this site has got to be one of the best on the Internet!

 

[Standardairconditioner]

Why do you think a camera inspection ISN'T the best way to start?

An assessment and evaluation by observation is the first thing that anyone, professional or DIY, should start.

You're right about a camera being not easy. A lot of DIY's usually end up getting a cameraline stuck in a pipe elbow, that makes rental companies happy as they just permanently purchased it.

It would be foolish and wasteful to just start digging up concrete in your basement to install "something".

Plan and roadmap the solution. Either hire a professional to do professional things, or DIY to do professional things. Nothing wrong with DIY as long as a DIY does professional things. DIY's often cut corners for the cheap and easy way out, and then end up causing more regret and damage costing more.

 

[Sponsor]

 

[Reach4]

Are you feeding into a city sewer? I presume so. Start by talking to the sewer department, and talking to neighbors who are downhill from you. If the neighbors have/had sewer backups, a camera is not going to provide relevant info. As they fix their problems, yours increase. The sewer department usually knows where such problems occur.

There are various solutions, the best of which is overhead sewer. Yes, it is more costly. Other people's **** is backing up now, so that is worthwhile. Budget $14000 to $18000. Advantage includes that your upstairs plumbing continues to work, even if the power goes off.

A backwater valve can be very helpful instead. You would want a design that is "normally open". They can be supplemented.... Normally closed flapper valves will get held open by debris. If you are using water and putting water into the sewer system, even an ideally working backwater valve will not help a lot -- other than limiting backups to your own ****.

There are systems which install a backwater valve and a sewage pump into a buried vault in the front yard. The pump feeds into the sewer side of the valve. It was surprising to me that this was permitted. Budget $6000 to $8000.

I would contact your sewer department. They may have grant money to help you out. They like to be helpful usually. Now they are probably going to be wanting you to direct your sump pump output outdoors rather than into the sanitary sewer. They may have program money to help with that. That is pretty easy DIY. If you and your neighbors did this, sewer backups would be a lot less frequent. Also, when they have backup reports from several people in an area, they will prioritize that area for upgrading the sewer system. They can apply for grant money themselves.

If you don't have city sewers, say so.

 

[Jadnashua]

If you're near the bottom of a hill, probably the only sure-fire solution is the overhead sewer and that requires a pump and basin. Essentially, your waste first goes into a basin, and when it reaches a tipping point, the pump turns on and pumps it out. Since it is going up (often) way above where the city's sewer line is, their waste can't backup into your house. Now, if your power goes out, once your basin gets full, you won't be able to use any waste producing fixtures. Valves don't always work reliably, especially once they get older.

 

[Reach4]

Essentially, your waste first goes into a basin, and when it reaches a tipping point, the pump turns on and pumps it out. Since it is going up (often) way above where the city's sewer line is, their waste can't backup into your house. Now, if your power goes out, once your basin gets full, you won't be able to use any waste producing fixtures.

That is not what is called an overhead sewer. With an overhead sewer, the fixtures above the basement do not feed their sewage through a pump to the city sewer.

 

[Jadnashua]

Depending on the elevation of your home's plumbing relative to the sewer line and how far it backs up the hill, you may need all of the fixtures to drain into the basin and pump it up high enough to exceed the backup. Yes, you could just plumb the fixtures that are lower into one, but if things backed up far enough, once that was prevented from being the outlet, those higher up could backup as well. Getting yours higher than your neighbors may be the only way to prevent it from backing up into your house. Gravity works wonders, and the pump is not ideal until you have to spend time and money cleaning up and maybe replacing contaminated things on a regular basis.