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Backups with finished basements, sanitary sewer

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  • Backups with finished basements, sanitary sewer

    Finished basements and the possiblity of sanitary sewer backups. What are you doing or advising customers can be done to help reduce the chance of waste water damage?
    Thanks, Dennis........

  • #2
    Hi, Dennis: I'm not a plumber, but I know they make a back water valve that can be installed. I don't know the pros and cons of them. Maybe some of the plumbers here can comment on them.


    • #3
      anytime a plumbing fixture drain is below the level of the downstream manhole or curb, a backwater valve is required to prevent waste from the public sewer getting back into your fixtures incase the public main backs up.

      the fixtures that are connected to the backwater valve can only be the ones below the level of the manhole. upper floor fixtures can't be connected to it.

      the back water valve has to be accessable for cleaning and you don't want to snake into the valve. you'll get your cable caught

      i'm not a big fan of these valves, as they tend to stick and not close or open 100%.

      phoebe it is


      • #4
        backwater et. al.

        I'm with you, I've never been a fan of backwater valves. I understand their usefullness, though.

        The real solution for finished basements is a combination of backwater valve and an exterior ground-level cleanout.

        Pulling the plug from an outside cleanout is much preferable to pulling the plug from an overhead cleanout in a finished basement. Not only does the homeowner not get a dookie flood in their basement, I don't take a dookie shower.



        • #5
          Without knowing all of your elevations it is hard to give you an exact answer. A few things I wanted to clear up though. Rick’s post is right on except for a few items. The code use to talk about the curb elevation but that language was dropped 12-years or so ago. All fixtures which have a flood rim installed below the next upstream manhole needs to be protected by a backwater valve.

          Fixtures which have flood rims which are above the next upstream manholes cannot be drained through the backwater valve. The reason to not drain fixtures through a backwater valve unless they need it is they are very problematic and can clog often. Still you need to check your local codes because in Southern Nevada if one fixture in a single family home needs to be drained through a backwater valve all the fixtures can be drained through the backwater valve.

          While I hate backwater valves and try to design jobs that don’t need them I won’t eliminate one that is needed. I have represented both Municipalities and home owners in major law suits due to homes ending up with several feet of raw sewage in the home. Understand the backwater valve is not to protect the home from sewage from within it is to protect the home from all of your neighbor’s sewage should the main sewer in the street backup.

          Assuming you do not need a backwater valve the exterior clean out can help assuming the exterior elevation is below the flood rim or the fixtures in the basement. However I would make sure you have an exterior cleanout regardless of the height.

          "Somewhere a Village is Missing Twelve Idiots!" - Casey Anthony

          I never lost a cent on the jobs I didn't get!


          • #6
            There is a product, I believe it's called "sewer popper", which will not prevent backflow but can provide some type of early warning in some cases. In the case of a basement bath I'm pretty sure it wouldn't work unless grade level was no higher than basement slab level. I've never installed one, although I have one riding around on my truck, but for people who have recurring back ups and either don't have the money or the will to repair the problem, it could be helpful as far as letting you know that you need to have it cabled before something in the house backs up.

            You will need an outside clean out (the farther from the house the better as long as the cleanout access is still below or at the basement slab level and the cleanout is located between the sewer trouble spot and the house). You remove the c.o. plug and screw in the sewer popper. Once you've done that you simply set the float on top of the base of the sewer popper. The base and the float are chamfered to seal the opening but otherwise the float is simply held in place by gravity (you should not use any pipe dope to try to improve the quality of the seal!). When the sewer backs up to the point of the float, the float is pushed out of the top of the pipe and I'm sure you will get the contents of the pipe on the ground (but that's a lot better than in your house). Hopefully it's located somewhere that's easy to moniter (but it will probably be in the middle of a 30 year old shrub bed ). Anyway, I really can't say how well they work or if they work at all, but it's a pretty inexpensive way to get some early warning if they do work. Also I haven't looked into what the code will allow with respect to this device, so as always, check it out first. If anyone has any experience using one of these I'd be interested in knowing how well they work or don't work.


            • #7
              I understand the grinder pump & check valve better now. I can see how this protects a basement. The waste would only be from the basement toilet not the neighbors.