Backwater Valve and Floor Drain

Discussion in 'Plumbing Forum, Professional & DIY Advice' started by butchboy, Oct 17, 2013.

  1. butchboy

    butchboy New Member

    Oct 17, 2013
    I live in Chicago and am having a backwater valve replaced that hasn't been maintained for 20+ years. It is inside my basement and the flapper is locked in the open position. My area has major problems with sewer backup during heavy rains. I have two questions.

    1) Is there any appreciable difference between cast iron and pvc (abs) backwater valves? Does Chicago have a code regarding material?

    2) I currently don't have a floor drain in the basement, but since my floor is being broken anyways, I was thinking of having one installed behind the backwater valve. Am I asking for trouble? Assuming the backwater valve is properly maintained, will it reliably hold back the sewer back-flow or is there a possibility I will see a geyser erupt from the drain at some point.
  2. Reach4

    Reach4 Well-Known Member

    Sep 25, 2013
    The wrong kind are normally closed, and the outgoing effluent pushes the flapper open. This is probably the kind you have-- the kind that will fail.

    The better kind are normally open, and close with a float. They require a little drop typically from input to output. These are normally stainless steel or plastic.

    Does Chicago have codes on this? I would be surprised if they did not You might ask in

    Your other alternative, which is more foolproof, is overhead sewers. Yes, it costs more. -- maybe $10000 to $14000 typically. A pit in the front yard can be good, and does not involve digging in your basement. Figure about $7000 to $8000. (bad BBB) (good BBB) Read the stuff on those sites as to how their valves worth. Those plastic valves from Canada look good too.

    Don't try to book the work after a flood. Do it before.
    Last edited: Oct 17, 2013
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  4. hj

    hj Moderator & Master Plumber Staff Member

    Aug 31, 2004
    Cave Creek, Arizona
    NO backwater valve is 100% foolproof all the time. ANY material that gets caught on the seat will prevent it from sealing, although it will slow down the flooding, possibly allowing the backflood condition to clear before the basement floods. The metal ones "corrode", the plastic ones "distort, over time, and anything with a float mechanism will stick in the open position.
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