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Discussion Forum

Basement floor drain

musashi | Posted in General Discussion on October 4, 2006 03:43am

Hello:

I am adding an addition to the back of my house, and before I pour the concrete slab for the floor, I want to put a floor drain in it.  The addition is going to be a laundry room, and is 30″ below the grade of the back yard.

The downspout for the rain gutter on the roof runs into a vertical 4″ piece of cast iron, which then turns horizontal as it goes though the stone foundation wall, and becomes the main drain running the full length of the basement floor.  Can I put a ‘Y’  in here (that is, just outside of the foundation wall), then run my new floor drain (with a trap) into the main drain just after it turns horizontal?   

Something tells me that I am asking for trouble if I do this. Will a heavy rain cause water to back up into the new room?

Thanks for any advice you may have.

Alex

Outside of a dog, a book is a man’s best friend. Inside of a dog, it’s too dark to read.
-Groucho Marx
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Replies

  1. peteshlagor | Oct 04, 2006 04:15pm | #1

    The downspout for the rain gutter on the roof runs into a vertical 4" piece of cast iron, which then turns horizontal as it goes though the stone foundation wall, and becomes the main drain running the full length of the basement floor. 

    This can't be legal in your town, can it? 

    Methinks you got to deal with this issue before the drain.

     

  2. Tim | Oct 04, 2006 04:43pm | #2

    In most cases, roof drains are dumped into a storm sewer if not not "run to daylight". IF your roof drain is run into the sanitary sewer, expect the inspector to notice during this addition. Even if you don't get hit for a clear violation, it is inappropriate to run site drainage, which include roof downspouts, into a sanitary sewer. You cannot attach any building drain to the storm sewer, with the possible exception of a dewatering sump (i.e. from footing tiles and the like) and that, by most plumbing codes, would have to be an indirect connection. The floor drain in your addition will have to be connected to the existing sanitary drain with the rest of the house.

    1. User avater
      BillHartmann | Oct 04, 2006 05:04pm | #3

      What you and Pete said is true for NEW CONSTRUCTION.In some areas is was common practice and might have even been code (if there was a code them) years ago.Now the question of what this "main drain" is. Is it sanitary (or combined sanitary/storm). If so then it fine to tap into it for the floor and washer drain (assuming it is big enough).But the gutter drain PROPABLY needs to be rerouted. I put in the qualifer as the last time this came out someone said that there city sould not allow surface discharge and required them to use the old combined storm/sanitary system.

      1. cameraman | Oct 04, 2006 05:25pm | #5

        This is a problem facing all communities, in our town of pop. 5,500. Any house built before 1967 was legal to tie in the downspouts, sump pump, and weeping tiles. We had our own waste treatment plant and then the "solution to population was dilution"

        We are now enforcing ordinances on the books to seperate storm from sanitary. Our engineers tell that a city wide separation would cost approx. 24 million $$$$$.

        We have abandon our treatment system and are hooked up to the county. Our treatment charges on a dry month is approx. 15-17 thousand $$$. On a rainy month, like it's doing now in MI., can exceed $80,000.00 per month. We are paying to treat a lot of rain water. Plus if we don't take action we will be fined and billed excessively by the county. The county system is way over capacity, the have to pay for improvements.

        Boils down to pay me now or pay me more later!!!  This is how important separation is!!

  3. BryanSayer | Oct 04, 2006 05:22pm | #4

    Different towns/citys/counties/states have different code requirements. And they are different now than they were back when.

    In general, outside water goes to outside drains, which are for storm water. Thus it goes to either the storm drain or a drywell, or daylighted to run down hill away from the foundation.

    Inside drains go to the sanitary sewer system.

    But some areas have banned floor drains below grade.

    Ask your building dept. what to do.

  4. User avater
    BossHog | Oct 04, 2006 05:26pm | #6

    Aside from code issues, I think it's a REALLY bad idea.

    If your sewer gets plugged outside of youer house somewhere, the water from the gutters is going to come back into your basement in a big way. And it may not happen while you're home to do something about it.

    Money can't buy happiness. But it sure makes misery easier to live with.
    1. john_carroll | Oct 04, 2006 05:40pm | #7

      Like Boss says, tying the roof runoff perimeter/slab drain is a bad idea. I've done extensive repairs on houses because of this detail. One house had three ft. of water in the basement. A huge amount of water flows off the eave of your roof; it can cause big problems if the drain line gets clogged.

  5. musashi | Oct 04, 2006 05:55pm | #8

    Thank you all for your suggestions and advice.  To clarify a bit:

    I live in Brooklyn, and have an attached brick house that was built in 1915.  It is entirely possible that this system was put together when the codes were different than they are now.  By the way, in addition to the floor drain I will also be putting in a washing machine standpipe.

    I am putting a dry well in the garden.  The perforated pipe draining the new footings for the addition is draining to this.  Should I reroute the storm drain to this?  How big does the drywell have to be to handle a big rainfall?

    Taking the storm runoff out of the equation, am I still asking for water to back up? Bill Hartmann seems to say it is ok; BossHogg says no.

    Further thoughts?

     

    Alex

    Outside of a dog, a book is a man's best friend. Inside of a dog, it's too dark to read.
    -Groucho Marx
    1. peteshlagor | Oct 04, 2006 06:46pm | #9

      Doesn't Brooklyn have storm drains?

      That's where these outside drains need to go.  As someone said, ask the BI.  Better that you should ask as opposed to being caught, directly or indirectly.

       

    2. User avater
      BillHartmann | Oct 04, 2006 07:07pm | #10

      No Boss and I are saying the samething, but going at from a different direction.First we don't know what the existing drain line is.I said IF it connects to the sewer system and IF you remove the downspout from it, then you can reuse that line for the floor/washing maching drains.But even so there is still possibility of getting backup from the sewer system. So plan on installing a "check valve". They use a different term, but funcitonal that is what they are. But again check the city. The need for them depends on the depth of the sewer lines, and more inport the height of vents (manholes) verse the height of the drain in the house.

      1. musashi | Oct 04, 2006 09:14pm | #11

        It is the sanitary drain.  My sinks and toilet drain into there farther down the line, and then it goes to the city sewer.  I don't know what the story is with a storm drain.  This is all that I seem to have, and the other houses in the row appear to be done the same way. 

        Is a big dry well a viable option for the storm drain?

         

        Thanks again,

        AlexOutside of a dog, a book is a man's best friend. Inside of a dog, it's too dark to read.
        -Groucho Marx

        1. User avater
          BillHartmann | Oct 04, 2006 09:30pm | #12

          AFAIK yes you can use a drywell.But you need to have aranges for what happens when it is full and overflows. The excess needs to drain to the street without causing more problems.

          1. musashi | Oct 06, 2006 04:45am | #13

            Thank you for your help. I went to the home center today, and bought a large and tough plastic garbage can, some gravel, and some 4" PVC sewer pipe. On Sunday, I've enticed my father-in-law over with promises of all the beer he can drink, and we will dig ourselves a drywell. Once again, I appreciate your help and suggestions, as well as those of everyone else who replied.AlexOutside of a dog, a book is a man's best friend. Inside of a dog, it's too dark to read.
            -Groucho Marx

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