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Community and Q&A

Tying Garage into House Drainage System

arnoldk | Posted in General Questions on
Is there any issues or concern with connecting the weeping tile from my detached garage to the house?

The reason is the weeping to daylight for the house is only 10 feet while the for the detached garage, I would need to run 60-70 feet pass the house to daylight.

The house is a slab on grade which I know doesn’t need weeping tile but the contractor included it in his scoop of work anyways. I figured since I am paying for it regardless and I have a high water table, around 3 week below grade I may as well put there.

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  1. Expert Member
    PETER Engle | | #1

    As you mentioned, you probably didn't need drain pipe around the house because it is slab on grade construction. For the same reason, you probably don't need it for the garage, either. That said, if you are putting a drainage system on both the house and garage, it probably won't hurt to connect them together. Just make sure that the house system is draining freely before adding more load from the garage. You can do this with a garden hose once you expose the house drains.

    I would fill the bottom of the trench from the garage to the house with washed stone above and below the pipe, with the whole thing wrapped with landscape fabric like a burrito. Essentially this is an extension of the drain system, but it will also allow the pipes to drain into the ground, depending on the level of the water table.

    1. arnoldk | | #2

      Hi Peter,

      The weeping tile is already installed as you described it. I'll dig the last 8 feet trench to connect the garage drainage pipe to the house and the outlet of the house is already exposed to daylight.

      They backfilling is happen early next week so I need to get a move on to avoid any delays.


  2. Expert Member
    BILL WICHERS | | #3

    If you have a floor drain in your garage, this might complicate things. Many/most codes now require floor drains to be tied into the sanitary sewer (or septic system), and not a stormwater drain or sump pump. The reason is that floor drains can sometimes get nasty stuff (maybe oil if it's a garage, for example), and you don't want to just drain that out to a stream somewhere.

    On the flip side, code doesn't usually let you drain rain gutters and things like that into the sanitary system, since it puts too much water into the system and can cause things to overflow. Having been in a house once on a combined storm and sanitary sewer, I am unfortunately quite familiar to what that "overflow" can mean in a basement...


    1. arnoldk | | #4

      Hi Bill,

      I did not put a drain in the garage since it would need to be tied into the septic system and also make sure the p-trap doesn't freeze. It was not more trouble and cost than it's worth. The slab will have a slight grade towards the garage doors.

      Thank you,

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