Drain in residential garage with septic

Discussion in 'Canadian Plumbing Code Questions' started by encoad, Jun 18, 2014.

  1. encoad

    encoad New Member

    Messages:
    15
    Location:
    Ottawa, Ontario
    Hi All,

    I've been reading this forum for a while out of interest and now I have a question I hope someone can answer.

    I am building a new home in Greely (Ottawa) this summer. I would like to put a trough drain in the garage floor which drains into the septic system. I know that you cannot do this in Ottawa if you use the cities sewer system, but nobody seems to know if its ok to do when you have septic.

    I've looked into the OBC without any luck. Nobody at the city seems to know and they say it will be up to my inspector, which is not particularly helpful since I need to order the grate.

    Any suggestions on where I find out definitively?

    Thanks!
  2. Terry

    Terry Administrator Staff Member

    Messages:
    15,130
    Location:
    Bothell, Washington
    Just off hand that seems like a poor idea.
    Most people are trying to prevent more water going into their septic and septic drainfield. Taking runoff from the driveway is only going to make things worse.
    In the Seattle area, runoff from roofs and driveways go into ponds or underground storm retention storage. Those are designed to hold the flash flood of a heavy rain, and then disperse out at a slow, steady pace. Often a hole is drilled in the output that is similar to what a wooded and virgin growth would have allowed.

    If this is for the garage floor, you may need something for oil seperation.
    Last edited: Jun 18, 2014
  3. encoad

    encoad New Member

    Messages:
    15
    Location:
    Ottawa, Ontario
    Hi Terry,

    Thanks for the reply. I'm not looking to drain the driveway, just the garage. It will not be much water, just snow melt and very occasional car washing. I just don't want the water running up to the doors and freezing them shut.

    I do not plan to wash any oil into the system, would even a small amount in case of a mishap be dangerous for a septic system? Should I put a sump pump and sent it into the lawn instead?

    Thanks!
  4. cacher_chick

    cacher_chick Test, Don't Guess!

    Messages:
    3,249
    Location:
    Land of Cheese
    In the U.S., most states will not allow a floor drain in a garage unless there is an oil/water seperator installed. If the car leaks oil and it makes it to the sewer or into the ground, the Ministry of Natural Resources will charge you for the environmental cleanup.
  5. leejosepho

    leejosepho DIY scratch-pad engineer

    No, any drain installed in the garage floor will ultimately cause trouble and/or be disallowed.

    Have your garage floor poured with a slope toward its own door out onto the driveway, then use a squeegee to push "snow melt and very occasional car washing" on out if it does not get there on its own. To keep water from running up to or through the door(s) going into the house, have the garage floor lowered a bit. To keep water from freezing under and just outside the garage door, have some heating mat installed there and add a french drain with a grate between the garage and driveway.
  6. encoad

    encoad New Member

    Messages:
    15
    Location:
    Ottawa, Ontario
    Hi All,

    Just to answer my own question, in the city of Ottawa, (and probably all of Ontario, maybe all of Canada), a drain in the garage is permitted under the Ontario Building Code. The only condition is that you must have a P trap and appropriate vent. It must drain to the septic system or city sewers.

    If this was a commercial installation where cars are worked on, you would need to have a oil/water separator.

    Thanks
  7. mikeplummer

    mikeplummer Plumber

    Messages:
    190
    Location:
    Ontario, Canada
    You are correct in your interpretation that they are allowed. However, most municipalities do not want them connected to the municipal system.
    Our inspector usually suggest to run in it to a "stone pit" somewhere on your property - which would usually be about 2'-3' square and deep filled with clear gravel and lined with landscape fabric around
  8. mikeplummer

    mikeplummer Plumber

    Messages:
    190
    Location:
    Ontario, Canada
    You are correct in your interpretation that they are allowed. However, most municipalities do not want them connected to the municipal system.
    Our inspector usually suggest to run in it to a "stone pit" somewhere on your property - which would usually be about 2'-3' square and deep filled with clear gravel and lined with landscape fabric around
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