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Basement floor drain. Where does it go?

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  • Feb 27th, 2021 6:26 am
[OP]
Deal Addict
Sep 16, 2013
1808 posts
947 upvotes
SW ON

Basement floor drain. Where does it go?

Please educate me. I have a drain in the basement floor. It's in the area near the sump well and the furnace/AC/water heater. It's about 10cm in diameter. I looked inside. There is standing water and I see a pipe closer to the surface going to the side. I suppose when the water level reaches that level it flows away. Is it connected to the sewer? I am afraid it may drain into the soil. That's why I am asking. Occasionally I poured water in there and it went away. I wonder if I can dump water occasionally into it in winter assuming it goes to the sewer, otherwise, I may create a trouble.

I don't know if there was a code for such things, so the answer can be unambiguous. The house was built in the 80s, southern Ontario.
15 replies
Sr. Member
User avatar
Dec 6, 2017
985 posts
517 upvotes
Manitoba
I have the same drain (or two) in my basement. I always assumed that it is connected to the sewer as a way to avoid flooding as we don't have a sump pump.

I could be wrong though so I'll follow the thread and see the replies.
one more deal and I'm out * involuntary tick*.... :twisted:
Deal Addict
Jun 24, 2015
4528 posts
1336 upvotes
Woodbridge, ON
it goes into the sanitary waste water from the city/

it has water in it because there is likely a trap in there to prevent sewer gases from coming into your house and a pipe to drain furnace and AC condenser discharge into there to prevent it from drying up.
Hi
Deal Addict
User avatar
Oct 14, 2010
1349 posts
803 upvotes
Barrie ON
The drain has a trap like any other fixture in the house. The trap is to keep sewer gasses from entering the house.

Because the sewer drain will normally not have any water going into it (if your lucky) the water in the trap will evaporate and allow the gasses to enter the home. Because of this, a small tube, known as the drain primer, is connected to a laundry tub, or toilet. Whenever the laundry tub faucet is used, or the toilet is flushed, some water is put into the drain and creates a new gas "seal".

Image
[OP]
Deal Addict
Sep 16, 2013
1808 posts
947 upvotes
SW ON
@GoodFellaz, @Rick007, thank you! Very informative. So, it does go to the sewer. I am glad it does. I think my trap primer comes from the furnace/AC but I may be wrong. The good thing that there is water in the trap and this drain hasn't been used for a year or so.
Deal Addict
Jun 24, 2015
4528 posts
1336 upvotes
Woodbridge, ON
my dad has a laundry sink in his basement and there is a trap primer on it but he almost NEVER uses that sink, like once a year. so his furnace and air conditioner has a discharge and it drains it into the floor drain.
Hi
Deal Addict
Jan 11, 2007
3378 posts
479 upvotes
Mississauga
for this floor drain thing i hear it "burping" or "gurgling" sounds coming from it, I had it overflow from a stack block near it earlier in 2020 (i had a plumber fix it) now im scared to put flooring down again as i don't want a repeat of sewer water flooding my basement (it is NOT fun)
[OP]
Deal Addict
Sep 16, 2013
1808 posts
947 upvotes
SW ON
Thinking about this drain brought up another related question. A backflow valve is recommended for the whole house sewer. My house doesn't have it, I think. If I were to install it I thought it would go on the main sewer pipe in the basement. The house has one widest sewer pipe going into the floor and other more narrow pipes connected to it. I assume this is it. Now, with this basement floor drain connected to this sewer pipe under the floor the back flow valve wouldn't save the house from sewer backup flooding from this floor drain. Where is a backflow valve installed normally?
Sr. Member
Jun 26, 2019
821 posts
619 upvotes
alpovs wrote: Thinking about this drain brought up another related question. A backflow valve is recommended for the whole house sewer. My house doesn't have it, I think. If I were to install it I thought it would go on the main sewer pipe in the basement. The house has one widest sewer pipe going into the floor and other more narrow pipes connected to it. I assume this is it. Now, with this basement floor drain connected to this sewer pipe under the floor the back flow valve wouldn't save the house from sewer backup flooding from this floor drain. Where is a backflow valve installed normally?
Outside, on your house's sanitary service connection.

This is probably the most common, but can differ based on case by case.
[OP]
Deal Addict
Sep 16, 2013
1808 posts
947 upvotes
SW ON
SubjectivelyObjective wrote: Outside, on your house's sanitary service connection.

This is probably the most common, but can differ based on case by case.
Does it mean underground and they have to dig to install the valve?
Sr. Member
Jun 26, 2019
821 posts
619 upvotes
alpovs wrote: Does it mean underground and they have to dig to install the valve?
Yeah, they dig down and install it on your service connection.

That way your foundation drains/weepers are protected as well.

Its more common in combined sewer areas, or just poorly designed ones.

Edit: Ill just add that its not uncommon to install it inside, but most of what I have seen has been outside on your service connection.
[OP]
Deal Addict
Sep 16, 2013
1808 posts
947 upvotes
SW ON
SubjectivelyObjective wrote: Yeah, they dig down and install it on your service connection.

That way your foundation drains/weepers are protected as well.

Its more common in combined sewer areas, or just poorly designed ones.

Edit: Ill just add that its not uncommon to install it inside, but most of what I have seen has been outside on your service connection.
Thanks! Do you know if it ever was a standard to install backflow valves? In particular in the 80s. I always assumed the house doesn't have it because I don't see it anywhere but maybe it's underground installed by the builders.
Sr. Member
Jun 26, 2019
821 posts
619 upvotes
alpovs wrote: Thanks! Do you know if it ever was a standard to install backflow valves? In particular in the 80s. I always assumed the house doesn't have it because I don't see it anywhere but maybe it's underground installed by the builders.
It is highly unlikely that they would install a backflow preventer. Maybe in the past 10 years in very specific areas it's been required, but for the most part it's not a requirement nor something developers would want to pay for.

You could try to find your sanitary clean out or scope the line, but it's likely you don't have one.

The main question is do you think you need one? Where are you on your street? Is your sanitary network over capacity or a combined sewer? How deep is the sanitary mainline on your street, etc etc.
Deal Addict
Jun 24, 2015
4528 posts
1336 upvotes
Woodbridge, ON
we kinda derailed the topic already we should be talking about floor drains. a Backflow preventer is great but if we need to discuss it, lets make a new post about it instead of derailing this post, okay?
Hi
[OP]
Deal Addict
Sep 16, 2013
1808 posts
947 upvotes
SW ON
Sorry for "derailing" my own thread. It wasn't derailed because derailing implies negative outcome. I asked another question after the first one was answered and resolved. The second question was answered and resolved as well. I wasn't going to post anymore to this thread.

Thanks, everyone who posted!
Deal Addict
Nov 17, 2012
3172 posts
2139 upvotes
Toronto
If you don’t have a problem, don’t install a backflow preventer. That’s the advice I’ve gotten.

If it fails, it will block your drain and you flood your basement.

Everything has some risk to it, including installing a potential point of failure in your drain system.

Certain situations demand them like areas prone to flooding where the storm and sewer drains are combined (certain areas of Toronto) or perhaps where your house drain connects with your neighbors before connecting to the city sewer line - common in older areas of Toronto with narrow lots. Your neighbor in theory could cause a clog in the shared drain line causing a backup into your house.

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