Routing a Basement Floor Drain
bongo30
| Posted in General Questions on
We are building a home in NY, with a full basement which will have a tank water heater and a washing machine. Our specs provide for a floor drain with Trap Primer. Any ideas where to route the floor drain? We have a septic tank (no municipal sewers) and drywells. Just want to make sure whatever we route it to, won’t back up back into the house. Any suggestions? Thank you.
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I had a similar setup in a previous house. All drains, including those in the basement, were routed to the septic system (in this case a large holding tank).
That’s what we were thinking of doing but my fear is the septic backing up into that basement drain, since it’s the lowest point in the house. What precautions did you take, if any, to prevent that from happening? Thank you!
svetok,
Check with your municipality. Oddly, some preclude running floor drains to septic and some require that it must go there. On houses here they tie into the perimeter drain system.
You can preclude the risk of either water or septic backing up into the basement with a back-flow preventor valve. My own preference is also to forgo tap primers in favour of filling the never used trap with mineral oil.
The general rule is that water that comes out of a pipe inside the house has to go to a sanitary sewer, water that comes from outside of the house gets dumped outside the house. The purpose of your floor drain is to protect your finished basement if your water heater or washing machine springs a leak. This is plumbing water and should go down the sanitary sewer.
Most areas now are making floor drains go to the septic system. The reasoning is that stuff going down that drain is often not just rain runoff, so it needs to be considered as "nasty stuff". Rain gutter drains and stuff like that are usually NOT supposed to go to the septic tank (same goes for sump pumps), since those are supposed to just be storm runoff.
A quick call to your local building department should get you an answer -- this should be a very quick and easy question for them.
Bill
Understand it is very unlikely that the septic tank will backup into the basement because the tank itself should be installed at a lower elevation than the basement floor if there is a problem with the tank or the drain field the water will leak out the top of the tank and onto the lawn because of its lower elevation.
I have to ask will your footing drains be able to drain to daylight at an elevation several feet below the basements floor elevation.
Walta
Walta,
Most septic tanks have sealed tops to contain odors and are buried deep enough to preclude effluent from forcing its way through the hatches. It's not at all unusual to have the sewer lines to the house back up into the structure.
Our footing drain will be going into a drywell 30 feet away from the house. We don’t have an option of routing to daylight unfortunately.
If you have a HRV in the basement you could pipe the condensate water into the floor drain trap to keep it primed.
I don't understand why the floor drain would be any more likely to back up into the house than the laundry drain a few feet away or the drains on the first floor.
DC,
The floor drain is lower. Long before the other drains would back up, the lowest level would be feet deep in water.
I remediated a house where the slowly failing septic system meant the 4" line going to the tank was often backed up. By the time the owners would notice something was wrong - usually the basement toilet not flushing properly - there would be effluent in the laundry room from the floor drain.
I take your point though. If you stop the floor drain from back-flowing, the problem will just move upstream.
If the laundry is in the same room the standpipe for that is going to be what, 36" higher? Maybe a couple gallons worth of pipe? The septic system isn't going to be backing up because the level inside the tank is rising, it's going to be backing up because waste is flowing in with no place to go. A couple of gallons isn't going to make a difference. At least with a floor drain in time it will drain back into the tank.
DC,
Your description is exactly why I'm so glad our floor drains are not tied to the septic system!
I only know about how they did mine its lid is far from air or water tight.
I had it pumped for the first time the driver was surprised that a tool was needed to remove the covers to pump it.
He said the lids normally just set in place.
Every county seems to have a different set of rules.
They did want to know if the tank lid was buried.
Walta
The lids are often precast concrete with a beveled edge to set into the access holes in the tank. While those don't typically make much of a "seal", over time soil and plant matter tends to get in and pack tightly enough to make that "seal" a lot more sealed! When I had my tank pumped out last year, I had to dig up those access covers, and they were sealed to the tank by dirt and plant bits well enough that it took some effort to pop them off. When I set the back in place, you could seed gaps around the perimeter and they didn't site flat (they'd wiggle a bit). After a few months, the ground settled again and "sealed" the lids and they don't move anymore.
BTW, you can get float switches to install in the septic tank to give you an early warning when the tank is getting higher than it should be. The interesting part is that a septic tank is normally nearly full -- liquid effluent goes through the tank, and into the leach field where it drains away. The purpose of the tank is to collect solids, not to hold liquid. This means that a typical tank doesn't actually have a whole lot of extra capacity to handle things like the emptying of a large bathtub. If the leach field is getting clogged up, it takes a lot less water than you might think to cause the tank to overflow.
Bill
Here is something completely different yet somewhat related if your municipality will allow it. This will also cause less stress on your septic: https://oasisdesign.net/greywater/createanoasis/