Where does that floor drain actually go..?

[seamlyne]

Here's the setup: The original structure of the house was built in 1920, the basement was poured sometime in the 50's. There are two DWV stacks, both added about the same time as the basement floor, one for the main part of the house, one for an addition on the back.

Having to move a washer/drier to the basement, and I have two choices for draining the washing machine. The main stack for the upstairs bathroom is behind a concrete block wall. Cutting access through that wall, then putting a rubber collar on the stack (which is cast iron) then connecting my PVC pipe is straightforward - I think. If anyone would like to comment on that, I'd be grateful.

The other option is a floor drain in the area where the washer will go. I assume it's an iron pipe because, well, what I can see is shaped like a Tee and is a little rusty around the edges. About 8 or 9" down a horizontal pipe takes over. I've shone a light into that pipe either direction and - using a mirror - can see that it continues in both directions (north to south) as far as the light will shine. Which isn't much, admittedly.

I've been using it to drain a utility sink, and the air conditioner's drained into it for years. It drains fine - the utility sink drains as fast as the washing machine does - so it's vented somehow, isn't it? There's never been the smell of sewer gas in the basement. Flushing the toilets (one uses the stack for the main part of the house, one uses the addition) causes no ripples in the water I can see - come to think of it, I can't remember ever seeing that pipe in the floor without water in it, though the current is slow, north to south.

So, I can drain into the pipe if tapping into the main stack proves too daunting, but I'd like to know what's going on there. Anyone encounter a situation like this before? Is there a way - short of using a jackhammer - to figure out where the pipe goes?

- Wm Morris

[HayZee518]

You can but for the general homeowner it ain't worth it. They make a device that transmits a radio frequency along a conductor (e.g. a metal snake put through a pipe) which can be picked up by a suitable receiver. This will tell you direction and even depth of burial of the pipe. I had a tool like this once (till it got stolen!) I was able to determine buried wires underground in metal conduit and the depth of the burial.

[LazyPup]

The floor drain is most likely tied into the house main drain (the main line running from the base of the main vent under the house and out to the main sewer line which connects to the municipal sewer or septic tank. When you look down into it you are seeing the lateral run of the main drain, therefore there is no trap between the floor drain opening and the main drain under the foundation. Probably the cover of the floor drain has an extended flange on the underside that effects an inverted bucket trap when the cover is in place. If that line is 2 inches or more in diameter it is suitable for installing a laundry drain. Since you will have to remove the cover to tie in your new line, you will have to install a trap on the washing machine riser. That trap must be accessible and it must be not less than 6 inches above the floor and not more than 18 inches above the floor.