Any plumbers in the house? Drain trap primer

Hi All,

I'm redoing my 2nd floor laundry room with a new sink and faucet. I started removing the old faucet and noticed it has a plastic line running from the bottom into the wall. I've learned this is probably a drain trap primer for the floor drain. (References: here and here).

Of course the new faucet that I bought doesn't have a fitting to reconnect that line, so what should I do? Just cap it off and pour some water into the floor drain once in a while? Or is it possible to tap into tap into another location - like the outlet from the sink?

Any advice appreciated!

From those links you posted, looks like you can have any source that occasionally sees water connect to that line, OR you can pour water down there occasionally as you suggested. The drain line on a sink is usually plastic and it should be pretty easy to put some kind of a "T" in there, and "cap" the tee...then you should be able to drill and tap into the cap for a line to connect to the existing line. I think that is what you were suggesting, and probably the way I would go...

Just to clarify....I am NOT a plumber, but a homeowner

Thanks Ziggy. Yes that is what I was thinking, just tap into something that occasionally sees water like the sink drain pipe. Seems like a good option.

Thanks for providing a second opinion - I just wasn't sure if I was warped by my years of T-ing boost lines in the DSM!

I'd highly recommend you buy the proper faucet. You want to make sure the traps under your floor drains stay filled with fresh water. It provides an odour and sanitary 'block' from the sewage system to your basement. When you open the valves on this type of faucet, water is allowed to pass through the mouth of the faucet and into the sink but a decent amount of water also bypasses the sink (in the faucet) and is rushed into that plastic line to help supply fresh water to your basement floor drain traps. Ziggy's suggestion probably won't work as a drain line doesn't have any pressure while your faucet will see XX.XXpsi worth of pressure. That line is pressurized like any other domestic water supply line to primer the traps. Drain water with no pressure just won't do the job IMHO.

For future reference, most of these primer systems use the water from a laundry faucet.

I highly recommend you bring it back to the store and buy the proper one.

Thanks Tim. I can understand that perspective, but there don't seem to be many faucets that provide a provision for that primer line. The ones I could find weren't my taste and won't work with my sink (single hole).

...but maybe I can find a way to make this work by adding a tapped fitting to the end of the faucet's sprayer hose, I'll see if that's possible.

There are timered solenoids that you can buy to replace the faucet. It takes a little bit of plumbing but essentially you're looking to have a waterline hooked up to a solenoid which is on a timer system that goes off once or twice every few days to feed that primer line. More often then not, you can find this plastic primer line running down an exposed wall in a basement into the concrete slab. The solenoid is easily set up in your basement utility room.

+1 get a proper faucet or sink for that matter, makes life easier. Everything tim had mentioned about the line providing pressure and clean supply of water for the fumes and sewage is some important stuff

btw what do you intend to use this next sink for? perhaps you can modify the sink to accept 3 holes?

Hang on a sec Jeff, this is a second floor sink?

Where is the floor drain this is supposed to be keeping the trap full of water? In the basement? Does the house have a water softener? How about the furnace, where does it drain it's water?

If this is protecting a basement floor drain, it might have been a provision for a home that had no downstairs laundry when constructed, no softener and a furnace draining outside. Any of that can supply the water you need, for free, without needing to go to an industrial looking laundry sink tap for your second floor.

P

Yea, you can probably use the condesate line from the furnace.

Hey guys, thanks for your continued interest.

I could be wrong, but I don't think the basement drain has anything to do with it.

This is the second floor laundry room, with a sink and a floor drain. I think that little plastic line is just priming the floor drain.

I guess the idea is that the floor drain wouldn't normally see water (nothing drains into it) so it needs an occasional supply to keep it full. That little plastic line runs from the faucet, through the wall, under the floor, to the floor trap. Of course I don't know for sure because the line runs into the wall and then disappears.

The faucet I'm using has a pull out handle with a hose. If I can find the right fitting I think I can "T" off of that hose and get this solved. ...but of course it uses some weird metric fitting that none of the big-box stores have a fitting for!

Ya, I guess it is same idea...just on the second floor...

I am still not convinced you need to feed that under pressure. I would think if you "T" off the BOTTOM of the waste pipe from the sink, you would see sufficient water to keep the floor drain from drying up. Also, it would not surprise me if when you see a large discharge all at once (like the washer emptying) if that didn't back up into the trap for the floor drain.

If it was me, I would try that first because it is cheap and easy, and then keep an eye and see if it ever dries up....

I like the idea of using waste water, however soap scum builds in drains, especially on horizontal runs or in P-traps and may clog your feed. So place your T strategically if you are going to go down this path.

The cheap man's fix is to check up on the trap from time to time and fill it up as necessary. You only lose water in that floor drain trap from evaporation.

P-traps should never be used as tee's for any lines. If the trap under your sink loses it's water trap, a whole slew of odd sewage smells will come and fill up your nice laundry room.

I wasn't talking about tapping off the bottom of the "P" trap, but the bottom of the straight (slightly sloped) run AFTER the "P" trap. That should see water only when waste water is flowing, and I would think gravity would feed enough water to the floor drain to keep it from drying up...

A floor drain on the second floor? Wow, not what I expected

P