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Mudball 06-23-2006 04:48 PM

Floor Drain question
Im going to have a concrete floor in a utility room. Im going to have the concrete slope slightly toward a drain in the middle of the utility room. I dont want to tie this drain in with the main sewer drain because of having to install a trap primer or worry about filling a water trap every so often. I would like to just lay floor drain pipe (1-1/2" diam ?) right next to sewer drain pipe and extend right outside the perimeter of the house. My question is do they make something to fit on the end of the drain pipe to keep critters from coming into the house but will let water out when ever necessary ? If so then can you tell me what its called so I can tell the plumbing supply store ?

manhattan42 06-23-2006 05:51 PM

What you are proposing is illegal in most jurisdictions....a plumbing code violation.

Floor drains, at least under the International Codes, are required to be trapped and run to your sewer system, and they require a trap primer or some other means of keeping water in your traps.

One economical solution that your local code office may approve is this:

Mudball 06-23-2006 08:43 PM

Thanks for the help manhattan42 and for the link for that item. I certainly dont wont to intentionally do anything illegal. There are no plumbing codes where we live. One guy already suggested to me about just piping the washing machine drain straight outside instead of into the septic and I said no way. We really dont have to have a floor drain in the utility room but I thought it would be nice just in case any of the many items such as whole house water filter, hot water heater, utility sink, washing machine, water softener in there ever sprung a leak. It would never be used for anything other than in emergency if we were ever away from home. Im not trying to be ungrateful or disrespectful in any way but I just couldnt justify the cost of a trap primer ect...for something that may never be used but once in 50 years (just a guess). Do I have any other options ? Since we have no plumbing codes then would it be that bad of an idea to do something as I originally described ? Just asking from the cheap seats:confused:
Thanks again.

glennjanie 06-24-2006 09:07 AM

Hello Mudball:
The plumbing codes are for the health of the general public, including you. The drain you mentioned is too small, say your washing machine hose slipped out of the drain and it pumped out on the floor. A 1-1/2" drain couldn't carry the rush of water. National Plumbing Code and Kentucky Plumbing Code require a minimum 3" floor drain. You can find a 2" floor drain at the big box stores which would help some. The trap keeps odors out of the living space and an open drain would also have varmits and insects using it. Any screen over the end of the pipe that would keep insects out would be a blockage of the drain. If you are going to use a floor drain at all I would think your health would be worth the extra trouble. That's just my view and I recognize others may have a different view.

Mudball 06-24-2006 11:36 AM

Thanks glennjanie. I think both of you are steering me in the right direction. So let me try another suggestion. If I use the floor drain (its a 2") with a P-trap and I connect it to the septic line then can I make it where the hot water heater or washing machine or maybe the utility sink will drain into the floor drain P-trap so it will stay full most of the time or is that a bad idea due to the fact that if we are still living here when we get older and the kids are gone then the use of these items will not be as frequent. How long would it take for a 2" P-trap to dry out ? Can I make a longer deeper P-trap ? Has this procedure been done in the past without any problems ? Any thoughts ?
I just wont give up will I:D Just thought I would try this one last time.

glennjanie 06-24-2006 02:20 PM

Hi Mudball:
No, I wouldn't drain a sink or washer into the floor drain. However, your water heater has a pop-off valve on it which could be piped down to within 2" of the floor; then you could occasionally pull the lever on the pop-off to fill the floor drain.
Yes, you certainly can make a floor drain deeper, Kentucky code allows a water seal of 2" to 4". The 4" water seal would cause it to take longer to evaporate. This deeper P-trap can be made up with a return bend, a short piece of pipe and an ell. The depth of a trap is determined by measuring from the top of the return bend to the bottom of the outlet pipe after the ell (non-technical terminology). You will know when to add water when you look down in the drain and don't see a full round circle of water or if you smell it.

manhattan42 06-24-2006 02:27 PM

Most Tennessee jurisidctions appear to use the International Plumbing/Resdiential Codes so don't be presume there isn't a plumbing code requirement were you live.

Glennjannie is correct in that most codes (like the IPC/IRC) require a minimum of a 2" floor drain and local variations may require large waste receptors. He is also correct that sinks and washers cannot drain directly into a floor waste receptor.

However, there are a myriad number of ways to create a trap primer by having the standpipe from a washer or sink prime the trap.

But if you want a long term "worry free" trap primer, you might consider one that work automatically by intermittantly opening a valve on a water supply line to fill the trap on a timed basis. Works kind of similar to an automatic fill valve on a boiler. This way you won't have to rely on anyone using a drain or fixture to keep the trap filled. Here is an example:

You should probably contact your municipal plumbing code enforcement office to get their feedback as to what is acceptable.

Square Eye 06-24-2006 03:55 PM


You could just superheat your floor and open a window when it gets wet and then the water would evaporate and the steam would go out the window.

No more priming the trap!

Mudball 06-24-2006 08:32 PM

Thank you all very much for all the help. Thanks for keeping an open mind for my suggestions as well. I will be sure to install a trap primer for sure:) . One guy told me a while back that if I used a trap primer that it would be mounted on my utility wall and it would be set to release a slow drip which would flow to the P-trap. He also suggested to use a 1/4" tube (polypropylene ?) from the primer to the trap...sound right ? I was wondering if a tube would be good to use under a concrete slab. I want to make sure that I use the best quality materials for the supply line feeding the trap so I wont have to worry about it later which is why Ive been so reluctant to do this in the first place. Any suggestions on the supply line from the primer to the P-trap ?
Thanks again very much.

glennjanie 06-24-2006 10:04 PM

Hi again:
If you buy a floor drain with a trap primer inlet it will probably be 1/2" and I would use CPVC pipe to feed it. Or, if you use a 4" water seal and just pour a quart of water in it once a month you could forget this trap primer business.

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