Hello,

In my house the basement laundry room and bathroom back to the same wall. The previous owner really botched the installation, so I'm redoing it.

The drains on this wall include: a bathroom sink, a washer standpipe, and a utility tub/sink. There is also a toilet that connects under the concrete, and a 2" drain/vent pipe running up from that toilet, I think. The bathroom sink's drain is on a separate horizontal line. The water lines come down from the top.

Here is an image of the current situation (click on it to see the larger version):
http://img212.imageshack.us/img212/5067/currentinstallationna6.th.jpg (http://img212.imageshack.us/my.php?image=currentinstallationna6.jpg)http://img212.imageshack.us/images/thpix.gif (http://g.imageshack.us/thpix.php)

The main problem the current installation has is that the standpipe has no trap, because its trap is located further away from the main drain between it and the utility tub. That trap adds a second trap for the utility tub. As you'd expect, we get sewer odors. Also when the washer discharges water, that water now backs up into the utility tub.

1. Can all three (washer standpipe, utility tub and bath room sink) be put on the same horizontal drain line? Or would the bathroom sink tend to overflow because it's lower?

2. Can one vent line provide venting for more than one drain?

3. This will all be hidden behind drywall, so how do I provide a clean out? Or should I?

Here's what I'd like to do (but am not sure is wise or meets code):
http://img179.imageshack.us/img179/4566/possiblesolution1wl7.th.jpg (http://img179.imageshack.us/my.php?image=possiblesolution1wl7.jpg)http://img179.imageshack.us/images/thpix.gif (http://g.imageshack.us/thpix.php)

4. Are there other things I need to consider? I'm sure that I don't know all I need to know!

Hello AZW:

Check out my picture below...

In this case I would individually vent each fixture. Ptraps under each sink or outside wall for washing machine unless installing a washing machine box inside the wall.

Vent connects in at 48" off finish floor for all this.

Washer standpipe should be 30" minimum out of a 2" p-trap.

I would install a cleanout under each sink and at the washer VENT (just face out toward wall and hopefully cut a nice hole when sheetrocking.

WYE fittings ONLY on the 2" mimimum horizontal drain pipe.

ANY questions..?

MARK

Thanks, that'll be very helpful! Your plan is elegant in it's economy.

Yes, there will be a inside the wall box for the washer, so Ill have to install that trap inside the wall.

Does the 48" above floor height refer to where the horizontal vent pipe connects back into the vertical pipe at the left in the image?

Doing the drains all on one drain line won't cause water to back up into the lower bathroom sink?

Okay, I got it on the WYE's. Thanks for the tip.

Would the cleanouts also be made using WYE's?

Is the correct locations for cleanouts (crudely drawn in blue in following attachment)? Or should they be located below where a individual drain enters the vent/drain, not above?

Here's an easy question... how did you draw those crisp red lines? Very nice!

Hi AZW:

Washing machine box is great just be sure to have pipe 30" minimum from box to trap. 48" does refer to minimum height to connect vent back into pipe on left. NOTE HERE that the fitting that connects vent to stack is an upside down sanitary tee fitting. Let me know if need more info. On this.

I like cleanout in the vents... some inspectors don't. I would install the cleanout in the vent for the washing machine. I would install dandy cleanouts (see picture) under each sink and use union ptraps to make cleaning traps super easy down the road.

I would also put a full-size END CLEAN OUT at the end of the horizontal run near the utility sink. Just branch off with a wye fitting at the end to pick up the sink and then install 90 degree elbow into end, look it out of wall and install an end clean out. INSPECTORS love cleanouts! They also love them to be accessible... ;) Keep that in mind.

Drains will not back up if vented correctly and as long as connection to the main stack is not clogged! Before re-piping this make a cut close to the stack and take a good look into the pipe/connection. If you see any obstruction then remove/scrape as needed at this time. If old pipes then may also want to install another cleanout close to this connection point.

Cleanouts are made using DANDY CLEANOUTS (I'm trying to answer your questions in order... :) ).

Cleanout questions answered above.

Finally, I use my paint program and click on LINE draw.

Let me know if you have more questions. I pop in and out frequently!

MARK

Boy, that's great. Thanks so much!

I can't think of any more questions now, but I'll pop back in if I need help.