I thought the fork was in the road.

Is this right.


No, it’s left.

Plumbing drains should have a 1/4" per. ft. downward slope. All bends should be no greater than 45 deg. or a long sweeping 90 deg. elbow. (Two 45 deg. elbows = 90 deg. long sweeping 90 deg. elbow.)

** Note:** Their are exceptions to every rule!!

** Plumbing vents** should have a 1/8" per. ft. downward slope. (Hard 90 deg. elbows are acceptable as long as the pipe is not used as a drain also.)

** Special Note:** When one or more drain lines merge to another drain line the connection should be on a downward slope. (I prefer a minimum of a 30 deg. slope to provent backups.)

These are just some simplified rules of thumb to go by. These are not the Be-All-End-All rules of plumbing.

If they need a clean-out there (That is under the sink) it should tell you that they have problems there. I like to see clean-outs on horizontal drains every 20+ ft. Longer than that you need a snake greater than 25’ long and becomes hard to work with even if it is a power unit.

There is no problem with that configuration unless your state or city/county follows the UPC. . .

It is referred to as a “common trap arm,” utilizing a double wye, which is allowed by the IRC but prohibited by the UPC.

I do not like the plastic water feed lines had a friend have one break last Easter when she was away $60,000;00 damage and she could not live in the home foe 4 months .
I always recommend upgrade to burst proof for all appliances .
This includes Washers saw what happens when the rubber hose breaks.
Roy Cooke sr . Royshomeinspection.com

Im wondering if you zoom that pic out a little will it actually show a double trapped sink, which is not allowed. I dont think we are getting the whole picture.


There are two traps, but this is not considered a “double trap.” A double trap is two traps in series (one after another).

This is a “shared trap arm.” As you are in CA, you should know that the CPC specifically prohibits this type of installation.


Are you assuming that there is another trap? We can all assume that there is a trap off the “assumed disposal” which we again are assuming is there. Did you see a different pic than I did?..Its still not right no matter what you call it. Thats what I was getting at. Not a deal breaker tho…Lets not get to excited about something that is simple to fix.

If there is no trap at the disposal/second-sink side, it’s wrong.

If there is a trap at the disposal side (which I am assuming), the entire setup is allowed by the IRC.

Regardless of the presence of a trap at the disposal/second-sink side, it is wrong for CA and the UPC.

I’m not interested in fixing it, I’m only interested in making the right call.

Thanks for your insite Jeff, this was in a condo 3rd floor I have never seen a configuration like this before. No there was not a double trap(back to back) both sides of the sink were individualy trapped.

Which is perfectly acceptable for FL and the IRC. . .

Roy, please tell me what type of material is “burst proof”?

No such animal.