I was just helping a friend move into a new house and noticed something odd about the plumbing. Looking under the kitchen sink ... no trap. Looking under the bathroom sink ... no trap. WTF?

The drain lines are all 'new' in the sense that they are PVC, and obviously many decades newer than the house. They have good slopes, wide turns, etc, but the traps are odd. The kitchen sink drains straight down through the floor. The trap is in the joist space of the basement ceiling. Then the line goes mostly horizontally 2'-3' before teeing off to separate vent and drain. Can this really be legitimate?

 

The tail-piece (distance from the fixture to the trap) should not exceed 24", by most codes. If it gets too long, it'll start to smell.

 

Totally bogus, the traps have to be near the fixture, dropping like that means there is little chance they are vented.

 

Yeah, I thought that looked bogus and I couldn't google enough of the plumbing codes to be sure of what I was reading. Thanks.

For the kitchen sink, would installing a disposal make any difference? Would the 24" still start at the sink drain or the disposal outlet, giving them several more inches?

 

Since the trap should be under the sink there is little chance that you would excede a 24in drop; if you plan to install a disposer you should check back here for information before something else gets fuxxed up.

 

If this were my plumbing, I'd probably make it a priority to fix (especially since it's all PVC so will be much easier and faster), but I don't know the owner's priorities, so I'm looking for options to either present or prohibit if he asks ...

Taking a yardstick to my kitchen sink, If it's legitimate to measure from the disposer outlet, there's a chance I could put the trap in the basement while keeping it to 24". Since they would see extra functionality from that option, it would be an easier sell.

Thinking back to the configuration, I don't know if the vents were within range of an under-sink trap, so it would be a bigger project.

So how big a deal is this anyway? How much should I press them to fix it? The traps are about 30" below the sinks (in the basement ceiling) and the tee to the vents are about 30" from the trap. We're in the right town, even if we're on the wrong side of the tracks. There is no sewage smell, even though the house has been closed up for a week or two, so the traps must still have water. Is this urgent to fix or is it ok until they smell symptoms?

 

Some plumbing problems take a while to manifest. A professional plumber would not have put traps in the basement for fixtures on the 1st floor. I'd want this fixed correctly as it may involve opening walls to provide venting.

 

>>>Taking a yardstick to my kitchen sink, If it's legitimate to measure from the disposer outlet, there's a chance I could put the trap in the basement while keeping it to 24". Since they would see extra functionality from that option, it would be an easier sell.>>they would see extra functionality from that option,