Is my kitchen sink vented correctly? Intermittent back ups and noises.

I live on the first floor condo with two units above me. We came home to a mess in our sink. It could not have been anything we did - nothing was left running. So, I surmise we have an issue with drainage from the units above us. I looked under the sink, and noticed that the vent pipes connect, but then go down into the floor? Is this right? I thought vents should go up.

It seems like we are getting intermittent back ups into our sink the last few days. When we run the water, it drains just fine. But again, today we came home to a sink full of small bits of debris - stuff that I do not think came from our usage, that had backed up into our sink.

This is our third plumbing issue in three days (thanks for all the great advice here). Trying to become more knowledgeable before I call a plumber.

Helpful Plumbing Hints for Residential Construction by Bert Polk Plumbing Inspector Lincoln County

It could be a properly executed loop vent...I'm not sure. Somewhere, there needs to be a vent line going up, but it might be in a different wall.

If there's a partial blockage beneath you, it can build up and will come out the lowest point possible. This might be your toilets or the tub, but there may be multiple lines before they combine and the only thing on the sink line is the one that is partially blocked and that's why it is confined to that sink.

It can get messy in a condo association convincing the others that it is their problem, and not yours. If you pay a management company, sometimes it easier to get them to understand, but it is the condo board you have to convince.

Wow, I assume that's supposed to be some half assed attempt at an island loop? Looks like a mess to me... pretty sure the fittings are all wrong on there, but I don't deal with too many of these, so I'll defer to the plumbing pros on here about that.

D/W should be tied into disposal, not its own trap, the 2 traps on the 2 bowls is probably ok (actually required in my county, but not the norm most places), but the venting looks to be all wrong. You probably need this island loop to be redone.

However, I don't see how the problems here could have caused a backup... maybe someone else can help you more on that front. Seems like there's blockage in the drain below your tie-in, that is causing the whole system to back up high enough that you're getting waste rising up through your drain from the apartments above you. This would be a building problem, if that is the case, not your problem. You should contact whoever is in charge of building maintenance.

FWIW, in a condo situation, there may not be any building maintenance. There may not be a management company. A condo is a form of ownership with various parts segregated to common ownership and limited private ownership. Under most contracts, stuff like plumbing is common ownership except when entirely within a unit. So, you have to read the ownership contract (condo rules) to determine who owns what, and who is responsible for repairs. It's probably a common area (group owned) issue, and then, it's the group of owners, often represented by a board of directors, that needs to approve repairs. Condo living can get complicated...it's not like an apartment you rent - you are the owner, and things like parking lots, common hallways, elevators, etc. are owned by the group of owners. It can get even more complicated if one of the owners rents his unit out.

jadnashua said:

FWIW, in a condo situation, there may not be any building maintenance. There may not be a management company. A condo is a form of ownership with various parts segregated to common ownership and limited private ownership. Under most contracts, stuff like plumbing is common ownership except when entirely within a unit. So, you have to read the ownership contract (condo rules) to determine who owns what, and who is responsible for repairs. It's probably a common area (group owned) issue, and then, it's the group of owners, often represented by a board of directors, that needs to approve repairs. Condo living can get complicated...it's not like an apartment you rent - you are the owner, and things like parking lots, common hallways, elevators, etc. are owned by the group of owners. It can get even more complicated if one of the owners rents his unit out.

Click to expand...

Good to know. Thanks for the info, Jim. Condos aren't really as big of a thing around my area as probably in most places, so I don't have any experience with them. The whole concept lways sounded like a pain in the butt to me... some of the benefits of ownership, but pretty much all of the headaches, and it sounds like from what you're saying, possibly even more. But, to each his own I guess I know most people on here would probably never want to live in an urban row house like I choose to do.

That is one of the worst, and most poorly installed, drain systems I have ever seen. There is almost NOTHING about it that is correct, or even "good" plumbing practice. IT has NOTHING to do with venting, at least not until the stoppage gets worse, and then your sink will NOT drain. The line under the floor is getting obstructed and the management company has to have it unplugged.

It looks like the plumbing contractor got paid by the fitting on that job! I thought all vents had to be above the flood level rim of the fixture before they could turn horizontal.

If this is an island sink, the loop vent might be acceptable, but it does not appear to be executed correctly.
You are not allowed to have multiple traps feed into one waste arm.
The back up you experienced has nothing to do with venting. The main drain is plugged, and one of the pitfalls of living on lower floors is that when the waste from the upper floors cannot drain away into the main, the next lowest path of least resistance is out through your sink.

In condos that I am familiar with, any waste pipes serving more than one unit are the responsibility of the HOA. You need to get them to fix this before your next surprise.

The responsility for the piping disaster under your sink is yours alone.

quote; I thought all vents had to be above the flood level rim of the fixture before they could turn horizontal.

They do, in fact that "vent" is so low that if the drain line were, or is, plugged the waste would just use the vent as an "alternate drain source". WE use "multiple traps on a single drain arm" quite frequently with three bowl sinks. THIS drain setup is NOT acceptable for ANY installation, even an island sink. In fact, there is NO "qualified" plumber, (I hope you are NOT in Chicago), who would ever install a mess like that, (and then use duct tape on the drain tailpiece because he did not know how to stop a leak). When the plumber arrives, be prepared for him to spend the first five minutes laughing and trying to pull himself together after seeing the piping.

An island loop should not have a horizontal section but rather, two 45 degree angled sectons with a 90 on top. The loop should go up as high as physically possible. Oh, and a nice professional Duck® Tape job.

Thats a gorgeous piece of work there, absolutely spectacular, a real tribute to the hack's art indeed, however, if the sink ain't draining it's because the drain is plugged up somewhere. Vents don't make fixtures drain better.