I'm not a plumber , I always try to fix , repair or build myself whenever it comes to almost anything . My daughter had a sink , commode , and shower installed, in the older home that they are living in ( two story), in the upstairs . The person that put the fixtures in was not a licensed plumber . It appears that he done an over all good job , including a lot of dry wall and replacing a swagging floor . The problem that she now has is an odor coming from the shower drain . It's only noticeable when she is taking a shower . I don't know anything about wet venting of which I have been reading about in your postings . The only venting that I know about is the one that comes out of the roof. By the way she doesn't have one of those either . I was wondering if I could go to the basement and tie into the main sewer line and install a vent pipe to the outside of the house . Do you think that this might elimnate the odor . She does not have any other odors , only the one from the shower . I can't tell if the shower has a trap in it or not , I don't believe it does , I know its connected into the large waste line coming from the commode going down to the basement to the main sewer line . Need Help !!! THANKS

The purpose of a trap is to keep out the sewer gases for health reasons. Is there a trap under the sink?

Nothing against general contractors but most of them should not attempt plumbing.

If you look into the shower drain, below the strainer, can you see standing water? Most likely not by the sounds of things, (the odor).

As for the vent through the roof, either the "plumber" terminated it, it's on the other side of the roof or there was never one to begin with.

Adding a vent in the basement probably will not help the situation, you should have a licensed plumber look things over and perform the necessary corrections needed.

Good Luck. *westchester plumber*



Post Edited

Somehow get access to underneath of that shower and see if there is a trap. If there is, cut a tee inline as close to trap as possible, and install a cheater vent in a vertical run in the wall.

This is not how it should of been done initially, but it will allow for the fixture to take air when needed.


Follow the advice of a licensed plumber; they can tell exactly what is wrong and what needs to be done.

Possibly the vent is located in the attic space. Most plumbers do not want to cut a hole in roof and expose the home being built to outside weather conditions. Usually as soon as a roof is decked it is tar papered. Most penerations need to be coordinated with roofer. If there is no vent then that very well may be where the problem lies. Have someone dump peppermint extract in the outside clean out while you stay inside and smell. If you smell pepperment in the drain then this would be the first area to srart investigating. GOOD LUCK

YOur knowledge of plumbing and description of the job is not enough for us to decide what could be wrong. Call a plumber and have him make the necessary corrections. It may be much more expensive than if it had been done correctly the fist time.

There is a trap under the sink and no odor comes from it . The only time an odor appears is when the shower is running , she also has an exhaust fan in the room and she runs it while she is in the shower . I don't think that the fan would be strong enough to pull the odor from the sewer but I'm going to try to run the shower with out the fan to see what happens . I still think that I'm going to put a vent line down in the basement and run it outside to see what happens. Thanks

Thanks . There appears that any kind of vent was ever installed . I'm going to add one in the basement .

I'm still in the dark on wet venting , I think I know but I'd like for someone that really knows explain it to me . Thanks

I have noticed that you keep saying you are going into the basement and put a vent in...
It is not going to help at all unless this is done correctly with the correct fittings in the correct place. This problem resulted from someone who did not know what they were doing doing the plumbing, don't make the problem worse by charging BLINDLY ahead when you don't even really know what is causing the problem. Call a plumber and fix this correctly. Make sure that the exhaust fan and the plumbing vent have not been tied in together (non-plumbers think you can do this).
Wet venting is simply a vent that is also used as a drain. However there are rules that go along with wet venting--four fixtures max, 1 and 2 FU fixtures, same floor, increase 1 pipe size, vertical piping only, 2" minimum pipe size...
Deb
The Pipewench

A wet vent is nothing more than a [usually] horizontal drain (as opposed to toilet soil) pipe that runs into another drain pipe that IS properly vented.

It's called "wet" because it shares characteristics of BOTH a drain and a vent along its developed length.

While the allowable length of a wet vent varies (primarily with diameter of the pipe) they are generally no longer than 6' from the fixture drain to the PROPER VENT.

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EVERY fixture MUST have a trap. EVERY trap MUST have a vent.

STRANGE things happen when a drain pipe runs full--air pressures (both positive and negative) build in the system. Venting is there to keep keep these pressures to an absolute minimum. "Wet" venting is a bit of a concession--wet vents are kept SHORT to ensure that any "jump" (the pipe running full) is RAPIDLY abated by the vent CLOSELY downstream.

You can HEAR this happening in a wet vented bathtub--particularly old, deep tubs drained when they are quite full. That rather loud noise is the sound of the pipe "jumping" full and RAPIDLY loosing the ability to run full because of the CLOSE downstream vent.

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You should NEVER smell foul odors from a drain, waste, vent system unless you stick you nose into the vent coming through the roof!

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With UTMOST sincerity (from a hard-core DIYer), please call a plumber!

WET VENTING IS USING ONE VENT FOR A BATH ROOM GROUP.
I TAKE THE VENT UP FROM THE LAV TO TERMINATION. THE TOILET BEING THE MOST UPSTREAM FIXTURE I WILL PLUMB THE LAV NEXT AND THEN TUB DOWN STREAM FROM THAT .
WHAT YOU DO THERE AS THE TOILET PASSES THE LAV WYE THAT IS THE VENT FOR THE TOILET NOW ALSO AND EVERY DOWN STREAM FIXTURE NOW THE WHOLE THREE INCH IS A WET VENT AS LONG AS YOU ARE WITH IN 5 FEET FROM TUB TO 3 INCH PIPE YOU CAN HOOK TUB TO 3 AND IT IS VENTED IF OVER 5 FEET YOU HAVE TO UP SIZE TUB DRAIN ONE SIZE AND THEN YOU CAN GO 8 FEET IF OVER 8 FEET YOU HAVE TO PUT A VENT UP FOR THE TUB BUT MOST BATH ARE WITH IN THE 5 FEET MARK . IF THE TUB WAS ADDED BE FOR THE LAV WITH THE VENT . THE TUB TRAP MAY BE SUCKED BYE TOILET PRESSURE AS IT PASSES .

IM LEANING TO NO TRAP EXHAUST FAN MIGHT DO PULL THE SMELL INTO THE ROOM . JUST A LITTLE NEGATIVE PRESSURE IS ALL IT WILL TAKE

The purpose of venting is NOT to allow odorous gases to escape - it is to allow air to enter behind the draining water. Imagine a small necked bottle filled with water. Invert it - the water doesn't drain -no air can enter. Now punch a hole in the top - that's a dry vent- now the water drains easily. Now do the same, only this time, tip the bottle on it's side. Water drains as air enters the spout above the water - that's a wet vent. In a plumbing wet vent, the pipe must be big enough so that draining water never fills it to the top. If a system has no vents, air will have to come in through the drains, pulling the trap water down the drain with it. The purpose of the trap is to form a water plug to prevent the sewer gases from coming into the room up the drain. In your case, the odor problem is most likely due to the amateur plumber not installing a trap. If this is true, no amount of venting will solve the problem. Check this first. Run a good amount of water into the drain and then immediately (don't run water down any other drains) look into the drain (flashlight) for standing water. No water - probably no trap. If no trap, this MUST BE RECTIFIED or you will have odor no matter what else you do.

Good Luck!

It is possible that there is a trap.I mean to say that there could be the fitting installed and water visible with a flashlight and still get sewer odor.#1,non-existent vent or wrongly located vent.[bummer for you]then you would know why s-traps are no longer used.#2just a question.how do you know it is sewer odor?whilst bathing does one stick ones nose into the drain?not this evil eskimo boy.i have seen an abandoned galvanized water line unleash a nasty smell into one paticular fixture.to assume in plumbing can be expensive hubris.

Question: Other then being a Code requirement, is there a reason why a plumbing system in a building needs at least one vent to the outside of the building? Why not use a sufficient number of Air Admittance valves, and eliminate the traditional vent to the outside? Is there a threat of gas build-up in the pipes that may explode? It is the same situation whether the building is connected to a septic tank or city sewer?

yes, in theory, you could vent an entire home with mechanical vents, but with anything mechanical there comes a time when they will fail. Depending on how a budding plumber was trained....on the job, or in a classroom...you will get differing theory on trapping/venting.

Yes, be it a septic system, or city sewer, the venting should be the same.

Gerry

Problem is occuring when shower is running, anybody consider the hot water heater?!?!?!?!?!?! Don't the hwh's give off a smell when the rod reacts to the water or some SH+*#+t like that?

By the way, being new here I have found lots of info on venting in books. Venting is not for pushing water down a pipe, it is to keep the water in the trap from siphoning off. It equalizes the atmospheric pressure in the pipes to allow the trap water to stay there................

Hi. I've been reading everyone's posts about the proper way to vent plumbing. Is it absolutely necessary to vent a fixture (in my case a kitchen sink drain), within a 5ft radius?