Plumbing Vent Piping Tips

31 responses

  1. M. Dugally
    August 31, 2012

    Tim, we are having our bathroom remodeled. The plumber put in the tub and shower pipes but did not allow for enough distance for the fixtures to go on after tile was put on the walls.
    Does this mean a tear out of the tile or wall behind the tub wall? Is there a possible fix without this extreme measure?

    • Tim Carter
      January 6, 2013

      your question requires lots of typing, plus I have some questions for you so I can give you the correct answer(s). I only do pithy answers here in the comment section. If you want to protect the investment you have in your house and not waste time or money *hoping* you make the right decision, you should talk to me on the phone for just 15 minutes. It'll be the best investment you've ever made in your home!

  2. Jim
    November 19, 2012

    I am making a flat roof (deck patio) over an area where there is a black plumbing vent pipe. I woud prefer to cut it to size below the roof deck, put a 45 degree elbow on it and run the pipe out of the side of the building. Are there any issues with that?

    • Tim Carter
      January 6, 2013

      Jim, your question require lots of typing and I have some questions for you. You should consider investing in a 15-Minute Consult with me. Look at my cart for that. Lot's to discuss. I just do short pithy answers here.

  3. Dave
    August 2, 2013

    A Wet Vent System is allowed per code in GA, but do you think a properly installed wet vent system is acceptable or good? Thanks.

  4. Barry
    July 1, 2014

    Tim I have a shed and was wondering if I can vent a sink out of the side wall instead of the roof.

    • Tim Carter
      July 5, 2014

      You can run a vent pipe out a side wall. But you should have asked me if "I, Tim Carter" would do it. The answer is I'd NEVER personally run a vent pipe out of a wall. Always out of a roof. But you can do what you want.

  5. Jason wallen
    November 18, 2014

    Hi Tim, I am a electrician by trade ,but a okunber I am not, I however am tackling my "whole" home remodel. I have a 4 inch septic drain from my basement wall the old plumbing was just a simple 3" vent from the main 4" drain as all fixtures drained here only one vent was used. I have upgraded to two full baths from one and redone my roof . I moved the 3 " stack farther up the roof line and some 4 feet over ,now preventing a straight run from septic exit to roof. My question is ,can my 3 inch vent pipe have any vertical runs. I would have one under the floor joices and another below roof to accomplish a connection from septic exit to roof exir , and all fixtures connecting along the way? Please help

    • Tim Carter
      November 19, 2014

      I think you mean can the vent pipe be "horizontal", right? If that's what you mean, the answer is Yes. But, all horizontal runs MUST HAVE a pitch so condensation water in the vent pipe DRAINS to the sewer or septic. Water can't collect in a vent pipe as it could eventually choke it off from the atmospheric air at the roof.

  6. Jossy
    December 1, 2014

    I have a question my bathroom stall is.not.going down quickly im not sure why. It seriosuly ramndomly happened yesterday nd now my bathtub isnt going down quick enough either. any tips? Someone told me use peroxide but I have no.idea how to even use that

    • Tim Carter
      December 3, 2014

      Maybe there's a hair clog. That's the most common reason a shower or tub drains slowly. Don't pour peroxide down the drain, that's a waste of money. Just get the hair out.

  7. CHAD
    January 6, 2015


    I have just had a home built in the late 60's gutted and remodeled. Against my better judgement I allowed the plumber to connect the new abs plumbing system (drain and venting) to the existing copper vent stack(s) to avoid working on the new roof that had been installed just prior to me puchasing the home. Now that the work is complete and the walls are all closed up I have an intermittent howling noise that have narrowed down to be originating from the area of one of the vent stacks in the house. All of the online info I can find describes a problem that sounds like mine however the cite the cause to be a clogged or backed up drain. As I mentioned all the plumbing is new so that is not the case. Is there anything else that could be causing the noise?

    • Tim Carter
      January 8, 2015

      I'd need more information to help you. This is phone call stuff, not back and forth in comments. I offer this MONEY-BACK Guarantee product.

  8. jason bryan
    January 9, 2015

    I have a vent pipe that suddenly had water start coming out of it and when this happened one of my toilets will not flush. Can you help me with this?

    • Tim Carter
      January 10, 2015

      Yes, I'd have to come to your home. I've never seen water shoot up from a rooftop vent pipe like a fountain and absolutely would love to see this!

  9. Boysie Brown
    February 26, 2015

    Hi I've got a problem with my drain pipe in the wash room when the water spins out of the washing machine and go down the drain it gets full and come back up. Well I tried using Drano liquid 3 bottles still nothing happened, a snake line was used to see was any blockage nothing happened, I even used a pressure hose but nothing happened the water still came back up. Do you have any helpful tips to use?

    • David Beaudry
      June 24, 2015

      I had a similar problem with the washer over flowing where it goes into the pipe. Before you do anything else there is a vent pipe like the one in the picture above. I'd recommend going in the attic and locating where the vent pipe goes. Buy a snake long enough to reach where the vent starts at the washer drain and go on the roof and snake the vent. After some time fighting this and calling plumbers, this was my issue.

  10. Rob
    February 27, 2015

    Hi, I'm actually curious like Boysie. I'm having the same issue. I thought maybe it was the septic, but no other issues reported in the house (its been about a week). Coincidentally, this happened on one of the coldest mornings of the year (in IL). I thought maybe the vent pipe had ice formed, but could not see anything. Other vent pipes a few days later, I had noticed had ice formed on the cap early in the AM, but were not longer visible later in the day - no problems with showers, toilets, etc, only the washing machine.

  11. chuck
    April 22, 2015

    im remodeling a bathroom... the house is located in so. cal built 1955.... the old, galvenized vent pipe to the sink is 1 1/2 inches in diameter.It is wet vented with the toliet and pops out the roof transitioning to a 2 inch pipe along the wy.. At the tee (where the trap will protrude to the sink) the pipe transitions to a 2 inch drain pipe, that flows into a 3inch main line.. Question: I already cut off a section of old vent pipe, near the sink and transitioned to abs. replacing a santee and several feet of pipe also with abs before tying back into the old cast iron stuff. i did this as the old 60 year galvy and cast iron stuff was choked full of debris. Here is my concern/thought. A woman or possible two will be sharing that bath, (roommates) and i was thinking of coming out of the wall, at the sink. with a 2 inch trap as opposed to an 1 1/2 inch. but i will still have to reduce from 2 inch to 1 1/4 to feed up and connect the sink. The other alternative is to come out of the wall with a tee 2x2 x1 1/2 then kick the 1 1/2 down to a 1 1/4 again to get up to the sink.
    my thinking was a bigger trap, the horizontal point would less likely plug up but i've also read that a bigger trap holds more water which might prove harder to push down the line causing a stinkin sink. would either one or the other be advantagous or is it just 6 one way 1/2 a dozen the other?

  12. chuck
    April 22, 2015

    Follow up question: can i reduce the vertical section of pipe coming up from the trap to the the sink opening, (where the pop up will sit),from either 2 or or 1 1/2 to 1 1/4 inches, the latter, which seems to be the standard vertical size pipe i normally see,(in least in older homes) running from the sink hole into the trap?, (see above question) . As i mentioned there will most likely be 2 females shairing this bath which means a lot more hair into the pipes and im trying to do some advance planning.

  13. Tom
    July 10, 2015

    Here is the scenario: Recent heavy rains (flooding nearby), Main drain overflows, No noises prior to over flow and it is draining - extremely slow,I had the main line snaked by plumbers & they went 120 ft out & couldn't get it ; the city guy came out and said the line is 100 ft & their end is clear. I'm thinking that either the city guy didn't actually check or the vent maybe clogged. your thoughts?

  14. Joe
    July 10, 2015

    Hi Tim,

    I'm not sure how or why, but I have a leak in a vent in the attic. The vent is venting the washing machine and runs about 10-15 feet with an upward pitch to the vent for a bathroom. The leak is in the 90 as it runs to a T that connects it to the "main vent". I can fix the leaking joint, but I can't figure out how water could be "climbing" it's way up a vent pipe, and enough to drip out and even cause minor ceiling damage???

  15. Josh
    August 25, 2015

    Hi i am trying to hook the water line to my refridgerator but there is a 1/2 in. pipe with a cap i am having trouble removing. Does anyone have any suggestions? Ive tried twisting and twisting and twisting and pulling but it just wont budge need help please!

  16. Tim C.
    November 17, 2015

    Hi there,

    I purchased a 1950's ranch last year. It's on a new septic system. We did a full bathroom remodel and put in all new plumbing including the vent pipe. We did a 4" PVC pipe. Now tied to this is the 1 bathroom (sink, toilet and shower), kitchen sink, and in the basement, on a pump is the slop sink and washing machine (which is older and uses a LOT of water). Well recently the smell of the septic seemed to have been getting worse outside in the yard. I purchased a filter to go over the vent pipe - nearly immediately the smell was gone and I was happy about that. But within hours, the septic sewer smell showed up in my bathroom.

    I went on the roof an removed the filter on top and the smell in my bathroom went away.

    Also at times, I will smell a little bit of the septic smell in my basement, more specifically the drain on the slop sink and/or the washing machine...almost like a bit of gas is coming back in. I can't nail it down...Any ideas?

    Thanks in advance...

  17. Isaac Hicks
    December 28, 2015

    Hey Tim, I own a home built in 1957, a townhouse that for the life of me I can not find a vent line. I was told by a friend who's a master plumber that the main stack vents everything which is cool I guess except I want to put a bathroom in my basement and I am struggling with finding out how to do exactly that. everything drains into the basement floor via this stack. The system I am installing would be an upflush system that I know would need to be vented, but where would I vent it to? I've found my main stack, unsure where to connect the vent, could i tie it into the same stack above where i tied in the slurry from the upflush?

    • Tim Carter
      December 29, 2015

      I'm a master plumber among other things. I developed a product years ago for this situation - I call you on the phone to guide you through the situation. You'll need 30 minutes. CLICK HERE to place the order. MONEY-BACK GUARANTEE if you don't feel I helped you.

  18. Joan Irene Geiger
    August 6, 2016

    I'm having a bathroom remodeling done. I'm 82 yrs. old...while the plumber was putting in my new in-wall medicine cabinet he ran into a vent pipe - black about 3 in. or more in diameter in the area the cabinet was to be installed. He said no problem..he would offset the pipe around the area to make it fit. Well I got to thinking about this and since it is a small job no permit was gotten! He cut the pipe, fixed it...never saw the results on what was done, he put the cabinet in, and now I'm worried about the off-shoot angle and whether it will collect condensation, or not vent properly...besides I don't know whether this is venting the toilet or just a vent? What should I do, this project has had so many complications from the flooring to the painting, etc.

    • Charles Davis
      October 24, 2016

      As long as the plumbing isn't making noise and it operates correctly, I wouldn't worry about it. Its to late to see the work. Maybe you could ask the plumber how he vented the pipes. You wouldn't get any condensation unless the pipes were installed level without the proper pitch. Hope this helps. Hopefully the Plumber followed your local city Code for plumbing installation.

  19. Charles Davis
    October 24, 2016

    Dropped a piece of 3in PVC pipe into the 4" Galvanized main drain stack, while replacing faulty piping. The PVC pipe is about a foot in length and is wedged in the main drain stack at least a foot down. How can I remove this? Will it eventually clog the drain, if not removed?

  20. Chuck
    February 10, 2017

    I am installing a sewage ejector pump in my basement. I have everything laid out with the exception of the vent. I do not have the ability to run a vent to the roof and don't want to go out through the wall since it would be on the front of the house. I had a buddy who is a plumber look at it and he told me I can vent back to a vertical section of the main line which eventually does go out through the roof. My concern is he said use a sanitary T upside down which I agree would be okay if I did't have two bathrooms above it. I feel using a regular t would be a better option to avoid any discharge from the floors above entering the vent line to the sump. Am I wrong for thinking this?

    • Tim Carter
      February 10, 2017

      I'm a master plumber. You MUST do whatever is necessary to get a full-sized 3-inch vent from the ejector pit to the roof. PERIOD. No exceptions. I'm certain if I visited the job site I'd be able to make it happen.

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