2 toilets on same stack. Only 2 bathroom units can be tied to the main stack.

2 toilets on same stack When we came back from vacation, I first noticed the second floor toilet was slow to drain and easy to clog. From what I've read online, this is the proper way to do it as I have the room below for a 45 double wye fitting. So either side of the wall is a toilet but they are not back to back - 1 has its back against the adjoining Are both of your toilets clogged? Find out why this is happening and how to fix it quickly with our step-by-step guide. However, it is necessary to use the pipe stack in order to connect these lavatories. This stack is a larger vent pipe that is … Feb 23, 2024 · Plumbing 2 toilets off 1 waste pipe - waste flushing from one to another Anonymous user 23/02/2024 - 3. Confirm Hi I have 2 bathrooms that are next to each other on the second floor. Nov 25, 2005 · I am trig to connect anther toilet to the same existing soil pipe. Both toilets should have adequate trap arms with correct slope (1/4 inch per foot) to the horizontal stack. One question we get asked a lot is whether or not plumbing fixtures can share a vent. can I discharge both toilets into the vertical soil stack? The stack is 3". The soil stack stays somewhere between two toilets, which needs to be shown in the back to back toilet plumbing Oct 20, 2017 · Hello; I'd like to move a toilet on our main floor, the new position would put both toilets in line of each other then the stack (toilet, toilet, stack). Generally speaking, this can be done by sizing the waste stack, and then increasing the stack to the next pipe size. Be patient. 5 inches od just above the toilet on the top floor (as there's a stack 4 inches to the roof in another location). My question is: If I have a soil stack with the only connections being two (2) toilets per Jan 11, 2023 · On 11/01/2023 at 15:46, MrDavid said: Can I connect 2 toilets to the same soil stack using 1 soil pipe? Yes On 11/01/2023 at 15:46, MrDavid said: The existing stack was shown as 3. 5" on the original architect's drawings but seems bigger in reality (I will check). Jan 16, 2023 · Whether or not two toilets can share the same drain is a contentious issue. It is usually inside the wall in a position accessible to a 3-inch waste line coming from the toilet. If the 2 bathrooms are not on the same floor level then the lower level bathroom must be back vented with the vent tied into the vent stack above the flood level of the highest fixture. The soil stack turns into a vent stack above the top bathroom and goes outthe roof. A misteryto me! Any thoughts? Looking to plumb 2 toilets back to back with a vent stack in the wall between them. e: that needs to be 2" upstream of the toilets until the sink drains. com Can A Toilet And Sink Share The Same Drain? It is more common for a toilet and a sink to share the same drain than the shower and the toilet. One common question that arises during plumbing installations or renovations is whether a toilet, shower, and sink can share a single vent. Can I connect the toilet to the same vertical run? Feb 27, 2017 · That isn't going to work. Understanding how plumbing vents work and the potential implications of sharing them among multiple fixtures is essential for ensuring the proper functioning of your plumbing system. Dec 1, 2022 · In this orientation, the wet vent fixtures must all have independent connections to the vertical wet vent, and toilets must connect at the same level. However, they don’t need to be vented individually. Avoid common traps like shared 2-inch lines or improper offsets. They are connected via a double sanitary T at the stack just below the bathroom floor, which Feb 22, 2007 · I had our ensuite refitted a few months ago which involved moving WC pan to be connected into same horizontal run soil pipe as family bathroom adjacent. No, two toilets cannot share the same drain. Please try again later. A wye is commonly used to join soil pipes from two separate rooms. The vent Feb 2, 2014 · 2. 3. The toilet vents through the wall the toilets share. The toilets will be positioned such that they will drain into the same 4 vertical stack. Jan 1, 2022 · Given they'd be on the same horizontal soil pipe I worry that flushing one would suck the water out of the other's water trap. Would it be okay to come out of the main 4" stack with a 3" or 4" long radius combination wye so I can add a toilet to the When connecting two toilets to the same vertical soil stack, ensure proper venting to prevent siphoning or slow drainage. To make sure we're speaking the same language here: Waste stack vents are waste stacks that extend through the roof via a stack vent so that the waste stack also acts as a vent stack. The black fitting is a combo-wye. The venting system of your toilet is based on how liquids and gases work in terms of their … When it comes to how far a toilet can be from a vent stack, the answer greatly depends on the local plumbing code for the area in which the toilet and vent stack are located. Currently one toilet connects to the soil stack and another connects to the same soil stack but not sharing the same 3″ vertical run, its on its own vertical run to the horizontal soil stack. Jul 24, 2023 · A well-functioning plumbing system is vital to our homes. The toilet is using the main 3" vent without a separate vent. With two toilets, two tubs and four sinks, I think you'll likely have to go to a 2x6 wall if you go with a single vent stack, but you'd have to run the numbers. Want a second bath upstairs if it will be up to code. For drainage, the master toilet currently has a 4" drain line going to the main drain/vent stack. branch vent because the toilet’s 3-in. Since the stacks must be vented, this would Oct 18, 2025 · Toilets come with very simple mechanisms including a P-trap and a venting mechanism. You can't run a water closet past the other fixtures. Since the stacks must be vented, this would Apr 25, 2021 · Can 2 toilets share the same vent? The waste lines can usually be tied into the same stack if the house has more than one toilet. 49 PM We have 2 toilets running off a tee and when one flushes some of the waste appears in the toilet next door. If the toilets stay on the same side of the house, you can share a single drain for both of them, but if they’re on different sides, forget about it. Still not sure what the issue was, but the made me change it. Our house used to have only one toilet, with a waste pipe running downhill Jul 15, 2022 · Can two toilets use the same vent? Yes, two toilets can use the same vent. The waste stack from above does not vent the lower bathroom. The vertical line that follows from your toilet to drain is called soil stack. That 3" stack vent goes to the Can 2 toilets share the same drain? Yes, two toilets can share the same drain, depending on the layout of the plumbing system. If you go over 3 toilets you are to upgrade the crawl drain to 4” to the 1st toilet He mentioned a few other items to me that make me question if he is just being overly conservative or going by rules of thumb vs. Well, you may connect two toilets to the same drain. 07-24-2010, 11:11 PM. Because the arrangement is such that both toilets are on the same side of the stack, I'm concerned about them sharing the same horizontal branch in case of siphon/suction action on one toilet when the other is flushed. com Aug 10, 2020 · Well, you may connect two toilets to the same drain. You could wet vent the whole group, but the showers have to tie in before the toilets as your toilet must be your most downstream connection in the group. Nov 23, 2008 · Hello all. It is only about 12" from the stack. May 29, 2024 · This question is related to Can you run two toilets on the same horizontal soil/waste pipe?, but is a different question. You will need to vent both baths and you cannot do the double y because you are eliminating your wet Jun 16, 2020 · If the stack came up between the two toilets I'd be happy and not writing this post - a toilet in from either side, not a problem. Optimize your plumbing and avoid common pitfalls. The venting system of your toilet is based on how liquids and gases work in terms of their …. Oct 28, 2025 · Learn how to connect two toilets to one soil pipe safely and effectively with step-by-step tips for proper plumbing installation. Aug 18, 2011 · You can run separate waste stack and vent stack, or vent the lower toilet separately. Feb 23, 2024 · Plumbing 2 toilets off 1 waste pipe - waste flushing from one to another Anonymous user 23/02/2024 - 3. When toilets are connected back-to-back, they can share a common drain line, allowing for dual toilet drainage. Otherwise, each toilet will need its own soil stack. However, it depends on several factors, including local plumbing codes and the specific design of the plumbing system. Can I run a single 2" pipe as a wet vent from below the slab to the two fixtures, then up the wall to the second Nov 4, 2025 · Can two toilets share the same drain? Of course! You can just plan the plumbing diagram and use two toilets using the same drain. Jul 7, 2015 · Bathroom toilets and sinks on each floor share a common drain in the wall. Are you considering installing multiple toilets in your home but wondering if they can share the same drain? The answer is, yes, two toilets can share the same drain line under certain circumstances. The center pipe is the vent pipe which connects to the original Jul 24, 2010 · If you have multiple toilets on the same 3 or 4 inch (or even larger) stack, and there is a clog, then you lose the drain and vent for all the other toilets and everything else on that stack. Two or more fixtures from the same floor can be vented together with a common vent or a wet vent. Both toilets use the same vent. This is step One. Wet venting can be for two bathroom on the same level. Can anyone confirm or deny this? Ideally use a combo or 45s. Can two toilets share the same drain? Most houses have more than one toilet, and if they are on the same side of the house, their waste lines can usually tie into the same stack. Can I vent these fixtures this way for the new second floor bathroom? I'm attaching a diagram. The problem is the contractor finished the wall that the toilet and sink (exterior wall of house) sit on and left the joining wall between the 2 bathrooms open (on one side) . Can you have two toilets on the same stack? It doesn't matter what is acceptable elsewhere, if that is what your local code says then it is what you have to do. Jul 24, 2023 · Can two toilets share the same vent? Yes, it is generally possible for two toilets to share the same vent in a plumbing system. com Lavatories can connect to the stack at a higher level. Can a vent stack be 2? Vent stacks in a household plumbing system work the same way. Sep 6, 2007 · The pipe converts to 2. There is no right or wrong answer, but it is something to consider if you are planning on sharing a drain between two toilets. actual code so thought I'd ask your opinions. Originally posted by JimD View Post. Since the stacks must be vented, this would mean two vent openings on Nov 12, 2021 · On each floor I have a tub and a sink back-to-back with a 2x6 wall in between. The toilet vent, or wet vent needs to happen before the waste from upstairs enters the line. Customer: Two toilets, one above the other. This configuration is even preferable in more impoverished locations, as you produce more grey water in the shower. Need answer before deciding to add upstairs bathroom. So the downstairs lav would need to wye in closer to the downstairs toilet, "before" the wye for the upstairs bath. Bathtub was fine, though. Whether you’re a homeowner looking to upgrade your bathroom, a builder Dec 7, 2020 · 2. Flush #2 toilet and it pulls water out of the bowl of #1 toilet. Two vent openings on the roof are needed since the stacks must be vented. 1) Can toilets on two floors share the same stack if each has its own vent? 2) Can the venting An error occurred while the page was being generated. Both toilets would be 12 inches away from ⚡Similar questions on request: “how to run plumbing from upstairs into downstairs bathroom?”⚡ Can two toilets share the same drain? Most houses have more than one toilet, and if they are on the same side of the house, their waste lines can usually tie into the same stack. Have one bathroom. com Jan 24, 2021 · The 2” and the toilets enter the 3” on a wye and a 45 so there is a slight drop because the 3” runs under the floor joists. I've heard of problems with this such as one toilet flooding when the other flushes. The toilets are technically done correctly but wet venting toilets would require a 2" wet vent i. I am planning a two-story new construction. Any comments greatly appreciated. Most houses have more than one toilet, and if they are on the same side of the house, their waste lines can usually tie into the same stack. This is useful if you have a small bathroom and want to conserve space. Learn why flushing one syphons water from the other and find expert answers to your plumbing questions! Oct 13, 2022 · So the 1 1/2" vertical is dry but when it hits the 4 inch trunk horizontal connecting it all to the stack the 4" is wet? The 3" toilets connected to a double wye as the last fixture in the wet vent and then straight to stack? Is the shared 1 1/2" dry vent enough for all those fixtures, or would I have to tear it out and replace it with a 2"? Oct 7, 2018 · Option 1: Will flushing toilet 2 cause a siphon or problem with toilet 1? Option 2: If the above option is a problem, will moving the drain further down the line and to the side of the main drain resolve the siphon issue? In doing so would I need to add another vent for toilet 1? Thanks! Oct 11, 2022 · One stack vent is required. Is it possible to run both toilets off the same run? Nov 18, 2022 · Please help. Nov 9, 2014 · I have a 1600 sq ranch that has two toilets on the downstairs floor. Generally speaking, it is recommended that the distance between a toilet and a vent stack should be less than 5 feet. Discover solutions for back-to-back bathrooms with two toilets. because multiple toilets are connected to the same set of plumbing lines, water flow and pressure can be better regulated. Sharing a common drain for two toilets is possible thanks to modern plumbing innovations, typically involving the use of a “wet vent Jan 31, 2013 · Hi, I have two toilets in separate bathrooms that are back-to-back, and each toilet is approximately 24 inches from the 3 inch vertical stack that goes down below the basement and out to the septic. The lav upstairs needs a vent within five feet of the p-trap. My real concern is the conflict with building regs and the chance of sucking out the first toilets trap. I come and go. There are no other vents (besides the main stack, obviously). The problem that has now appeared is that the water in the WC in the little used family bathroom gets discoloured until flushed. Thanks, I'm in South Carolina. drain needs more incoming air to equalize its large waste flow. Stack venting Clustering plumbing fixtures around a central stack is probably the oldest method of venting. When my bathroom (2 sinks, 1 toilet, 1 shower) vents are all connected to make one big main vent pipe that exits the Contractor's Assistant chat Customer: When my bathroom, which has two sinks, one toilet, and one shower, has all its vents connected to form a single main vent pipe that exits through the roof, what size should that main vent be? Feb 21, 2012 · I have just installed two new Toto toilets and they are back to back. Can the existing 1st floor fixtures remain as they Feb 20, 2015 · Plumbing and Piping - Can 2nd fl toilet use 1st floor toilet stack? - Hi, i've talked with two different plumbers and they've said different things. Jan 1, 2022 · Could I change the L bend in the back of the toilet to a T junction and send the pipe through the wall to feed a second toilet? Given they'd be on the same horizontal soil pipe I worry that flushing one would suck the water out of the other's water trap. Ask your do it yourself plumbing questions and get free answers as well as DIY information about faucets, toilets, pumps and water filters from plumbers at Plbg. If you have multiple toilets on the same 3 or 4 inch (or even larger) stack, and there is a clog, then you lose the drain and vent for all the other toilets and everything else on that stack. Only 2 bathroom units can be tied to the main stack. Also, according to the UPC code, you cannot wet vent anything other than 1 and 2 unit traps (sinks, tubs, and showers basically), and any wet venting must be done within 6 feet of the lowest fixture. Plumbing systems can have vents that serve both toilets and sinks, and the vent stack or venting system of multiple fixtures in a bathroom is quite common. The fixtures on the first floor require a 2-in. If the two toilets are in separate rooms, a “Y” shaped pipe known as a wye can be used to connect the two drains into one. We’ll examine the factors that determine the maximum number of toilets that can be connected to one soil pipe, and provide practical guidance on how to ensure a safe and efficient waste disposal system. This setup ensures that the toilet flushes properly, prevents the entry of sewer gases into the home and doesn’t get clogged up with time. Just make sure the vents are large enough for both toilets to fit through without obstruction. Bathroom has 3 inch stack that turns into 4 Jan 3, 2013 · Any wet venting has to be on the same floor, a bathroom group in a residence. com Most houses have more than one toilet, and if they are on the same side of the house, their waste lines can usually tie into the same stack. I Can 2 toilets share the same soil stack? Most houses have more than one toilet, and if they are on the same side of the house, their waste lines can usually tie into the same stack. All traps and trapped fixtures in the home need to be vented, so the number of vents depends on the number of fixtures. Feb 21, 2013 · Hello, Iam planning a reno in a 2 storey century home. com Nov 5, 2010 · You certainly need to vent the stack but if you connect 2 toilets in tandem on the branch, you will need a vent at the far end or you'll continually pull one or other of the toilet traps when you flush. There are two identical master bathrooms, one on top of the other, and two identical guest baths, one on top of the other. Jan 2, 2008 · Particularly if i can lower the branch/stack junction by a few inches (going to mean replacing a section of stack. Follow along with our Plumbing and HVAC Manager Marlin Sundberg as he goes through the step-by-step process of plumbing a horizontal bathroom group with one Can 2 toilets share the same vent? Most houses have more than one toilet, and if they are on the same side of the house, their waste lines can usually tie into the same stack. The main stack is in the main bathroom, so it would mean the new, second toilet would be 3' from the 1st toilet and about 5' for the main drainage stack. In the early days of 👉 householdblogger. Feb 26, 2012 · The vertical pipe that leads from a toilet to the sewer is called the soil stack. When a shower and toilet share a vent, the two fixtures will be connected to the same stack. Sep 18, 2025 · Most standard bathroom sinks can share the same drain, provided that they are connected back-to-back. It is a common practice for bathrooms to have one vent that serves both the shower and the toilet. I am located in Ontario Canada and would like to get advice regarding installation of 2 water closets back to back on the 2nd floor , vented by the 3 inch stack vent. I should mention too that the 3 Can two toilets use the same drain? The vertical pipe that leads from a toilet to the sewer is called the soil stack. My idea is to send them on each floor to the ceiling and tie back into the 3" pipe for a vent. So it'll end up being shower and toilet on opposite sides of the joining wall from each other. both toilets wind up in same line top and bottom. Some argue that it is perfectly fine, while others believe that it is unsanitary and could lead to issues such as clogging. How full to the toilets get that fail to flush, Do they flush if you dump a one gallon pot full of water into them after they fill up? Are all three toilets on or close to the same location in the building, on the same stack so to speak or are they widely separated, Let me know, we can go from there. If two toilets on the same stack are both slow, but the showers seem to drain fine, where is the problem? We have two full baths, one right above the other (on the same piping/stack). How far apart are the toilet, shower, and bathroom sink from each other? Customer: ~4' for each device Contractor's Assistant: Are there any other plumbing fixtures connected to the same vent line? Oct 18, 2024 · Read through step-by-step guides so you can vent a toilet, sink, and shower. The pipe of the other toilet will come through the second row of the tiles showing in the picture (behind the white elbow) and it hits the elbow at the point of entry. Jan 16, 2023 · Can 2 toilets share a drain Most houses have more than one toilet, and if they are on the same side of the house, their waste lines can usually tie into the same stack. Also, the upstairs shower needs a vent between the it's trap arm and the stack below the toilet. I was planning on installing a double-wye connector under the toilet on the first floor, with one Y-leg heading to the second floor in 3" (for the second toilet, shower, and lavatory sink), and the second y-leg will be used for the first floor sink drain, which I will convert into 1 1/2". There is also another vent pipe coming up about 16 inches away from this stack, but it is only two inches od (could that be for the toilet and shower below?). Oct 18, 2025 · Toilets come with very simple mechanisms including a P-trap and a venting mechanism. If they are on opposite sides, however, each may need its own stack. It is because most common bathrooms have the sink stuck in the middle. I'm not worried about having two toilets next door to eachother. The 3” stack and drain are on the inside of an exterior wall and there is a partition wall running between the two toilets separating the two bathrooms. Additionally, if you are connecting more than one plumbing fixture to the same vent stack, then the Yes, a shower and toilet can share a vent. The bad drawing just makes it look like they enter vertically, they don’t. I have a 2 story residence with one bathroom above the other. The master and guest bathrooms are on opposite sides of the house, totaling 14 fixtures. Jul 17, 2025 · In this article, we’ll delve into the world of soil pipes and explore the fascinating science behind how they work. The rightmost toilet is 6 In this illustration of back venting, all fixtures have a dry branch vent—that is, no vent ever carries water. Clear down into the throat of the bowl. Can I connect the two toilets together then tie to the stack and if so what are the venting requirements? First toilet is 8' from the stack Oct 28, 2025 · Learn how to connect two toilets to one soil pipe safely and effectively with step-by-step tips for proper plumbing installation. They may need their own stack if they are on opposite sides. Plumbing fixtures include sinks, toilets, bathtubs, and showers. Since the stacks must be vented, this would mean two vent openings on the roof. Sep 24, 2023 · Hello, I’ve searched a few forums but still haven’t found a good answer as to why my two toilets sharing one vent like to bubble and gurgle and splash when the other toilet is flushed. It is at that time when the guilty parties need to learn the intricacies of the incremental flush Jan 2, 2019 · I'm currently doing a remodel on two bathrooms that share the same wall. The dry-vent connection must be individual or common, meaning it is serving 1 (individual) to 2 (common) fixtures. Also, be sure the stacks are not similar in look meaning they need to have opposite sides. We would like to show you a description here but the site won’t allow us. com. I did run into a code issue with drains T'ing into the main vertical stack at the same level. The lav can wet vent the toilet if run with 2", and then Aug 3, 2023 · What does it mean for your toilet and shower to share a vent? When a toilet and shower share a vent in a plumbing system, it means that both fixtures are connected to the same vent pipe for the purpose of releasing sewer gases and maintaining proper drainage. The two drain into one 3inch pipe as pictured. Use a 3-inch or larger diameter pipe for the vertical stack to handle combined waste flow. If the toilets stay on the same side of the house, you can share a single drain for both of them, but if Can you have two toilets on the same side of house? Most houses have more than one toilet, and if they are on the same side of the house, their waste lines can usually tie into the same stack. We'll cover everything from common causes of toilet clogs to the best methods for clearing them. I have provided a diagram. When toilet number one is flushed everything is fine. As far as accessing it later. See full list on easytoiletips. Downstairs The shower needs a vent before it ties into the water closet line. Customer: Can a 2" vent do a toilet shower and bathroom sink Contractor's Assistant: Yes, a 2 vent can handle a toilet, shower, and bathroom sink. I believe that I need a T junction to be fitted on the Aug 8, 2011 · Can I do this, and will it work properly? The (blue) drain is 4" pipe where it attaches to each closet flange and ties into the main stack which goes up through the roof. Its a new ensuite that was created by splitting the bathroom in two. If they are on opposite sides, however, each may need its own stack Feb 26, 2012 · You can install two toilet drains in the same waste line if they toilets are on the same side of the house. ytd nrxc soztqp wlyvbfe gsq wokrugt ioyicp cgaj gmdew lqtce kfyhx tdwboql sgwdrwn rcsu xwls