26 votes
Accepted

What is this tube sticking out of my roof?

Almost certainly a vent for plumbing. It connects to the sewer, so it doesn't need a cap. It's highly likely there's a sink or other fixture nearly below it.
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22 votes

Does my toilet drain poorly because of bad venting?

It's a common misconception, but blocked vents do not cause slow drains. If you Google it, you'll find lots of incorrect information that completely ignore the physical realities of how a vent ...
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15 votes
Accepted

Does a plumbing vent need to penetrate the roof? (Can it penetrate a wall?)

No problem, as long as the vent meets the criteria listed below. Not directly below a door, openable window, or other air intake opening (of this or any other building). Not within 10 feet ...
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  • 128k
14 votes

Does my toilet drain poorly because of bad venting?

Unless something is clogged, this should work fine (assuming appropriate slope on all lines.) The vent should be 2" for a 4" line, and is only draining the tub (2DFUs) which is half the ...
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  • 132k
11 votes
Accepted

Persistent sewage smell coming from basement drain

You are correct that floor drains do need to be monitored and occasionally the trap refilled with water. So the first thing to check is that your floor drain actually has a trap. The way to do that ...
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  • 18.7k
11 votes

Is my plan for an air admittance valve ok?

The valve needs to be downstream of the trap, basically in the position an actual vent would be. source Also, be sure they're legal where you are. My local inspector forced me to run a new vent line ...
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  • 104k
10 votes

Why does flushing a downstairs toilet cause an upstairs toilet to also flush?

This is a classic venting problem. If it has NEVER worked right, someone designed something wrong and it's going to be expensive to fix now because it will entail opening up the walls. If it WAS ...
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  • 14.4k
10 votes

What is this tube sticking out of my roof?

It's a vent pipe for the plumbing it connects eventually to the sewer. It will catch a small amount of rain but the rain will stay inside the pipe and eventually reach the sewer. You're probably not ...
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  • 13.2k
9 votes

Sink tailpiece doesn't line up with trap

The photos posted above were really helpful, since many people may not know what connectors and adapters are available -- as I didn't before replacing two vanities. Therefore, I thought I'd post ...
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8 votes
Accepted

Why are loop (Chicago) vents typically built with three elbows?

From the International Association of Plumbing and Mechanical Officials (IAPMO) "Uniform Codes Spotlight" archive from February 2018: The configuration of the return bend using 45 degree and 90 ...
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  • 1,084
7 votes

Why are loop (Chicago) vents typically built with three elbows?

There is no reason you need the three sections vs one 180 degree return piece other than you have copied in one of the oldest and most used plumbing pictures on the internet. I do my own plumbing ...
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  • 46.2k
7 votes
Accepted

How does a plumbing vent work?

Pluming vents do two things - they allow air in and they allow air out. Simple right? The first need of allowing air in can be visualized with a plastic bottle that has a narrow neck, like a soda ...
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  • 26.6k
6 votes

How can I prevent or remedy "bio slime" accumulation in a sink drain?

This has been an ongoing problem in the bathroom sink we use the most. When I was using conventional solutions (Drano and the like) to unclog it, I just assumed that there was a bunch of hair in the ...
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  • 61
6 votes

Sink tailpiece doesn't line up with trap

I had the exact same problem under my bathroom sink. Here's a picture of how I resolved it. The first elbow off the sink is 1.5" because I couldn't find a 1.25" female-to-female elbow in my local Home ...
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  • 12.2k
6 votes

How can I tell if a given roof vent is still active, connected?

One thing you can do regarding the question if it an active part of your plumbing is to turn on your water sources one by one. While water is running down the respective drain put your ear to this ...
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  • 61.1k
6 votes

Does my toilet drain poorly because of bad venting?

Run some water in the tub until the problem shows, then get under there and slap that pipe to see if it's full of water it should be mostly empty and sound hollow. If it's full there's a blockage ...
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  • 13.2k
5 votes

How can I prevent or remedy "bio slime" accumulation in a sink drain?

I attached 12" plus or minus of electrical copper wire to my drain plug. Copper kills the bacteria. I have not had a problem since, and it has been 4 years.
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  • 51
5 votes

How can I hide a sewer 'Candy Cane'?

Cutting it off is a bad idea. Aborting the "process of buying" that you're in might be worth considering if it bothers you that much. Relocating it significantly would probably require significantly ...
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  • 132k
5 votes

Why do I have a vent stack if none of my fixtures are vented?

Depending on the size and age of your home, and the location of the plumbing fixtures. It's entirely possible that there's only a single vent stack. If all the drains are within a certain distance of ...
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  • 128k
5 votes
Accepted

Why do I have a vent stack if none of my fixtures are vented?

Your system is almost certainly vented. Plumbing vents provide a path for sewer gases to escape so they don't bubble up through the P traps into your house under pressure (the sewer gases will expand ...
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  • 5,686
5 votes
Accepted

Is PVC an acceptable pipe for a vent stack through the roof

National (international) plumbing codes identify vent pipe size, length above the roof, flashing and caps. But does not specify material. PVC, ABS and galvanized have all been used. You are right ...
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  • 1,058
5 votes
Accepted

Can a plumbing vent go up a different drain, for some length

Your concerns are valid: The provided sketch would not pass any plumbing code that I am aware of. It indicates a vent from a separately vented fixture connecting to the drain portion of another ...
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  • 4,272
5 votes

Is there any filter or material that let only water through not dirt

You can get "drain tile sock" or drain tiles with "sock" installed at just about any place that sells building materials. These are used where you want to allow the water to pass ...
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  • 20.3k
4 votes
Accepted

Vent below window

Other codes may vary, but according to the 2012 International Residential and International Plumbing Code: P3103.5 Location of vent terminal. An open vent terminal from a drainage system shall ...
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  • 6,825
4 votes

How can I stop this drain pipe from backing up?

The plumber you had out kind of left you hanging. He should have put a camera down there to give you more details on what is going on. Basically your septic tank is backing up or you have an ...
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  • 46.2k
4 votes

Does a plumbing vent need to penetrate the roof? (Can it penetrate a wall?)

Or, don't vent externally at all. In many jurisdictions you have the option of an AAV - Air Admittance Valve, readily installed in a wall box behind the washer. An AAV involves a gravity seal that ...
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  • 10.3k
4 votes
Accepted

How to plumb a washing machine 30 ft from the waste stack?

1/4" per foot of slope is generally considered the minimum slope, so as long as you have a bit over 7" to work with vertically, you should be able to slope the drain over 30' just fine. You'd set up ...
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  • 23.8k
4 votes
Accepted

combo tee vs. tee wye

The combo tee has a longer sweep. Long sweeps are easier to run a snake through and drain better as the water path is gradually changed (if you have the space to use them). 45 wye Combination wye &...
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  • 95.4k
4 votes

How do I eliminate stink from a waste water pipe?

Cut the current pipe and install the p-trap near the bottom, close to however it's vented. Retain the cut piece of pipe and add it back above the new p-trap. Gluing to the top (as mentioned in ...
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  • 4,140
4 votes
Accepted

What is the correct height of a toilet flange relative to the finished floor?

The original intent of the toilet flange is to screw down to the finished flooring, not below it, definitely not shimmed up above the finish floor, although there is a small bit of room if there is a ...
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  • 31.1k

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