A: all wet vents must connect to a dry vent. B: without a diagram and details about what is already draining and venting into these pipes, and their sizes, and the proposed pipes, there’s no way to answer this question.

Can you wet vent a sink?


Quote from Youtube video: So the section of the vent pipe that is going to be used for the drain is where the wet vent is going to be used as the drainage. Water from the sink enters into the vent for the toilet.

What happens if a sink doesn’t have a vent?





Without venting, the negative pressure caused by the flow of draining water can potentially suck water out of the drain trap and allow sewer gases to enter the home. The vents allow air into the drain pipes to help keep the drain flowing properly.

Does a sink need its own vent?

A plumbing fixture like a sink can not function properly without a sink vent. When a drain pipe drains it creates a negative pressure in the sink drain; the negative pressure will pull the water out of the p-trap of the sink that’s draining and sewer gases can enter your home if a sink vent is not installed.

Does every plumbing drain need a vent?

Without getting too far into building science, a general plumbing rule of thumb is that every drain needs a trap, and every trap needs a vent. All those traps and drains are designed to prevent sewer gas from entering your home.

Does plumbing vent go before or after trap?

The simple answer is if your trap from the fixture cannot see the vent then it is installed wrong. We must always keep the vent connection above the trap weir to prevent siphoning and keep proper pressures on both side of the trap.

Do plumbing vents have to go through the roof?





It does not have to go through the roof. From the plumbing code (I have the 2003 edition), P3103: It must not be less than 4 feet directly beneath a door, openable window or other air intake of the building or adjacent building.

Can you put an elbow in a vent pipe?

Note: You may have vent piping, but you still cannot use the tight 90-degree elbow — sometimes called a “vent elbow” — if the joint is below the water level, which is usually at the level of the sink.

How many vents do you need for plumbing?

At least one main vent stack is required for every building that has plumbing when connecting separately to the sewer for the building or its septic tank. The stack has to run the most direct route through open air or be ventilated to extend to open air.

How far can a vent be from a sink?

Install the vent between the sink P-trap and the point where the waste line leading from the trap drops to the main sewer. If the waste line has a diameter of 1 1/4 inches, the vent can be no farther than 2 1/2 feet from the trap. If the waste line is 1 1/2 inches, this critical distance is 3 1/2 feet.

What is the proper way to vent plumbing?



Vent pipes must be installed so they stay dry. This means that they should emerge from the top of the drainpipe, either straight vertically or at no less than a 45-degree angle from horizontal, so that water cannot back up into them.

Can a plumbing vent run horizontal?

2. Can Vent Pipes be Horizontal? There is no problem with running your vent pipes horizontally as long as you remember that there should be a minimum clearance of 6 inches above the spill line.

How far can you run a drain without a vent?

If you have 1- 1/4-inch pipe, the horizontal distance of the vent ought to not be more than 30 inches. For a 1- 1/2-inc pipe the vent must be 42 inches away at the most while a 2-inch pipeline must have an optimum distance of 5 feet.

How far can a sink drain be from a vent stack?



There is a vent between the sink P-trap and the point where the waste line goes to the main sewer. The vent can’t be more than 2 1/2 feet from the trap if the waste line has a diameter of 1 1/2 inches. The critical distance is 3 1/2 feet if the waste line is 1 1/2 inches.

Can a toilet and sink share a vent?

A general rule is that you can only vent 2 fixtures on a toilet wet vent. The sink drain has a toilet vent through it. The toilet drain should be 3′′, the sink drain is 1.5′′, the shared sink drain/toilet vent area should be 2′′, and the vent going up should be 1.5′′.

Can two drains share a vent?

Common vent



This very simple concept allows two traps to be vented by the same vent. The two traps and their fixture drains can be either at the same level or at different levels, provided that they are on the same floor. The following diagrams show some of the various approaches to common venting.