What plumbing fixtures need vents? (2023)

What fixtures should be vented?

As part of the new regulations in compliance with building codes, you are required to have a plumbing vent and a trap for every fixture in the home that requires plumbing, for example, toilets, bathtubs or sinks.

All residential plumbing fixtures need to be protected by a plumbing vent. Vents are frequently connected together inside the attic, which allows for fewer penetrations in the roof.

Plumbing vent pipes supply fresh air to each plumbing fixture in the house, which helps the system move water through the drainage pipes each time a toilet is flushed or a sink is drained.

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.

Venting is necessary for bathroom plumbing systems to prevent blockage. All pipes in your home, particularly for toilets, sinks, and showers, require proper venting. It protects the trap on the drain pipe. In addition, it helps you secure your wallet, fittings, time, and even the pipe itself.

And the answer is yes, your toilet has to have a vent. For more information on the great importance of plumbing vents, read our plumbing vent article here. And the size of this vent pipe depends on your local plumbing code. If your code is the IPC, then your toilet's individual vent is sized at 1.5.”

Poorly-vented drain lines will not be able to effectively move wastewater and solid waste out of your building. This could lead to problems such as overflowing drains, backed-up toilets, and similar plumbing issues.

If your bathroom isn't properly ventilating (or worse…not ventilated at all!), all of the excess moisture will be absorbed by your walls, ceiling, and floors. Having excessive moisture trapped in your home's structure will result in mold growth and moisture damage that's expensive to remove and repair.

A vent is a necessary part of the drain system for any plumbing fixture. Its purpose is to equalize pressure in the pipes and prevent a vacuum from forming as the fixture drains.

Can a shower and toilet share a vent?

Wet vents are typically used when plumbing a bathroom group. So yes the shower can also be vented by the wet vent along with the toilet. There is one major stipulation when wet venting multiple fixtures when a toilet is one of them: the toilet must be the last fixture connected to the wet vent.

It can attach directly behind the fixture or to the horizontal drain line. If two fixtures are on opposite sides of a wall, they can tie into the stack with a sanitary cross. This is called a common vent and can be found on back-to-back sinks.

A horizontal wet vent could have as few as two fixtures or as many as ten fixtures but not more than two fixtures of any type can be connected to the system. Each wet vented fixture drain shall connect independently to the horizontal wet vent.

For pipes that have a diameter of 3 inches the distance is 6 feet and for a 4-inch pipe the most it should be away from the vent is 10 feet. Keep in mind that toilets have their own traps so there is no need to have one on the drain line, but it still must have a vent.

A connection between a vent pipe and a vent stack or stack vent shall be made not less than 6 inches (152 mm) above the flood level rim of the highest fixture served by the vent. Horizontal vent pipes forming branch vents shall be not less than 6 inches (152 mm) above the flood level rim of the highest fixture served.

Any new kitchen, bathroom (or shower room), utility room or toilet should be provided with a means of extract ventilation to reduce condensation and remove smells.

So now the question comes up, if installing waterless urinals, which use no water whatsoever, do they need to be vented? The answer is yes. The waterless urinal must also be connected to the plumbing tree. Here's why.

One or two vented lavatory(s) shall be permitted to serve as a wet vent for a bathroom group. Only one wet-vented fixture drain or trap arm shall discharge upstream of the dry-vented fixture drain connection.

Bathtubs need a vent to allow proper drainage and water displacement. Check with your state's code if you install a bathtub with no vent, as it varies from state to state. Depending on your state, your code may change on the plumbing and what needs to be done to stay within your venting code.

Use of a ceiling vent

Installing a ceiling vent is probably the most efficient way to ventilate a bathroom with no outside access. A ceiling vent is a unique machine that allows air to escape from the bathroom. In other words, it's a machine that, like an open window, allows moisture to escape from your bathroom.

Can you vent a toilet with a 2 inch pipe?

Toilet Vent Pipe Size? It's typically recommended that you go with a 2" PVC pipe for the vent. This is according to the uniform plumbing code (UPC). It may not be enough, depending on how many fixtures you are trying to run off the vent.

All plumbing fixtures—including washing machines—must be vented. Improperly vented drains can be sluggish and noisy, and can emit hazardous fumes. Properly vented drains allow the P-trap to do its job: prevent sewer gases from escaping into your home.

The most common configuration is to feed 2" PVC down from the ceiling within the wall behind the toilet. The vent pipe connects into the toilet drain pipe. The sink drain pipe and the tub/shower drain pipe are vented with 1.5" pipe that branches off from the 2" PVC mainline.

When you flush with the lid up, your toilet shoots out tiny water particles mixed with your waste. Known as toilet plume, these particles could contain harmful bacteria. Toilet plume has been shown to land on nearby surfaces, and the bacteria can live for months.

Yes, every toilet needs a vent pipe to work well. Without it, your toilet could not get rid of waste and debris. The toilet needs venting to balance the atmospheric pressure, enable the flush system, and prevent awkward smells.