wet vent plumbing

What is Wet Vent Plumbing? (And Do You Need It?)

Wet vent plumbing is a system that allows waste pipes to also serve as a vent pipe. Wet vents are usually used for toilets and sinks. It has been around since the 1920s, but didn’t become part of the plumbing code until recently. Wet vents are very convenient and can save you money.

Wet Vent Plumbing
Wet Vent Plumbing

Why You Need A Wet Vent For Your Plumbing

Every plumbing fixture in your bathroom needs a vent. The venting system in your plumbing is very important. Venting allows fresh air to enter the pipes, which helps the process of drainage. They also allow gas from wastewater to escape and prevent other gasses from entering. Not having venting in your plumbing can cause many issues. Some of the most common issues are:

  • Bad odors in your home
  • Slow draining water
  • The emission of methane gas
  • Gurgling noises coming from your plumbing

How Does Wet Vent Plumbing Work?

Wet vents are typically installed for a toilet, sink, shower and/or bathtub. One system is used for the whole group of fixtures. This makes it possible to have one venting system for every plumbing fixture in your bathroom. It’s also possible to utilize this for other areas, such as your kitchen, but it’s most common in bathrooms. Wet vents drain water from one plumbing fixture and at the same time they vent air from another fixture within the same system.

Dry Vent vs Wet Vent

Wet vents allow waste to drain as well as vent the plumbing system. A dry vent only vents air and gas, and does not drain wastewater. A wet vent system takes care of two jobs, while the dry vent only does one. This means less materials and less money you have to spend to get the job done. As mentioned above, venting for all plumbing systems is highly recommended. Wet venting makes this convenient because you won’t have to worry about installing a venting system separate from your drainage

Rules and Codes

As stated before, there are certain codes you need to meet to install your wet vent plumbing system. To meet plumbing code requirements for your venting system, review some of the rules below. These rules will vary depending on what state you live in. The guidelines listed are the most common universal codes for the United States and Canada.

  • When connecting a toilet to your venting system, it requires it to be at the lowest point. No other fixtures or appliances can be at a lower level. 
  • Confirm that your pipes are the right size. The different sizes will determine how much the system can handle. Having a venting system that is too small can result in many issues such as leaking and clogging. When in doubt, choose a 3-inch or larger wet vent pipe and a 4-inch waste line pipe. 
  • Depending on the area you live, there are different size requirements for how long your pipes can be. If the pipes are too short, it could cause a hydraulic overload. Hydraulic overload occurs when the system is not equip to handle the amount of wastewater from through. This prevents the system from working properly.
  • The plumbing fixtures you want to connect have to be located on the same floor. Your wet vent plumbing system can’t connect a toilet on the first floor with a sink on the second floor. 
  • For every 4 feet of horizontal pipe you have, you need a pipe supporter. This secures your pipes so you won’t have any issues of them not being stable enough. 
  • The angle of how your drain connects to the vent has to be more than 45 degrees.
Wet Vent Set Up Diagram
Wet Vent Set Up Diagram

Final Thoughts

A wet venting system is very convenient for your home’s plumbing. Because we recommend to have venting for all of your plumbing, the wet vent allows you to take care of venting and draining all in one system. If you are looking to install one in your home, make sure to review the plumbing code beforehand. It’s also beneficial to have your wet vent inspected by a professional to make sure it’s up to code. If you need help installing or repairing your wet vent system, call your local plumber to help you out!

Call 1-Tom-Plumber

Don’t hesitate to contact us here or call us at 1-Tom-Plumber (1-866-758-6237) if you need a plumbing service. 1-Tom-Plumber’s certified team of plumbers and drain technicians respond immediately to any emergency plumbing, drain cleaning, or water damage problem. We also handle the excavation of underground water lines and sewer main lines. Our immediate-response team is available every day and night of the year, even on holidays.

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