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How to Vent a Kitchen Sink Under Window

Looking out of the window while washing your dishes is the best. You cannot pass on the opportunity to put your kitchen sink right below a window. However, you should learn how to vent a kitchen sink under the window after you are done installing it.

How to Install a Vent Pipe for the Kitchen Sink Under Window? Step by Step Guide

Kitchen sink ventilation is essential to avoid any blockages and slow drainage. A proper ventilation system ensures the water drains properly and the water system remains efficient. Follow the simple guide below to learn how to install a vent pipe for the kitchen sink under the window.

Step by Step Guide on How to Install a Vent Pipe for the Kitchen Sink

1. Connecting the sink to the waste drain pipe

You will need a 2-by-2-by-1.5-inch PVC T-Connector and connect it to the horizontal drain pipe under your sink. This is in the stud space behind the sink, on the wall. You will find three holes in this setting. The two-inch opening which is on the side attaches to the sink pipe. The other one faces down. And the 1.5-inch opening faces upward. Next, you should check the instructions on the PVC primers and PVC adhesive canisters to install the PVC pipes.

2. Configuring the vent pipes

First, you should determine where you want the vent pipes. Next, you should keep a small length within the top of the t-fitting and the vent pipe. After that, it extends sideways through the wall studs until the pipe reaches a vertical stud space from which it can rise.

3. Connecting the pipe and the hole

Trim a lateral piece of PVC pipe 1 1/2 inches long with a pipe saw, then use PVC primer and PVC glue to fix it to the top of the sanitary T-fitting. The length of the whole component varies depending upon the size and slope of the horizontal pipe. It should be about two inches long.

Kitchen sink vent pipes

4. Drawing a line that can extend beyond the window

To replicate this data, measure the size and slope of the horizontal vent drain and draw a line all around wall framing. According to the line marked on the wall studs, the lateral vent pipe will incline upwards to 1/4 inch per foot.

5. Drilling a 1 3/4th inch hole

Drill a 1 5/8-inch hole within every stud between the vent rise and the elbow. Make sure that each hole is aligned with the line. It would help if you used a saw to finish the job. By putting the horizontal pipe through the openings and attaching it to the elbow fitting, you can connect it. Next, install the other elbow fitting with the hole facing upwards at the end of the horizontal pipe.

6. Installing a straight-up PVC vent pipe

You should drill through the ceiling plates to connect the straight-up PVC vent pipe to the attic. Next, connect another PVC elbow to the vent pipe in the attic. The vent pipe should be run horizontally through the attic with the proper slope until it touches the main vents and soil stacks.

PVC vent pipe

7. Joining the vent pipe and the stack

Depending on local standards, the vent pipe size must be 3 or 4 inches. Next, connect the vent pipe to the stack with a PVC T-fitting whose dimensions match the stack’s size and the 1 1/2-inch sink vent pipe.

However, you must keep the following considerations in mind when putting these procedures into action. First, ensure your new vent has a slope of at least 1/4 inch per foot before running it through the attic. Examine the materials that you used to construct the existing vents.

If your main vent or other vents are made of PVC pipes, you should use the same ones for venting your kitchen sink, and instead of using other glues, link the pipes with PVC glue.

Also Read: How To Remove Scratches From Stainless Steel Sink

Why Place Your Kitchen Sink Under a Window

Here is why you would want to place your kitchen sink under a window:

Why Place Your Kitchen Sink Under a Window
  1. Who doesn’t love to watch out of the window while you’re cleaning dishes? It’s the best reason to place your kitchen sink under a window!
  1. It’s a great way to save power as you will be washing dishes in front of your window and hence will not feel the need to switch on any lights in the kitchen.
  1. You will reduce your installation costs by having as many appliances on one wall. You can put your hot and cold water pipes on the outer wall. 
  1. It is an efficient use of space like other kitchen appliances like a refrigerator, or you cannot place a machine under a kitchen window. 
  1. If you are too lazy to wash your dishes right away, placing your kitchen sink under the window helps you by making them not smell. Ventilation is a big upside to generally prevent a foul-smelling kitchen, and placing your kitchen sink under a window can help you with that. 

Advantages of Venting a Kitchen Sink Under Window

Vents are required for all kitchen sinks. This does not, however, apply to the fan above your stove. Alternatively, a sink vent is built into the plumbing to keep sewer gas out of the house. In addition, it prevents a vacuum from forming by equalizing tension inside the pipes by letting air mix with the water.

Advantages of Venting a Kitchen Sink Under Window

Your sink will not drain efficiently if it is not ventilated. It can not only allow sewer gases into your home, but it can also hinder human waste, unclean water, and other trash from being cleaned from the pipes. Drains are angled down to let gravity help in waste collection.

Symptoms Of Inadequate Or Non-Existing Ventilation:

Although a lack of ventilation may appear insignificant, sewer gas exposure can lead to sickness and death. Call a plumber to inspect your drainage system if you see any of the following:

1. Bubbles in the toilet bowl

Even a few bubbles can indicate a larger issue. For example, if your sink lacks a vent, it will attempt to draw air from other sources. You’ll notice bubbles in places like the toilet while it accomplishes this.

2. Drainage is slow

Slow drainage happens when there is no vent to a sink. If you’re convinced there’s no blockage and you’ve tried everything to enhance drainage, the issue is most likely due to a lack of a vent in your sink.

Slow sink drainage

3. Gurgling sounds 

Drains aren’t supposed to gurgle or burble. These noises are caused by a lack of airflow in your toilets, bathtubs, or sinks. Waste and water have a tough time moving through the pipes due to this.

4. Clear toilet bowl 

If your toilet bowl is empty or only has a small amount of water left after flushing, it could indicate poor ventilation. This is due to a loss of pressure, which causes the water to flow away.

5. Drains smelling bad

Sewer gases will not be confined within the pipes if there isn’t a vent. As a result, sewage odors may emanate from your sink drains.


How far can a kitchen sink be from a vent?

At least one vent for plumbing fittings is required in every building. As a result, some sinks may share the same vent. A vent pipe’s smallest diameter is one and 1/4 inches. Therefore, if your vent is a one-and-a-quarter inch in diameter, it should be no more than two and a half feet away from the sink trap.

How high should a window be above a kitchen sink?

Have a large window over the kitchen sink if at all possible. Windows that start just above the counter give the impression that your space and the outside are connected.

What size window should be over a kitchen sink?

We recommend counter height and bumped-out windows and to watch how far the bump-out goes. If it’s really deep, it can get harder to open the windows and clean the back of the counter. You can keep it to 10 or 12 inches, if possible.

Wrapping Up

A kitchen sink under a window is an aesthetic and an intelligent choice. You can look at the advantages of having one under a window, why it is vital to have a vent for a kitchen sink, and how to install one by reading our article.