How to Vent a Kitchen Sink That is Under a Window: The Definitive Guide

By Kristy Warren •  Updated: 01/31/21 •  6 min read

Who doesn’t love a kitchen sink with a window? Looking outside the window and doing the dishes is the minimum luxury everyone deserves.

Although, many people don’t know how to vent a kitchen sink under a window. Because the plumbing and wiring process can get a little hard. Let me explain:

You see, without vents, negative pressure can empty P-traps in the pipes. This allows sewer gases to enter your home. Normally, winds rise from each fixture to join a central vent stack that extends through the roof. So, it is quite important that you do everything correctly.

But the best part is if you follow this article, venting a kitchen sink will be a piece of cake for you.


How to Install a Vent Pipe for the Kitchen?​

Adequate sink ventilation is very necessary for your kitchen. The sink may experience slow drainage and water locks in the drain pipes without proper ventilation.

Proper sink ventilation reduces clogs and makes sure disposal waste drain efficiently to the main sewer line. So, when installing a vent pipe every step is important.

However, this step-by-step process is guaranteed to teach you how to vent a kitchen sink under a window. Now, let’s take a look at the steps.

Step 1: Connect the Sink and Waste Drain Pipe

To connect the horizontal sink drain pipe to the2-inch waste drain pipe from the toilet, add a 2-by-2-by-1.5-inch PVC sanitary T-Fitting. This connection is located directly behind the sink, in the stud space in the wall.

This fitting has three openings. The 2-inch side opening attaches to the sink pipe and faces downwards with the other2-inch opening.

The gap of 1.5 “faces up. Use the PVC primer and PVC adhesive as indicated in their respective containers when installing PVC pipes and fittings.

Step 2: Select the Vent Pipe Configuration

Decide the vent pipe configuration. The vent pipe must extend upward a short distance from the top of the sanitary T-fitting. Then turn and extend horizontally through the wall studs until it enters a stud space where it can once again ascend vertically.

Step 3: Attach Pipe to the Opening

Cut the pipe saw into a small vertical piece of 1 1/2-inch PVC pipe. And attach it to the opening at the top of the sanitary T-fitting using the PVC primer and adhesive.

The length of this component depends on the horizontal pipe’s width and slope but usually, it should be around 2 inches long.

Step 4: Draw a Chalk Line

Snap a chalk line to the wall studs’ sides to reflect the length and slope of the horizontal vent drain. The horizontal pipe will slope upwards at 1/4-inch level per foot.

For example, if it is 4 feet from the connection of the elbow to the stud space where the vent pipe will turn upwards. Then the second turn must be 1 inch higher than the connection of the elbow.

Step 5: Drill a 1 3/4-inch hole

Mount a 1 3/4-inch hole bit drill. Then use the chalk line to drill a hole through the middle of each wall stud to run the horizontal vent pipe as a rough guide.

Step 6: Add a second Elbow Fitting

Push the horizontal pipe through the holes and attach it to the elbow fitting. Add a second elbow fitting at the end of the pipe, with the gap facing upwards.

Step 7: Install a Straight-up Vertical PVC Vent Pipe

Install a straight-up vertical PVC vent pipe until you get to the attic. To get the pipe in, you’ll need to drill through the ceiling plates.

Step 8:  Attach Another PVC Elbow

Add another PVC elbow to the top of the vent pipe in the attic. You have to run the pipe horizontally, with the proper slope, to reach the central vent-and-soil stack of the building. It is either 3 or 4 inches in diameter, depending on local codes.

Step 9: Connect Vent Pipe to the Stack

Attach the vent pipe to the stack, using a PVC T-fitting to match the stack’s diameter and the 1 1/2-inch sink vent pipe.


Why Is the Kitchen Sink Usually Placed Under a Window?

If you were to look in most of the homes ‘ kitchens, you’d find a sink under the outside window. Although there is no general rule that the kitchen sink must be placed under a window, here are a few reasons why people have the sink there.

1. Efficient use of cabinet space: If you want a window somewhere in the kitchen, the sink is always the best option. The sink area is logical as cabinets interfere with the functions of using a sink in the kitchen.

2. The View: You have the opportunity to connect with the exterior space while you are standing washing or rinsing dishes. The view might be ocean fun, or just keeping an eye on the kids.

3. Interior Aesthetics: A kitchen has a few visual focal points, one of which is the kitchen sink since it is one of the most important work areas in this room. Windows dress up this area of work to make it physically more appealing.

4Natural Light: Natural light in a kitchen is a high priority. Morning breakfast is always imagined sitting at a table or on an island where the rays of the morning sunshine in. No matter what time of day the sun is always welcome.

5. Breeze / Wind: Outdoor connection and “mother nature” is a priority. To let the fresh flowers smell out of the garden, perhaps letting smells out of the area, is an important feature of a kitchen.



A kitchen is not complete without a proper kitchen sink. And the venting is a vital part of that. It keeps your pipes from clogging. Furthermore, it protects your health from dangerous gases. After reading this article I guess you know all of these things in detail.

I hope this tutorial helped you and don’t forget to share your experience in the comments section below. Good luck!

Check other resources related to kitchen :

1. How To Keep Water & Coffee Hot For A Long Time?

2. How To Deep-Clean A Greasy Tea Kettle Ways The Simplest


Kristy Warren

Hello, I’m Kristy and the person behind I regularly post daily life kitchen-oriented things like kitchen hacks, kitchen tools, utensils, and related articles. The purpose of this blog is to make an archive and share my ideas and knowledge with my followers.