Combination Tees vs. Sanitary Tees: What’s the Difference and When to Use Each?

When it comes to wastewater systems, the right plumbing fittings are the key to a setup that runs efficiently and complies with plumbing codes. Among the many types of plumbing tees available, combination tees and sanitary tees are two useful options. While they may appear similar at first glance, each serves a different purpose in plumbing systems. Let’s take a look at each to help you select the right fitting for your job.

What Are Sanitary Tees?

A sanitary tee is designed to connect a horizontal drain line to a vertical drain or vent pipe. As you may be able to tell from the name, this plumbing tee has a T-shaped design with a smooth curve that directs wastewater downward. Sanitary tees are crucial in maintaining proper flow and preventing backups, so wastewater moves efficiently while allowing air to enter the plumbing system for proper drainage and venting.

For another look, check out this blog: What is a Sanitary Tee: Everything You Need to Know.

Best Use Cases for Sanitary Tees:

• Connecting horizontal waste lines to vertical drain stacks

• Used in venting systems to maintain proper air balance

• Installed in residential and commercial drainage systems

• Preferred for applications where wastewater must flow downward without obstruction

Sanitary tees are an excellent choice for waste applications but are not ideal for horizontal-to-horizontal connections, as they do not provide the smooth transition necessary to maintain optimal flow.

What Are Combination Tees?

A combination tee is a hybrid plumbing tee that combines features of a sanitary tee and a wye fitting. This plumbing tee has a sweeping 45-degree angle that allows wastewater to transition more smoothly between horizontal and vertical pipes. The curved design reduces turbulence and improves the overall flow of wastewater, making it particularly useful in certain drainage configurations.

Best Use Cases for Combination Tees:

• Connecting horizontal waste lines to other horizontal or vertical drains

• Used when a smoother transition is needed to prevent clogging

• Ideal for high-efficiency drainage systems with better flow dynamics

• Suitable for long horizontal runs where minimal resistance is crucial

Because of its sloped design, a combination tee is often a better choice than a sanitary tee when dealing with horizontal drain line connections.

For an overview of combination tees, watch this video on YouTube!

Choosing the Right Plumbing Tee for Your Project

When selecting between a sanitary tee and a combination tee, consider the direction of wastewater flow and the overall efficiency of the drainage system:

Use a sanitary tee if you are connecting a horizontal waste pipe to a vertical drain or if you are incorporating venting into your plumbing system.

Use a combination tee if you need a smoother transition between horizontal pipes or want to improve the efficiency of long horizontal waste lines.

Both fittings are essential in plumbing systems, but selecting the right one will help prevent issues like slow drainage, clogging, and improper venting.

Get the Right Plumbing Tees for the Job at SquarePeg

At SquarePeg, we provide high-quality plumbing supplies from top manufacturers to help you complete your project with confidence. Whether you’re working on residential or commercial plumbing, our selection of durable and code-compliant sanitary tees and combination tees will allow your plumbing system to function efficiently. 

Browse our selection today and find the right plumbing components for your needs!