1-1/2" PVC DWV Sanitary Tee: A Complete Guide
By Maintenance Depot Plumbing Team · Last reviewed
Quick answer
A 1-1/2" PVC DWV sanitary tee connects a horizontal fixture drain, like a bathroom sink, to a vertical drain or vent pipe. Install it on a vertical pipe with the curved inlet pointing down toward the flow.
The 1-1/2" PVC DWV sanitary tee ("san tee") is one of the most common fittings in drain, waste and vent (DWV) plumbing. It connects a horizontal fixture drain, such as a bathroom sink, to a vertical drain or vent pipe.
Specs at a glance
| Spec | Detail |
|---|---|
| Product | Sanitary tee (san tee) |
| Size | 1-1/2" |
| Material | PVC |
| System | DWV (drain, waste, vent) |
| Orientation | On vertical pipe, sweep pointing down |
What makes a sanitary tee different
Unlike a plain tee, a sanitary tee has a curved inlet on the branch. The sweep guides waste downward in the direction of flow, which reduces splashing and blockages and lets air move freely through the vent.
Orientation matters
- The branch connects to the horizontal fixture drain.
- The curve must point down, toward the direction of flow.
- Install the tee on a vertical pipe. Don't lay a sanitary tee on its back in a horizontal drain line; use a wye or combination fitting there.
Typical uses
- Bathroom sink and vanity drains
- Kitchen sink drains in 1-1/2" systems
- Vent tie-ins above fixtures
Installation steps
- Measure and cut the stack, allowing for the socket depth of the tee.
- Dry-fit everything and mark alignment lines.
- Clean and prime the pipe ends and fitting sockets.
- Apply DWV-rated PVC cement, push the pieces together with a quarter twist and line up your marks.
- Hold each joint for about 30 seconds and let it cure before running water.
Slope your horizontal drain
Horizontal drain lines should slope toward the stack at about 1/4" per foot. Too little slope lets solids settle; too much lets water outrun the waste.
Need a larger size? Maintenance Depot also stocks the 3" PVC sanitary tee for main drain lines.
Frequently asked questions
Can a sanitary tee be installed on its back?
No. A sanitary tee should not be laid flat in a horizontal drain. Use a wye or combination wye and 1/8 bend instead.
What slope do horizontal drains need?
About 1/4" per foot toward the stack is the common rule for small-diameter drains.
Is DWV pipe the same as pressure pipe?
No. DWV fittings are designed for gravity drainage and should not be used on pressurised water supply lines.
Buy 1-1/2" PVC DWV Sanitary Tee (San Tee) at Maintenance Depot