I saw on wikipedia a mention of "combo tee" and "tee wye" is there a difference or are they the same?

I've also heard of something called a "sweep" or "long sweep" is that related here?


The combo tee has a longer sweep. Long sweeps are easier to run a snake through and drain better as the water path is gradually changed (if you have the space to use them).

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45 wye

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Combination wye & 1/8

  • Nice. Now I'm wondering what the difference between a "sanitary tee" and "tee wye" is they look really similar to me when I google them...(do they have different uses I wonder?) – rogerdpack Feb 1 '16 at 17:01
  • Usually sanitary are black pipe, the white is usually for rainwater and not as heavy plastic – Ed Beal Feb 1 '16 at 19:58
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    Sanitary tees are used ONLY for changing from horzontal to vertical. They cannot be used in the horzontal position. – ArchonOSX Feb 1 '16 at 20:58
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    @EdBeal Sanitary tees are available in both PVC and ABS, the color (material) does not help define the fitting. With a wye, the branch opening will not be perpendicular to the other openings. The branch opening of a sanitary tee is perpendicular, similar to a regular tee. However, with a sanitary tee the branch will have a sweep into the main body, rather than intersecting it perpendicularly. – Tester101 Feb 2 '16 at 0:09
  • OK based on what I'm seeing here I think there is no such thing as a "wye tee" its just another name for a "wye combo" if anybody disagrees let me know :) Thanks! – rogerdpack Feb 2 '16 at 18:18

This is a sanitary tee and can only be used as shown in the vertical orientation. They are only used to go from the horizontal to vertical plane.

If used flat (horizontal) they are prone to clogging. You must use a long sweep or wye+⅛ for horizontal DWV.

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  • When connecting a vent to a horizontal run of DWV, would this be the coupling to use? – 2 Left Thumbs Jul 12 '16 at 4:11
  • From my reading of the plumbing code, a sanitary tee can only be used in the vertical position as it is pictured above. If you are venting a horizontal run, in the middle of the horizontal part, you should use a sweep-tee or a wye-and-an-eighth combination. If you are venting a horizontal run where it switches from horizontal to vertical you can use a sanitary tee (vertically) instead of a 90° and then run the vent vertically from the top of the tee. – ArchonOSX Jul 12 '16 at 8:56
  • Here is a thread I started with my layout if it clarifies anything: diy.stackexchange.com/questions/94171/… – 2 Left Thumbs Jul 12 '16 at 13:21

A sanitary tee is legal for drainage in the horizontal to vertical position, however it is legal to use a sanitary tee in the hotizontal position when used for venting.

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