Fix a Leaky Tub Spout Diverter (But Don’t Make My Mistake!)
Fixing a Leaky Tub Spout Diverter — What I Learned the Hard Way
If your bathtub diverter is leaking and sending water down the spout instead of up to the showerhead, you’re not alone. A worn‑out gate, a stiff cup seal, or calcium buildup inside the spout can all cause the diverter to fail. But before you run out and buy a replacement tub spout, there’s one thing you absolutely need to check first—because I made this mistake myself.
In this post (and in the video above), I’ll walk you through the two different types of tub spout connections, how to identify which one you have, and how to repair a diverter using an inexpensive kit instead of replacing the entire spout.
Two Types of Tub Spout Connections (This Is Where Many DIYers Slip Up)
When I first looked under my tub spout, I expected to find a set screw. That’s the most common type—loosen the screw, slide the spout off, and you’re done.
But not all tub spouts use a set screw.
1. Slip‑On Spout (Set Screw Type)
- Uses a ½” copper pipe
- Tightened with a set screw underneath
- Easy to remove and replace
2. Screw‑On Spout (Threaded Type)
- Threads directly onto a nipple
- Sometimes the nipple is soldered onto copper
- No set screw underneath
In my case, I discovered there was no set screw. That meant I had a threaded spout, and the only way to remove it was to wrap the spout with a protective cloth and gently turn it with a wrench. Once it broke loose, it spun right off.
If you don’t check this first, you can easily damage the spout or the plumbing behind the wall.
Repairing the Diverter Instead of Replacing the Spout
Once I had the spout off, I decided to try a diverter repair kit. These kits are inexpensive and include:
- A new gate
- A new cup seal
- A replacement stem
Most plumbers won’t bother with this because it takes more time, but for a homeowner, it’s a great way to save money—especially if the spout itself is still in good shape.
Removing the Old Diverter Parts
The old gate and seal can be stubborn, especially if there’s calcium buildup. Mine didn’t look terrible, but the inside of the spout was heavily calcified, which was likely the real problem.