Step 6 · Reassemble and Test for Leaks

This is the step people usually slow down on. Go finger-tight first, then a quarter turn. No rush — replay the clip whenever it helps.

Before reinstalling the trim, it's time to test for leaks. Go back to your main water shut-off valve and turn it on VERY SLOWLY. This allows the pipes to fill gradually. Go back to the shower and closely inspect the area around the newly installed cartridge stem for any drips or spraying water. If you see any leaks, shut the water off immediately and re-check your installation (e.g., is the bonnet nut tight enough? Is the clip fully inserted?). If everything is dry, you can proceed with reassembly. Slide the trim plate back over the valve and secure it with its screws. Re-install the handle, tightening the set screw with your Allen wrench. Turn the shower on and test its full range of motion, ensuring both hot and cold water are working correctly and are not reversed. Perform one final check for any leaks around the handle or behind the trim plate.