Leaky Tub Diverters, Tub Spouts and Shower Arms:
Small Bathroom Leaks Russ Finds Often

The diverter that doesn’t divert

On most tub-shower combos, a pull-up knob on the tub spout (or a third handle on the wall) sends water up to the shower head. When the gate or washer inside wears out, part of the water keeps pouring out the spout. A Portland report described it: the diverter allowed water out of the tub spout when engaged, which points to a worn washer or a failing gate mechanism.

It wastes water and weakens the shower. Because the diverter is usually built into the spout, the fix is often a new spout. A licensed plumber can match the connection type, since some spouts slip on and others thread on.

The gap behind the tub spout

Tub spout sealant came up in 22 houses. When shower water runs down the wall, it hits the top of the spout. If there’s an open gap between the spout and the tile, some of that water goes into the wall. Russ’s report wording: failed or missing sealant around tub spouts should be replaced to help prevent moisture intrusion.

Many plumbers seal the top and sides and leave the bottom open a bit so water can get back out. Look at it after a shower. A spout that wiggles or sits away from the wall is a separate problem, often a short pipe stub or a loose fitting behind it.

Leaks at the shower arm and head

Thirteen houses had a leak where the shower head threads onto the arm, and another 13 had a dripping head. Most of these drip only while the shower runs. A little thread tape or a new washer usually stops it.

A loose arm is the one to take seriously. In a Vancouver house, the second-floor hall bath had a shower arm that moved noticeably in the wall. Russ’s report gave the reason: a loose arm can work the threaded joint behind the wall loose, and that joint can leak inside the wall where no one sees it, damaging the tile and grout around it. The shower tile post covers what water behind tile does over time.

What to look at below

A second-floor bathroom with a leaky fitting often shows it on the ceiling below. Russ looks for stains under bathrooms and uses thermal imaging, which can show cool patterns consistent with moisture but doesn’t confirm a leak on its own. The ceiling stains post covers how he reads them. In the crawlspace, he looks at the floor framing under the tub.

What Russ checks

He runs the tub and shower, engages the diverter, and looks at the spout, head and arm, the tile and grout around them, and the caulk at the tub. He looks for stains on the ceiling below and in the framing under the bathroom where accessible. He doesn’t remove fixtures or open walls. Leaks and loose fittings get a recommendation for a licensed plumber.

For the rest of the bathroom, the guide to what to look at in bathrooms before you make an offer covers fans, toilets and tile. To set up an inspection, you can book online.