How to Fix a Shower Diverter (Tub Spout Leak)

A shower diverter is the little valve that redirects water from the tub spout up to the shower head. When it wears out, you get the classic symptoms: water keeps pouring from the tub spout while the shower dribbles, or you cannot get full pressure up top. As a licensed plumber, here is how to identify your diverter type and fix it – most are a cheap, quick repair.

How a shower diverter works

When you pull the knob on the tub spout (or turn a separate handle), you close off the path to the spout and force water up to the shower head. Over time mineral buildup and worn seals stop it sealing fully, so water leaks back down to the spout and your shower loses pressure.

Identify your diverter type

• Tub-spout (pull-up) diverter: a small knob on top of the tub spout you lift. Most common, and the easiest fix – usually you just replace the whole spout.
• Single-valve diverter: built into the main shower handle/cartridge.
• Three-valve diverter: a separate center handle between hot and cold (common in older two-handle showers).

Fix 1: The pull-up tub spout (most common)

If your diverter is the knob on the spout, the mechanism is inside the spout and is not serviceable – you replace the spout. Unscrew the old one (either a set screw underneath or twist it off counter-clockwise), note whether it is a threaded or slip-on type, and install a matching new spout with plumber’s tape on the threads. Ten-minute job, often under $20.

Fix 2: Three-valve diverter

Here the fix is usually a new diverter stem or washer. Shut off the water, remove the center handle and unscrew the diverter stem, and replace the worn washer or the whole stem assembly. This is the same skill as fixing a leaky two-handle faucet – see how to fix a dripping faucet, which covers stem and washer replacement.

Fix 3: Single-valve cartridge diverter

If the diverter is built into a single-handle shower valve, a worn cartridge is usually the culprit. Replacing it restores both diversion and pressure – browse replacement cartridges and match the brand and model.

Still weak after the fix?

If diversion works but the shower itself is weak, the head or arm may be the limiter – see high-pressure shower heads and shower arm options. If you are not comfortable behind the valve or the wall plumbing is corroded, this is a fair one to hand off – gut-check it with when to DIY vs call a plumber.

Frequently asked questions

Why does water still come out of the tub spout when the shower is on?

That is a failing diverter. The diverter is supposed to seal off the spout and send water up to the shower head, but worn seals or mineral buildup let water leak back down. On a pull-up tub spout the fix is simply replacing the spout; on a three-valve setup it is a new diverter washer or stem.

Can I fix a shower diverter myself?

Usually, yes. The most common type – a pull-up knob on the tub spout – is fixed by swapping the whole spout in about ten minutes for under $20. Three-valve and cartridge diverters take a bit more work but are still standard homeowner repairs. Call a pro only if the valve body is corroded or you are not comfortable behind the wall.

How much does it cost to fix a shower diverter?

If you DIY a tub-spout diverter, often under $20 for a new spout. A replacement cartridge or diverter stem runs roughly $15 to $50. If you hire a plumber, expect $100 to $250 in labor depending on the type and access. The pull-up spout type is by far the cheapest and easiest.