Diverter Valve

A diverter valve is a valve that redirects water flow from one outlet to another without shutting the water off. The most familiar example is the tub spout diverter — the pull knob or lever on a bathtub spout that redirects water from flowing out the spout to flowing up to the showerhead. In multi-outlet shower systems, diverter valves route water between a fixed showerhead, hand shower, body sprays, or other outlets.

What types of diverter valves are there?

• Tub spout diverter (built-in): the simplest type — a pull-up gate inside the tub spout that blocks the spout outlet and directs flow to the showerhead riser pipe. The gate has a slight intentional leak (letting ~10% flow from the spout) to prevent the diverter from freezing stuck. When the shower is turned off and water pressure drops, the gate falls back to the open position.
• Three-way diverter valve: installed between the shower valve and two outlets (showerhead and hand shower, or two showerheads). Has three positions: outlet 1 only, outlet 2 only, or both simultaneously.
• Transfer valve: a volume-neutral diverter used in thermostatic shower systems that redirects flow between multiple body jets, rain heads, and hand showers independently.

What are common diverter valve problems?

• Tub spout diverter won't divert: the gate has corroded in place or the O-ring is worn — replace the tub spout ($15–$50)
• Diverter leaks back to tub during shower: the gate seal is worn — if more than ~10% flows from the spout, replace the spout or diverter cartridge
• Multi-function diverter valve leaks at handle: cartridge O-ring failure — a plumber can rebuild or replace the cartridge for $150–$350

Tub spout diverters are among the simplest DIY plumbing repairs — pull off the old spout (either it's a slip-on held by a set screw, or it's a threaded type), thread or push on the replacement, done.