Short definition
A diverter is the small internal valve in a kitchen faucet (or tub spout) that switches water from one outlet to another — spout to side sprayer, spout to pull-out hose, or tub spout to showerhead. When a sprayer goes weak or water pours from the tub spout while the shower is running, the diverter is the first suspect.
What it is
In a kitchen faucet, the diverter is a spring-loaded plunger buried under the spout cap. When you press the sprayer trigger, backpressure on the spout drops; the spring lifts the plunger, redirecting water through the sprayer hose. Release the trigger and the plunger falls back, sending water out the spout again.
In a tub spout with an integrated diverter, you pull up on a small knob on top of the spout. That lifts an internal gate, blocking the spout outlet and forcing water up the riser to the showerhead. Three-handle tub/shower setups use the center handle as a separate diverter valve.
Why it matters to a homeowner
If your kitchen pull-down or side sprayer has gone weak even though the rest of the house has full pressure, clean the sprayer head first, then suspect the diverter. Most diverter cartridges are fingertip parts under the spout cap — pop the cap, lift the diverter, soak it in vinegar, replace if needed ($5 to $25). Pro labor is $80 to $150, which is honestly more than the part deserves.
If your shower runs but water still pours out the tub spout in roughly equal proportion, the tub-spout diverter has failed. Replace the whole tub spout — the diverter isn’t a separate part on most spouts.
Common failure modes
- Mineral scale fouls the diverter spring. Sprayer goes weak or stops working. Vinegar soak or replacement.
- Diverter check valve fails reverse-direction. Water comes out the spout AND the sprayer at the same time.
- Tub-spout diverter spring breaks. When the shower is engaged, water still flows from the tub spout (often a 50/50 split). Replace the spout.
Common variants and what it isn’t
- Faucet diverter (kitchen) vs. tub-spout diverter (bath). Different mechanism; same name.
- Internal diverter vs. external diverter. Most modern faucets are internal. Some older designs use a ring valve at the spout exit.
- Three-handle shower diverter. The center handle in a three-handle tub/shower set is an entirely separate diverter valve, not a small internal cartridge.