Tank to Pump

Pump Operations

Cavitation

Cavitation is what happens when the pump tries to discharge more water than the intake can supply, forming vapor pockets that collapse violently inside the pump. The discharge pressure becomes erratic and the pump can damage itself.

A pump schematic with a compound intake gauge. In the normal scenario the gauge reads a positive feed and the discharge line runs full; with the hydrant overdrawn the needle sags into vacuum and a hunt band appears; with the tank run-dry the boost tapers to nothing. The active scenario is chosen with radio buttons and announced in a live status region.

Cavitation · interactive

STEADYThe intake is fed and positive: the pump has all the water it needs, the gauges sit still, and the lines run full.

Scenario

Supply meets demand. The intake stays positive, the gauges are steady, and the pump moves water without entraining air.

Cavitation is not a knob you turn — it emerges when the pump demands more water than the intake can supply. These are training estimates; the gauge reading and wobble are illustrative. Follow your SOPs and your apparatus's own gauges and limits.

Cavitation is not a control — it emerges when the pump demands more water than the intake can supply. Step through three scenarios to see how it shows up: a steady gauge on a healthy feed, a hunting intake that sags into vacuum when the hydrant is overdrawn, and a tapering boost as the tank runs dry.

When demand outruns supply, the pressure on the intake side drops low enough for water to flash to vapor. Those bubbles collapse as they hit higher pressure in the pump, pitting the impeller and making the discharge surge and chatter — operators call it running away from the water.

The cure is to stop asking for more than the source can give: back off the throttle or reduce flow until the intake can keep up. Cavitation is the pump's warning that the operator has overdrawn the supply.

Common questions

What is cavitation?
Cavitation is what happens when the pump tries to discharge more water than the intake can supply. Pressure on the intake side drops enough for water to flash to vapor, and those bubbles collapse violently inside the pump — the discharge pressure goes erratic and the pump can damage itself.
How do you stop cavitation?
Stop asking for more than the source can give. Back off the throttle or reduce the flow until the intake can keep up. Cavitation is the pump's warning that you have overdrawn the supply, so the fix is always to relieve the demand.
What does 'running away from the water' mean?
It is the operator's phrase for cavitation — driving the pump faster than the supply can feed it, so the pump effectively outruns its own water. The discharge surges and chatters because vapor pockets are forming and collapsing instead of solid water moving through.

Where this shows up

See also