# The pump runs but delivers no water: causes and what to check yourself

> Why a surface pump or booster set runs but delivers no water: air in the suction pipe, air leaks, the foot valve, suction depth and the water level in the source.

Web page: https://watertrade.com.ua/en/articles/article/nasos-ne-kachaet-vodu · Other languages: [UA](https://watertrade.com.ua/articles/article/nasos-ne-kachaet-vodu.md), [RU](https://watertrade.com.ua/ru/articles/article/nasos-ne-kachaet-vodu.md)

*November 11, 2026*

![Diagram: well with a low water level, suction pipe with air bubbles and a leaking joint, a pump with its priming plug and a pressure gauge](https://watertrade.com.ua/uploads/articles/pump-no-water.jpg)

The pump switches on and the motor hums, but no water comes, or it comes in spurts. Usually the pump itself is fine: a surface pump cannot draw air, and any gap in the suction line starves it of water. Check things in order, from the source to the pump.

## What the diagram shows

1 — a foot valve with a strainer on the end of the suction pipe, 2 — a loose joint where the pump draws in air, 3 — the pump’s priming plug, 4 — a pressure gauge.

## What to check

1. **Is there water in the source?** In summer and after long use the water level in a well drops. If the end of the pipe is above the water, the pump is drawing air. Lower the pipe, or wait for the well to refill.
2. **Is the pump primed?** Before the first start, and whenever the system has drained, fill the pump body and suction pipe with water through the priming plug until it overflows. A surface pump cannot lift water without this.
3. **Does the foot valve hold?** If water runs back into the well after the pump stops, the pump has to start from scratch every time. Pull up the pipe and check the valve and strainer: silt often clogs them, or a grain of sand jams the valve. See [“Check valves”](https://watertrade.com.ua/en/articles/article/obratnyj-klapan).
4. **Is there an air leak?** Bubbles in a clear section of pipe, spluttering water and pressure that never builds are signs of air getting in through a thread or a crack. Tighten the joints and check the pipe along its whole length.
5. **Is the water too deep?** A surface pump usually lifts water from no deeper than 7–8 m, and that includes the resistance of any horizontal run of pipe. If the water is lower, you need a submersible pump or a pump with a remote ejector.

## If the pump only hums and does not turn

A motor that hums without turning has either seized after standing idle or has a failed start capacitor. Switch it off at once: in this state the winding overheats within minutes. Have an electrician or a service centre check the capacitor and motor.

> Never let a pump run without water: dry running quickly wears out the seals and the impeller. Dry-run protection can be fitted separately — it switches the pump off when the water runs out.

If the pump delivers water but starts too often, see [“Pump keeps switching on and off”](https://watertrade.com.ua/en/articles/article/nasos-chasto-vklyuchaetsya). Check valves, pressure switches and dry-run protection are in [pump controls](https://watertrade.com.ua/en/catalogue/nasosy/avtomatika-dla-nasosov).

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