How to Prime a Water Pump (Surface and Jet Pumps): Step-by-Step Guide 2026

Oct 13, 2026

Buy More Mall Kenya

A surface or jet pump can only push water once its casing and suction pipe are full of water. If air gets in, the pump spins but nothing comes out. Filling it with water to drive the air out is called priming, and it takes a few minutes.

Quick answer: Switch off the pump, open the priming plug on top of the casing, pour clean water in until the casing and suction pipe are full and no more bubbles rise, close the plug tightly, then start the pump with the outlet tap slightly open. If it loses prime again, check the foot valve (from KSh 700) and every suction joint for air leaks. Submersible pumps sit under water and do not need priming.

Which Pumps Need Priming?

Pump type	Needs priming?
Surface centrifugal pump	Yes, before first use and whenever it loses prime
Self-priming jet pump	Fill the casing once; it then clears small amounts of air itself
Submersible pump (borehole, well, tank)	No, it sits under water
Booster pump fed from a raised tank	Usually fills by gravity; bleed any air

DAVEY JETPLUS JY350 – price in Kenya — DAVEY JETPLUS JY350
**KSh 24,500**

PEDROLLO JSW1A – price in Kenya — PEDROLLO JSW1A
**KSh 23,500**

PEDROLLO JSW2A – price in Kenya — PEDROLLO JSW2A
**KSh 44,000**

Automatic Pump Pressure Controller and Switch Kit – price in Kenya — Automatic Pump Pressure Controller and Switch Kit
**KSh 6,000**

PEDROLLO EASY PRESS PUMP CONTROLLER – price in Kenya — PEDROLLO EASY PRESS PUMP CONTROLLER
**KSh 24,000**

Foot Valve 1 Peg – price in Kenya — Foot Valve 1 Peg
**KSh 700**

Some photos are reference images of the product type, used under open licences. Image credits are on each product page.

Product	Use	Price
DAVEY JETPLUS JY350	Self-priming jet pump for wells and tanks	KSh 24,500
PEDROLLO JSW1A	Self-priming jet pump	KSh 23,500
PEDROLLO JSW2A	Larger self-priming jet pump	KSh 44,000
Automatic Pump Pressure Controller and Switch Kit	Pressure control with dry-run protection	KSh 6,000
PEDROLLO EASY PRESS PUMP CONTROLLER	Pump controller with dry-run protection	KSh 24,000
Foot Valve 1 Peg	Keeps water in the suction pipe	KSh 700

How to Prime a Surface or Jet Pump Step by Step

Switch off and isolate the pump at the socket or isolator.
Close the delivery (outlet) valve partly.
Remove the priming plug on top of the pump casing.
Pour clean water in slowly until it overflows and no more bubbles appear. A long suction pipe takes more water.
Refit the plug tightly with thread tape if it weeps.
Switch on and open the outlet slowly. Water should come within a minute.
If only air comes out, switch off after a minute and repeat. Never let it run dry for long.

Do not run a pump dry: the shaft seal is cooled by water and can burn out within minutes. A pump controller with dry-run protection switches the pump off automatically.

Why Does My Pump Keep Losing Prime?

Cause	Fix
Leaking or stuck foot valve	Clean or replace the foot valve
Air leak on the suction pipe or joints	Re-seal joints with thread tape or hemp; tighten unions
Suction lift too high	Move the pump closer to the water level
Suction pipe smaller than the pump inlet	Use the full inlet size
Low water level in the tank or well	Keep the foot valve well under the water

Still no water after priming? See water pump not pumping water: causes and fixes.

Worked Example: A Jet Pump on a Shallow Well

A family pump lifts water from a shallow well to a roof tank. After the dry season the pump runs without water. They lower the suction pipe so the foot valve is well under water, clean the foot valve, prime the casing until no bubbles rise and add a dry-run controller so the pump switches off if the well drops again.