Why Priming a Water Pump Matters
A water pump can't move water on its own — it needs to be filled with water first to create the suction necessary to draw more water in. This process is called priming. Skipping it can cause your pump to run dry, overheat, and fail prematurely. Whether you have a shallow well jet pump, a pool pump, or a garden booster pump, priming is an essential first step.
In this guide, we'll walk you through how to prime the most common pump types step by step.
Do All Pumps Need to Be Primed?
Not all pumps require manual priming. Here's a quick breakdown:
- Submersible pumps — No priming needed. They sit underwater and are always surrounded by water.
- Self-priming pool pumps — Designed to prime themselves, but still need water in the pump housing on first use.
- Shallow well jet pumps — Must be manually primed before first use and after any dry-run situation.
- Garden/booster pumps — Usually require priming if they've been drained or run dry.
How to Prime a Shallow Well Jet Pump (Step-by-Step)
Shallow well jet pumps are the most common type that requires manual priming. Follow these steps:
What You'll Need
- A bucket of clean water (at least 1 gallon)
- A flathead screwdriver or wrench
- Teflon tape (if resealing fittings)
Step 1: Turn Off the Pump
Always make sure the pump is completely powered off before you begin. Disconnect it from the power source if possible.
Step 2: Locate the Priming Plug
Find the priming plug on top of the pump housing. It's usually a large bolt or cap. Use a wrench or screwdriver to remove it.
Step 3: Fill the Pump Housing with Water
Slowly pour clean water into the priming hole until the housing is completely full and water starts to overflow slightly. This ensures there are no air pockets inside.
Step 4: Replace the Priming Plug
Screw the priming plug back in firmly. Wrap the threads with Teflon tape first if you notice any leaks.
Step 5: Turn On the Pump
Power on the pump and listen for it to start drawing water. It may take 1–2 minutes for the pump to fully prime and build pressure. You should hear the motor tone change as water begins to flow.
Step 6: Check for Leaks and Pressure
Once water is flowing steadily, check all connections for leaks. Your pressure gauge should rise to the normal operating range (typically 30–50 PSI for home systems).
✅ Recommended: FOTING 1.5HP Shallow Well Pump with Pressure Tank — features automatic pressure control so you don't have to reprime after every power outage.
How to Prime a Self-Priming Pool Pump
Self-priming pool pumps are designed to pull air out of the suction line and replace it with water automatically — but they still need water in the pump basket on first startup.
Step 1: Turn Off the Pump
Switch off the pump and close the suction and return valves.
Step 2: Open the Pump Lid
Unscrew the clear pump lid (strainer basket cover) by hand or with a lid wrench.
Step 3: Fill the Strainer Basket with Water
Pour water directly into the strainer basket until it's full. This gives the pump enough water to begin the self-priming process.
Step 4: Replace the Lid and Open Valves
Screw the lid back on tightly. Open the suction valve fully, and open the return valve slightly.
Step 5: Turn On the Pump
Power on the pump. Watch the clear lid — you should see water filling the basket within 1–3 minutes. Once the basket is full of water (no air bubbles), the pump is primed.
Step 6: Open the Return Valve Fully
Once primed, open the return valve to full flow and check that water is circulating properly.
✅ Recommended: FOTING 1.5HP Self-Priming Pool Pump 6000GPH — built-in self-priming design makes startup fast and easy for above-ground and in-ground pools.
How to Prime a Submersible Sump Pump
Good news: submersible pumps don't need priming. Because they operate fully submerged in water, they're always ready to run. Simply place the pump in the water, plug it in, and it will start pumping immediately.
However, never run a submersible pump out of water — this can damage the motor seals within minutes.
✅ Recommended: FOTING 1HP Submersible Sump Pump 4600GPH — handles both clean and dirty water, no priming required.
Common Priming Problems & How to Fix Them
Pump Won't Prime (No Water Flow After 3+ Minutes)
- Check for air leaks in the suction line — even a small gap can prevent priming
- Make sure the foot valve (check valve) at the bottom of the suction pipe is not stuck open
- Verify the suction pipe is not clogged with debris
- Ensure the pump housing was completely filled with water before starting
Pump Loses Prime Repeatedly
- Inspect all pipe joints and fittings for air leaks
- Check the foot valve — it may need replacement
- The suction lift may be too high (shallow well jet pumps typically max out at 25 feet of suction lift)
Pump Hums But Doesn't Move Water
- The impeller may be air-locked — turn off the pump, re-prime, and restart
- Check that all valves are open
Tips to Avoid Priming Problems
- Install a foot valve at the bottom of your suction pipe to keep water in the line when the pump is off
- Use FOTING 1" Suction Hose Kit with Check Valve for a complete, leak-free suction setup
- Always prime before the first use and after any extended period of non-use
- Keep a bucket of water near the pump for quick re-priming if needed
Final Thoughts
Priming a water pump is a simple but critical step that protects your equipment and ensures reliable performance. Whether you're setting up a shallow well jet pump for home water supply, getting your pool pump ready for summer, or deploying a sump pump in your basement, following the right priming procedure will save you time and costly repairs.
Browse FOTING's full range of pumps at JUNHE PUMPS — built for reliability, easy setup, and long-lasting performance.