How to Prime a Pool Pump: Step-by-Step Guide
Pool pump priming involves ensuring water flows into the system for suction and circulation. Typically, this process concludes within 30 to 60 seconds under optimal conditions. Otherwise, a blockage likely interrupts it, often in an unexpected location like the check valve or strainer basket. A failed priming attempt usually indicates air has infiltrated these areas, causing the pump to fail or trip the breaker. You’ll want to inspect these components before replacing any parts or calling for service.
A pool pump that fails to prime is almost always missing water on the suction side. The fix: fill the pump basket with a garden hose, seat the lid O-ring, and restart. We see most pumps prime within 30-60 seconds using this method.
Before you prime: checklist (do this first)
Skipping the pre-prime checklist is the most common reason priming fails. Address each item before adding water or restarting the pump.
- Water level: Pool water must be above the middle of the skimmer opening (the skimmer throat). If the water level is too low, the skimmer pulls air instead of water and the pump can’t prime regardless of what you do. Add water first if needed.
- Baskets: Remove and clean both the skimmer basket and the pump basket. Clogged baskets restrict flow even when the pump is running and prevent successful priming.
- Valves: All suction and return valves must be fully open. A partially closed valve creates an air lock that blocks prime.
- O-ring: Inspect the pump basket lid O-ring. It should be pliable and seated in its groove with no cracks or flat spots. Apply a small amount of Magic Lube (Teflon-compatible) if the O-ring is dry. Replace it if cracked. A damaged O-ring is the single most overlooked cause of prime failure.
- Filter valve position: If you have a sand or D.E. filter with a multiport valve, make sure it’s set to FILTER — not BACKWASH or RECIRCULATE.
If you’re starting your pool after winter, check our guide to opening pool for the season for the full startup sequence before attempting to prime.
This guide also assumes your pump turns on and runs. If the pump won’t turn on at all, that’s a different issue — see our pool pump troubleshooting guide.
.. / this guide isn’t for you if..
:
- You’re priming the pump after the pool opening for the season
- You’re priming after a repair (new seal, new pump head, or wet end work)
- The pump ran dry and lost suction
This guide isn’t for you if:
- The pump keeps losing prime repeatedly within minutes of starting — that’s an air leak problem, not a priming issue. See pump won’t prime or keeps losing prime for that diagnosis.
- The pump won’t turn on at all — see pool pump repair and the electrical troubleshooting guides.
Video guide
Video: “How to PRIME a Swimming Pool Pump” by Hallmark Pool Supplies
How to prime a pool pump (self-priming pump)
Most in-ground pool pumps are self-priming, meaning they’re designed to pull water up from below and create their own suction — but they need a water-filled starting point to do it.
What you need: Garden hose, flathead screwdriver
Turn off the pump by tripping its breaker or switching it off at the timer unit. Open the basket lid by rotating it counterclockwise. Occasionally, you must press it down simultaneously. Next, immerse a garden hose in the basket until water reaches the top of the housing. Replace the lid and hand-tighten it firmly to seat the O-ring without overdoing it.
Bottom line.
Once everything is set, start the pump again. Observe through the transparent lid; within 30 to 60 seconds, water should flow into the basket and circulate. Should the basket remain empty after a minute, shut down the pump, refill with the hose, then retry. Systems with significant air locks might need up to three attempts.
Finally, inspect return jets for air bubbles, they should dissipate within 2 to 3 minutes once proper priming is achieved.
Nothing fancy.
For a detailed walkthrough with photos, the INYOPools priming guide{:target=“_blank”} covers several pump model variations.
What success looks like: The pump basket is full of water with no air visible through the lid. The pressure gauge on the filter rises to its normal operating range (typically 8-15 PSI for a clean filter). You feel strong, steady flow from the return jets in the pool.
Systems with significant elevation between the pool and the pump (the pump is installed much higher than the water level) may need extra attempts because the pump must overcome more air column. This is normal — just refill and retry.
Priming an above-ground pool pump
Above-ground pool pumps aren’t self-priming in the same way as in-ground pumps because the pump sits above or beside the pool rather than below. Gravity doesn’t help pull water up to the pump.
For Intex and Bestway cartridge filter systems (the most common above-ground pump setups):
Close the return valve if present, then open the suction valve fully. Next, remove the inlet port plug from the pump body and fill it with water through the inlet port using a hose until water starts to run out. Reinstall the plug afterward. Then, open the return valve and start the pump, ensuring it doesn’t trip the breaker.
Above-ground pumps may require more patience. If the suction line is long or has several fittings, it holds more air and takes longer to clear. We recommend keeping the pump running (watching for overheating) for up to 3 minutes before turning off to refill.
For above-ground pump installation and setup guidance, Hayward pump support{:target=“_blank”} provides manuals for their aboveground pump line.
When the pump primes then quickly loses water
If the pump basket fills and the pump appears to prime, but then the basket empties within a minute or two, there’s an air leak on the suction side pulling air back into the system.
Most common causes:
- O-ring not sealing: The pump lid O-ring is letting air past. Try lifting and reseating the lid, or applying more Magic Lube. If the O-ring is cracked or misshapen, replace it ($5-$10).
- Check valve not holding (elevated systems): Systems where the pump sits higher than the pool often have a check valve on the suction line. When the valve leaks, the water column falls back toward the pool when the pump slows or stops. The pump must re-prime every cycle.
- Suction line air leak: A crack, loose union, or failed fitting on the suction side allows air to enter while the pump is running. Use the shaving cream test: apply foam to suction joints while the pump runs. The foam disappears where air is being pulled in.
Consider pool pump seal replacement if you find the shaft seal area is weeping water, as a failed shaft seal can also allow air to enter on some configurations.
FAQ
How long does it take to prime a pool pump?
A pool pump in good condition with no air lock primes in 30-60 seconds. If the suction line has a large air pocket (common after winter storage or after opening union fittings), expect 2-3 attempts of 60 seconds each. If the pump hasn’t primed after 5 minutes of total run time across multiple attempts, work through the pre-prime checklist again — water level, baskets, O-ring, and valve positions account for nearly every failure.
Why do I have to prime my pool pump every time?
Needing to manually prime at every startup isn’t normal for an in-ground self-priming pump. It indicates an air leak somewhere on the suction side that allows the water column to fall back toward the pool when the pump shuts off. Common culprits: cracked lid O-ring, loose union on the suction line, or a leaking check valve on elevated systems. See our guide on pump won’t prime or keeps losing prime for a systematic diagnosis.
Can I run my pool pump without priming it?
Check this before starting up your pump: Ensure it has enough water to prevent the impeller and shaft seal from drying out. This can cost $30-$80 for repairs or replacements. The impeller and shaft seal need water to function. Without it, they overheat and fail in just minutes. Run dry pumps are a costly mistake that’s easily avoided by priming your system first.
My pump basket fills but then empties when I turn it off — is this normal?
Yes, this is normal for most self-priming pump setups. When the pump stops, the water in the basket and suction line can fall back toward the pool — especially on systems without a check valve. This is only a problem if the basket also empties while the pump is running (indicating a suction-side air leak) or if the pump can’t prime at the next startup without manual assistance.
Pay attention.
For general pool equipment startup guidance during the season, including filter backwash timing and pressure baselines, see our pool filter maintenance guide.
Worth checking.
For more help with your pump system, see our complete pool pump troubleshooting guide and the full troubleshooting framework.
For variable speed pump startup sequences and priming considerations, Pentair pump manuals{:target=“_blank”} cover their IntelliFlo and SuperFlo VS models in detail.