Priming fills the hose with water so suction starts when ready
Priming means filling your vacuum hose with water before you turn on the pump. Without priming, air gets trapped in the hose and blocks suction — you'll run the pump for minutes and get nothing. A primed hose pulls water the moment you submerge the head, which saves time and prevents air locks that can damage the pump.
The process takes less than a minute and requires only the hose, the pump, and your pool. You do not need special tools or chemicals. Most pool owners prime by hand before every cleaning session.
Key Takeaways
- Priming means filling the hose with water before turning on the pump so air does not block suction.
- The hand-over-end method works for most hoses: hold one end above water, submerge the other, and let gravity pull water through.
- If your pump has a prime valve or air relief valve, open it while filling to let trapped air escape faster.
- A primed hose should feel heavy and show no air bubbles when you hold it underwater.
- If priming fails and air stays in the line, check for cracks in the hose or loose connections at the pump.
The hand-over-end method works for most residential pools
Disconnect the hose from the pump if it is already attached. Hold one end of the hose above the water surface and submerge the other end completely in the pool. Water will begin to flow into the submerged end and travel toward the end you are holding. Keep the submerged end deeper than the end in the air — gravity does the work.
Once water reaches the end you are holding (you will see it emerge or feel the hose become heavier), quickly place your thumb over the opening to trap the water inside. Keep your thumb in place while you reconnect the hose to the pump. The water stays trapped inside, and suction begins the moment you turn on the pump.
This method works because water seeks the lowest point. The deeper the submerged end, the faster water fills the hose. If your pool is very deep or your hose is very long, this can take 30 to 60 seconds — that is normal.
Using the pump's prime valve or air relief valve speeds the process
Many pool pumps have a prime valve or air relief valve on top of the pump housing. This valve lets trapped air escape while you fill the hose. If your pump has one, open it before you begin priming.
Submerge the hose end in the pool as before. Once water starts flowing into the hose, keep the valve open. You will see air bubbles come out of the valve — that is the trapped air leaving the system. Once the bubbles stop and only water comes out, close the valve and reconnect the hose to the pump. The hose is now fully primed.
Check your pump's manual to find the valve location and which direction opens it. Some valves are small knobs, others are levers. Closing it too tightly can crack the valve, so turn it only until it stops naturally.
Check for leaks and cracks before priming
Before you prime, inspect the hose for visible damage. Look for cracks, splits, or soft spots along the entire length. Flex the hose gently with your hands — it should feel firm and uniform. If you see cracks or the hose feels mushy in one spot, it will not hold prime and should be replaced.
Also check the connection points where the hose meets the pump and the vacuum head. Tighten any loose fittings by hand. A loose connection lets air in and breaks the seal, so priming will fail even if the hose itself is sound.
If the hose is old and has been sitting in the sun for months, it may have become brittle. Brittle hose cracks easily when you bend it. If you suspect age damage, replace the hose before attempting to prime.
What to do if the hose will not stay primed
If water drains out of the hose after you disconnect it from the pump, or if suction fails after a few seconds of running, air is leaking back in. This usually means either a crack in the hose or a loose fitting.
Start by checking every connection point again. Tighten the fitting where the hose meets the pump, and tighten the fitting where the hose meets the vacuum head. Hand-tight is usually enough — do not use a wrench unless the manual says to.
If tightening does not work, hold the hose up to a light and look through it for small cracks you may have missed. Even a pinhole leak will break the prime. If you find a crack, patch kits exist for small holes, but a hose with multiple cracks should be replaced. A new hose costs less than repeated repairs and works better.
Priming in cold weather or with very long hoses
Cold water is denser than warm water and flows more slowly through the hose. In winter or early spring, priming may take two to three minutes instead of one. This is normal — be patient and keep the submerged end deeper than the other end.
Hoses longer than 50 feet take longer to prime because there is more air to displace. If your hose is very long, use the pump's prime valve if it has one — it cuts the time in half by letting air escape while water fills the line.
Some pool owners with long hoses keep a bucket of pool water nearby and pour it into the hose opening while the other end is submerged. This speeds filling without requiring you to hold the hose at an angle for several minutes. Either method works.
Frequently Asked Questions
Can I prime the hose while it is connected to the pump?
Yes, if your pump has a prime valve. Open the valve, submerge the hose end in the pool, and let water flow until air stops coming out of the valve. Then close the valve and turn on the pump. If your pump has no prime valve, disconnect the hose first — it is faster and easier.
What if water comes out of the pump when I open the prime valve?
That is normal. The prime valve releases water and air that is already in the pump housing. Place a bucket underneath to catch the water, or open the valve over the pool. Once only water comes out and no more air bubbles appear, close the valve.
Do I need to prime the hose every time I vacuum?
Yes, every time. If the hose sits disconnected overnight or between uses, air enters and breaks the seal. Priming takes less than a minute and prevents the pump from running dry or losing suction partway through cleaning.
Can I use a wet/dry shop vacuum to prime the hose instead?
No. Shop vacuums are not designed for pool water and can be damaged by chlorine and pool chemicals. Use only the pool pump to create suction. The hand-over-end method is the safest and most reliable way to prime.
Why does the hose lose prime after I turn off the pump?
Water drains back into the pool when the pump stops. This is normal. You will need to prime again the next time you use the vacuum. If water drains out while the pump is still running, you have a leak — check for cracks or loose fittings.