How To Prime a Pool Pump

WRITTEN BY:  Inyo Pools

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When a system is fully primed, the system components, pipes, pump, filter etc., are filled with water and the pool pump is able to suck water from the pool and push it back into the pool through pool returns. Priming a pool pump involves purging air from the pumping system and filling the water lines and pump with water. The number of steps required to prime your pool pump depends on the amount on water in the suction side of the lines - water coming from the pool to the pump. If you are installing a new pool system, there is no water in the lines, and you may have to repeat these steps several times. If you are adding or replacing components into the pumping system (like a heater), there will still be some water in the lines and priming will be simpler. The following procedure assumes that you have no or little water in the system. Visible indications of low water are no or little water in the pump strainer box, and a low pressure reading on the pool filter pressure gage.

Things You'll Need


Step by Step


Step 1

If the pool pump is running, your first step is to turn off the power to the pool pump. For maximum safety turn off the power at the circuit breaker to the motor.

Step 2

The suction diverter valve allows you to shut off water from the skimmers or from the main drain. Generally you cannot shut off both. To prime the system in steps, move the diverter valve so that the off side of the lever is pointing to the main drain side. Now water can only flow from the pool skimmer lines. Note: if you are only adding a component to an existing system, water will still be in the lines and you can probably re-prime the system by opening the skimmer and main drain lines at the same time (lever is halfway between skimmers and main drains).

Step 3

Next you will have to relieve any pressure that remains in the pool pump and water lines. To relieve pressure turn the air relief valve on top of the pool filter counter clockwise. You will hear air releasing as you see the pressure on the pressure gauge go to 0 psi. Leave this relief valve open.

Step 4

Open the lid to the pool pump strainer box. To open up the strainer box, 1-turn the two knobs on top of the strainer lid counter-clockwise and 2- swivel the knobs down away from the lid. Note: Some strainer lids screw on instead of having knobs. In these cases twist the lid counter-clockwise to remove the lid off the top of the strainer box.

Step 5

Remove the pool pump strainer basket and clean out any debris that has accumulated. Replace basket.

Step 6

Fill the pool pump strainer box with water using a garden hose or bucket.

Step 7

Replace the strainer lid carefully to ensure a good seal. Hand tighten only. If your pool pump has knobs, tighten them evenly by hand. Do not use tools to tighten the lid.

Step 8

Ensure that the diverter valve to the pool return is open. This will allow the pool pump to discharge water to the pool. If this is not open, excessive water pressure that builds up during pump operation may damage parts of the pumping system and may be dangerous.

Step 9

Restore power to the swimming pool pump.

Step 10

Check the water flow through the strainer box. Water should flow freely in 30-60 seconds.

Step 11

The air relief valve should still be open. As the pressure builds, air will be released through the relief valve. When water starts to spray out of the valve, turn the valve clockwise to close it.

Step 12

If water isn't flowing freely in 30-60 seconds, repeat steps 1 - 10: turn off the pump, bleed off the pressure, reopen the strainer, refill the strainer, and close the lid. Then turn on the pump. You may have to repeat these steps several times to purge the air from the line.

Step 13

When water is flowing through the pool skimmer lines, slowly open the main drain line at the diverter valve. Open the relief valve to allow air in the main drain line to escape. Again water should flow freely in 30-60 seconds. Close the relief valve. If you don't see pressure building on the pressure gauge and a full strainer box, repeat steps 1 -10.

Step 14

After the system is fully primed, move the diverter valve halfway between skimmer and main drain for normal operation.

Step 15

If, after repeated attempts, you cannot prime the system successfully, your system has a major leak or blockage. This problem must be resolved before you can prime the swimming pool system.


(1 to 40 of 105)

Inyopools  Posted: 03/20/2017 10:01 AM  Inyo Product Specialist

Bonnie - Try blowing the clog out with a drain cleaner bladder. It's simpler, cheaper and most people have had good success with them. It’s most effective if you insert it at the pump going back to the pool. Any hardware store sells these bladders.

Bonnie  Posted: 03/16/2017 11:13 AM 

how can you remove problem in clogged pipe? Cannot prime pump, have tried all you have suggested.

Inyopools  Posted: 11/18/2016 12:10 PM  Inyo Product Specialist

Alex Z. - Yes, you will have to replace the impeller from the old motor and reinstall it on the new motor. For a step-by-step procedure on replacing a motor, see our guide on "How To Replace the Motor on Your Pool Pump". Remember to buy an replace the motor shaft seal.

Alex Z.  Posted: 11/16/2016 21:11 PM 

I believe that my motor just burned. It's been acting up for about 4 months know. it would struggle to start every time (would make a noise like it's about the start and then it shuts off again). Finally today it was doing it for few hours while i was at work and still kept doing it when i came home. It smelled like something burned and it was very hot (to the point that i had black marks on my sand filter thats sitting next to it). I purchase same exact motor online and will be replacing it this weekend hopefully. My question is, since i never did this before, do i need to remove impeller as well, or i can only remove the motor, put the wires the way they were and proceed with priming process? Thank you in advance

Inyopools  Posted: 09/16/2016 12:11 PM  Inyo Product Specialist

Dom Fiocco - I would shut off the valve to the solar system until the pump is primed than slowing open the solar valve.

Dom Fiocco  Posted: 09/14/2016 17:07 PM 

My pool pump won't prime if the valve to our rooftop solar system is open. Any ideas on how to resolve?

Inyopools  Posted: 08/15/2016 14:09 PM  Inyo Product Specialist

Rick - Thanks for the priming tip. It sounds like a great solution for anyone with a significantly elevated pump.

Rick  Posted: 08/14/2016 18:43 PM 

I tried everything and couldn't get mine primed and FINALLY found a trick that worked that I though worth sharing. Forcing water into the skimmer intake (the inlet from your main drain should probably be closed). I had stuck a hose in it before and still couldn't get it to work, so I wrapped cardboard and tape around the hose to make the hose fit tightly into the inlet from the skimmer, which was a little bigger than the hose. Cranked the water all the way, forcing it up to the pump, which in my case was about 4 feet above the water level. Turned on the pump and it caught within seconds. I am soooo glad to finally find a way that works.

Inyopools  Posted: 08/01/2016 14:37 PM  Inyo Product Specialist

confused - No, you should only add water to the strainer basket for a couple of minutes. It will not fill completely since you have an open system and some water is draining out to the pool. If you are having trouble priming the pool, close off all but one of the suction lines to the pool. Then open the others back up after the pump is primed. Check to make sure that you don't have leaks in the suction lines that are preventing your pump from priming. See our guide on "How to Identify and Correct Air Leaks".

confused  Posted: 07/31/2016 13:25 PM 

I am trying to prime my pump. Is it possible that it could take hours to fill the lines through the filter basket? Should the water lines be open or closed? I have them open.

Inyopools  Posted: 07/02/2016 10:36 AM  Inyo Product Specialist

WW - I have not seen a pump operate up and down like that. If it only happens on the Backwash and Rinse modes, the problem is probably in the Waste port of the filter. Make sure that port and the hose from it is not partially blocked. Check the spider gasket in the valve to make sure it is intact.

WW  Posted: 06/30/2016 19:15 PM 

I just hooked up an Intel 14" 2800 gph sand filter pump. Back washed, and rinsed fine. In the filter mode however the pump seems to rev up and down and the psi goes up and drops right along with it. It's not dramatic, maybe from 10 to 4 psi back and forth. Any reason why it would do this in filter mode but run smooth in backwash and rinse?

Inyopools  Posted: 05/24/2016 15:39 PM  Inyo Product Specialist

Scott72 - Concentrate first on what you changed. If you pulled the strainer cover off to clean the basket, make sure the cover O-ring is in place. Sometimes, if the O-ring is old and stretched out, it may poke out when you are closing the cover leaving a big air hole. If that is good, try filling the pump trap with water from a hose. You won't be able to fill it but you will put some water in the pipe to the pool. Leave the multiport valve in filter until the system is primed. Turn the pump off and switch to backwash, then switch the power back on.

Scott72  Posted: 05/23/2016 17:30 PM 

I've got an older pool with a Heyward S200 sand filter. I don't have a diverter valve from the main line to the skimmers; just the pump selector lever (backwash, rinse, filter, etc.). According to the instructions on the pump, I am supposed to prime it, then run it on backwash until I had a steady flow of water, then rinse, then filter. I had this thing running great yesterday, opened the basket to empty it, and now can't get it to prime to save my life. Am I missing something? Please help! Thank you!

Inyopools  Posted: 05/20/2016 9:42 AM  Inyo Product Specialist

check valve - The check valve should keep the water from flowing back into the pool after the pump is shut off. So priming would be faster.

Anonymous  Posted: 05/18/2016 0:15 AM 

How would this work if there is a check valve on the suction side of the pump?

Anonymous  Posted: 07/29/2015 13:15 PM 

Worked great. Thanks.

Inyopools  Posted: 07/24/2015 12:28 PM  Inyo Product Specialist

prime - Generally you will see a little water/air at the top of the pump basket while the pump is running. I have seen a perfectly smooth top where it looks like no water is flowing but this is an exception. The discharge from the pump would have to match the water coming in on the suction side of the pump. If you have a lot of air in the pump basket (Cavitation) you either have a suction air leak or your pump may be too large and it is discharging the water faster than it can pull it in.

Anonymous  Posted: 07/23/2015 23:37 PM 

should you see water in your pool pump when its running

Inyopools  Posted: 11/04/2014 9:00 AM  Inyo Product Specialist

creepy backwash - Sound like you don't have sufficient water flow in the filter setting. If you haven't replaced the sand in your filter in the last 5 years, I would do that first. See our guide on "How To Correct Low Water Pressure in Your Pool System" for other suggestions.

Anonymous  Posted: 10/30/2014 4:05 AM 

My creepy only sucks of backwash. How do I correct this please

Inyopools  Posted: 07/11/2014 9:48 AM  Inyo Product Specialist

Bigredthingy - Try placing Tupperware covers over the input and return holes on the inside of the pool. The pool water pressure should hold them against the holes.

Bigredthingy  Posted: 07/11/2014 9:25 AM 

We already have our pool full and a pump and cartridge filter hooked up, but old cartridge leaks in too many places! I have a new pump and cartridge filter system that we want to hook up and don't know how to stop all the water from pouring out on us while we exchange the equipment! Please, help!

Inyopools  Posted: 06/17/2014 10:56 AM  Inyo Product Specialist

have know clue - Hard to say. Go back and look at everything you might have changed to make sure it is the same as it was - assuming your system was running well before you painted. Check the voltage connections and readings to make sure your voltage is correct. This problem is characteristic of low voltage to the pump.

have know clue  Posted: 06/16/2014 22:03 PM 

my pool was drained five month . was repainted and filled up, primed the pump, and flipped the switch pump came on for twentyfive sec,then me somebody

Inyopools  Posted: 06/13/2014 8:57 AM  Inyo Product Specialist

Tavo - If you tried opening the main drain after you had the system running with the skimmers, and you lost prime, it sounds like you have a leak in the pipe coming from the main drain to the pump. Try soaping up any visible connections between the diverter valve and the main drain to see if any bubbles are sucked into a leak. If not, your leak may be underground.

Tavo  Posted: 06/12/2014 0:00 AM 

I have not been able to prime my pump using the main drain. I let the water run inside the pump basket for at least 20 min but if never filled up. I gave up on the main drain and the pump it's running once I changed to skimmers only. I have try opening the slowly to the main drain but have not have success. My concern is that I ran the water to the main drain for a long time and no luck.

Inyopools  Posted: 04/23/2014 8:02 AM  Inyo Product Specialist

Golden-Hawk - We only sell the rubber flapper as a kit with this valve.

Inyopools  Posted: 04/23/2014 7:58 AM  Inyo Product Specialist

Golden-Hawk - No, it will not hurt the pump to prime for 5 minutes.

Golden-Hawk  Posted: 04/21/2014 11:29 AM 

I am using 2" Jandy Check valves to prevent back flow< Is it possible to buy just the rubber flapper instead of the $30.00 kit?

Golden-Hawk  Posted: 04/21/2014 11:24 AM 

Hello, I have a 30k pool with dual mains and dual skimmers. The pump is app. 6' above the water line.Both Mains and skimmers have Jandy ck valves to slow run back. The pump is on a auto timer and after several hours of off time, its takes about 5 min to prime the pump. Is this going to damage the pump? Thx,Ken

Inyopools  Posted: 04/21/2014 10:45 AM  Inyo Product Specialist

HH - Most pool systems will drain back into the pool when the pump is shut off. If your pump is higher than normal above the pool surface it will drain more. One way to stop this backflow is to put a check valve in your system after the pump.

HH  Posted: 04/18/2014 23:44 PM 

my filter set up always loses the water when shut off, i have to reprime every day.
I can hear buble noise inside the filter, that means some air is entering it and some water goes to the pool.

I suspect there's a leak that the air gets in - but i see no leak at all when the system is running?


Inyopools  Posted: 03/27/2014 9:23 AM  Inyo Product Specialist

Larry - We generally recommend a pump size of 1 HP for your pool size and configuration. I would not install a pump less than 3/4 HP.

Anonymous  Posted: 03/23/2014 1:20 AM 

Larry I am replacing my old 3/4 hp pool pump to a pentair whisperflow ee 1/2 hp can the new pentair handle my 20,000 gal pool and pump water to my solar panels on my 2 story house?

Stephen  Posted: 03/19/2014 8:01 AM 

It worked. I really appreciate the help. I know where I will be purchasing all my pool needs now.

Inyopools  Posted: 03/18/2014 11:44 AM  Inyo Product Specialist

Stephen - I talked to the Hayward rep and he suggests changing the prime setting in your Ecostar pump from "auto prime" to "3 minutes". Please let me know if this works. Thanks

Stephen  Posted: 03/16/2014 14:39 PM 

I have a Hayward Ecostar pump and a Hayward filter. For some reason the pump will not prime in filter mode. It will prime in backwash, rinse, recirculate...just not in filter. Any suggestions?

Inyopool  Posted: 11/06/2013 16:45 PM 

Ed - Depending on the height of you pump relative to your pool level, you may have drained most of the water from your suction pipes. Fill the strainer basket with your hose for 5 minutes. Secure the strainer cover and try running your pump again. It might take 5 minutes to prime fully.

Ed  Posted: 11/03/2013 19:42 PM 

I just drained and cleaned out my De filter. Does it take longer to prime the pump after that? I've tried several times but can't get water to flow.