Low pressure is a pool term that is often used to describe weak jets as well as a low PSI reading on the filter’s pressure gauge. High PSI readings will also cause low water pressure. A low or high PSI reading is anything outside the normal operating pressure of the filter. Weak jets, air bubbles, slow pool cleaners and weak water features are obvious signs of low pressure. This guide addresses the common causes of low water pressure in a pool.
paul Posted: 5/13/2018
I had 2 pressure problems. The gauge showed 15 all he time, even closing the outlet valves to the pool. The pressure going to the pool was very low, auction seemed good. The heater also wouldn't work as the pressure switch wouldn't close. Tried all the pump/Line checks.... Almost bought a new switch. Then I finally saw the inlet arrow to the heater and just swapped the 2 houses to the heater and VOILA!!! FULL PRESSURE, and the heater worked properly now as well.Reply
Inyopools Posted: 5/9/2018
Hello Andrew - There should be a diverter valve near the pump that controls the flow from the skimmer and main drain. You'll have to test the valve to see which lines it is controlling.Reply
Andrew Posted: 5/9/2018
Thanks for the quick reply. You guys are amazing! As far as the main drain suggestion, I am not quite sure what that means. If I am not mistaken, the main drain is at the bottom of the deep end. How would one open the main drain slightly? Thanks again.Reply
Inyopools Posted: 5/9/2018
Hello Andrew - A leak detection company would have to be called in if it is underground. I would exhaust every other avenue before you go that route. Try opening up the main drain slightly. This will ensure that the pump is receiving enough water while you are vacuuming. Make sure the vac hose is clear of any air before you vacuum. Clean the filter and make sure the PSI on the gauge is staying at the normal operating range. Lastly, check for any suction side air leaks; pump lid o-ring, valves, couplings, unions.Reply
Andrew Posted: 5/9/2018
I have the same problem as Florida Pool Boy below. Complete loss of pressure only when vacuuming. I had the same problem when I opened last year, and it gradually resolved itself over the course of the season. But I have the same thing happening this season and I am unable to vacuum at all. I have an inground concrete pool. I am worried that the pressure change is causing an air leak somewhere underground because I can't see anything wrong above ground. Any recommendations for a next step? Thanks!Reply
Inyopools Posted: 5/4/2018
Hello Eric - If the pool water is not clear, your filter is probably filling up quickly and that's why the water flow is dropping. Check out our article titled "Why are My Pool Jets Not Working?"Reply
Eric Posted: 5/3/2018
I have a loss of flow only when in the filtration setting on the multiport valve. It is fine and water flowing strong when in the recirculating mode. Had this problem last year. Replaced the multiport before opening pool this year. Still the problem. I change sand yearly. Checked all orings. No leaks. Took apart the laterals/ fingers and scrubbed them out with a toothbrush and found nothing. PVS pipe in center is fine. Pump is replacement only 1 1/2 yr old. Also it doesn't change sound or speed when I change settings either. Doesn't sound like and change. Pressure or flow will slow in hours. Odd thing is that if I back wash and rinse a few minutes it corrects problem for about 5 hrs. AS I said new sand yearly, new port and laterals are fine. What gives!Reply
Inyopools Posted: 5/2/2018
Hello FloridaPoolBoy - When the hose is plugged into the skimmer, there is a reduction in flow and the suction pressure will build. This will amplify potential problems in the system. Check the pump lid o-ring. If it is cracked or disfigured, replace it. Try lubricating it if it looks ok. Also, check the hose going from the pool to the intake of the pump. Increased suction pressure on an older hose could cause it to collapse. I would also replace any hoses that have a hole.Reply
FloridaPoolBoy Posted: 5/1/2018
Quick question regarding a loss of pressure and vacuuming. I just unwrapped my pool from the winter, and Im working on getting it summer ready. I'm losing all my pressure when I go to vacuum the pool. This is a problem I have never had, and could use any advice. When I turn on the pump (sand filter, above ground pool) my PSI gauge shows 8psi which is normal for my pool when the filter is clean. I can let it run for hours with no loss of pressure. When I attach the vacuum hose to the intake I have an immediate and complete loss of pressure. I take the hose out of the intake (the only one this pool has), reprime the pump, and I'm back to 8psi. I've verified the hose was empty of air by submerging it in water and working all the air out. I even went so far as putting a hose with a clog buster on one end and pushing the air out under water just to be sure all the air is out. Again when I connect it I lose all pressure. I did find a small 1cm slice in the hose, but if that portion is submerged under water I can't image it would cause the lack of suction. Even if it were above the water line there is no way it's drawing enough air to cause the pump to drop to 0psi so suddenly. I also snaked the hose to make sure there was no blockage in the line. Maybe it's time for a new hose, but I don't see how that would change anything. Any thoughts at all on the next steps I should take? Thanks guys!Reply
INYOPools Posted: 4/24/2018
If your main concern is a sucking air leak, the quickest and easiest way to find it would be the "smoke trick." With the pump running, use a lit cigarette or incense stick for smoke, wave the smoke source close to the full length of exposed pipe including tees, valves, joints and pump housing. If there is a suction leak the smoke will be drawn in.Reply
Scott Posted: 4/24/2018
Hoping you can help with a pump suction issue; our in-ground pool includes a spa that is isolated during use with valves at the suction side of the pump. Unfortunately my wife closed ALL pump intake valves in error and our Pentair variable speed pump deadheaded for a whole day prior to discovery. Pump motor sounds like is still running fine, I replaced the mechanical seal and housing gaskets for good measure and everything seems to be working properly with impeller, etc. Now having problem with suction / cavitation; barely enough suction to make the vacuum move on its own and lots of air, trouble priming. I suspected a leak in the intake piping since piping got hot and even turned a little grey during the deadhead. To diagnose and confirm, I ran simple temporary PVC piping (same size) directly from pump intake to pool and bypassed the intake system, valves, etc. For some reason the pump can't even pull water directly from pool into the pump, even though motor sounds fine and impeller, volute, etc seems to run properly. Any ideas on what I should look at next or what my problem might be?Reply
Inyopools Posted: 4/12/2018
Hello Arizona Mom - If none of the steps in this guide worked, check out Part 1 of the blog titled "Why are My Pool Jets Not Working". Another issue could be the plumbing. Check out the blog titled "How to Fix Priming Problems in Your Pool Plumbing".Reply
Arizona Mom Posted: 4/11/2018
Have been working with Hayward and their Preferred warranty company. My pool pump was working fine and everything worked up until I received a drive Error on my Ecostar. They repaired this under warranty. Now there is a problem with basket priming and the Suction side jandy does not even move in the pool. They have been her twice to try to fix. I am at my wits end. What could be the problem?Reply
Inyopools Posted: 3/22/2018
Hello KoalaTea Jarred - The most common culprits of an air leak are pump lid o-rings, plumbing fittings, valves, and drain plugs. Pump lid O-rings are a habitual offender of air leaks. The O-ring can expand or deteriorate over time and allow air to enter the pump. You can try applying a silicone or Teflon lubricant to see if it helps, but often times it needs to be replaced. Plumbing fittings will also draw air. A popular technician trick is to use burning incense. While the pump is running, wave the burning incense near suspected areas. The smoke will be drawn in, if there is a leak. Check the fitting on the pump intake, the couplings and elbows. Cut out and replace any fittings that have an air leak. Valves can be inspected like the plumbing fittings. Diverter valves will usually have internal O-rings. These O-rings can easily be replaced to fix an air leak. Simple ball valves are not usually repairable and need to be replaced, if there is a leak. Drain plugs are found on most pumps. These plugs are usually used to drain the pump when a pool is winterized. They should be tightened firmly into the pump. Inspect the drain plug and drain plug O-ring. Replace them if they look decrepit. As far as bleeding the filter prior to the pump stopping, you can do this but hopefully the issue will be resolved from one of the culprits above.Reply
KoalaTea Jarred Posted: 3/10/2018
Hello InyoPools, Quick query. I have a brand new SQ1202 motor, (replaced for Sta-Rite Max E-Glas II motor) and 2 months ago I rebuilt the wet end (new: impeller & screw, diffuser, basket, and all new gokit). I've cleaned all baskets, and no clogs or flow issues. I also have a Sta-Rite - Sys 3 Mod DE Filter - S7MD72. I've cleaned the filter meticulously and all gaskets are great! I'm 99% sure my top-mounted pressure gauge is broken, as the needle is stuck, and with a brand new pump, I'd expect to see some movement. Furthermore, the pump is moving water wonderfully smooth. I have no discernable spitting leaks, and the "crawler" moves great. I think I'm fine there. The issue I'm experiencing is a constant buildup of air in the filter, followed by very tiny air bubbles out of the return jets. I'm having trouble locating the suction side leak. Does any guru have a tip or two they'd share? Please and thank you! ...and also, is it possible to bleed off the back pressure just prior to stopping the pump, in order to avoid the inevitable backflow from the filter? Thank you, JarredReply
Inyopools Posted: 3/7/2018
Victor - It does sound like you have a clogged filter. It may look clean but sometimes oils and chemicals build up in the pleats of the filter which are hard to remove. Before buying a new filter, try cleaning the old one chemically. See our guide on "How To Chemically Clean a Pool Cartridge Filter".Reply
Victor Posted: 3/3/2018
C900 filter system- I have low pressure in return jets and small bubbles. I ran the pump with no filter and worked great with no issues. Once I re-installed the cartridge the low pressure and bubbles returned. Does this mean the filter needs to be replaced? Thank you!Reply
Victor Posted: 3/3/2018
Low pressure and Bubbles in return jets to the pool and strainer basket chamber does not fill all the way. I have a Hayward c900 and when I removed the filter cartridge everything worked fine with great pressure coming out of jets. Once I re-installed the filter cartridge the low pressure and bubbles returned. Does this mean it is the filter cartridge that needs to be replaced?Reply
Carmen Posted: 1/16/2018
My pool pressure was very low at 8 psi. I Googled it and went to your website. I read several times it could be the impeller is clogged. I followed your instructions to check and clean the impeller, and sure enough a few big leaves were stuck in it. The psi immediately went to 15 psi. It was so so simple and quick to check and clean. Thank you so much!Reply
Inyopools Posted: 11/13/2017
Confused - "No flow" means something is partially blocking the water flow in your system. Make sure your filter is clean, check the skimmer and strainer baskets, and check that the impeller in the motor is not clogged (a common problem).Reply
Confused Posted: 11/12/2017
my pool has a reading of "ps low or no flow". What does this mean and does it affect the temperature of the pool?Reply
Inyopools Posted: 10/24/2017
Love my pool ! - 1) When you replace motors you have to look at the motor Total HP (THP) rating which is the product of the HP and the Service Factor (SF) printed on the motor label. The THP of your new 1.0 HP motor may be equal to that of your old 1.5 motor. For example, if your old 1.5 HP motor had a HP of 1.5 and a SF of 0, it had a THP of 1.5. If your new motor has a HP of 1.0 and a SF of 1.5, it has an equivalent THP of 1.5. If they both have a SF of 1.0, the 1.0 HP motor is smaller than the 1.5 HP motor. 1+) Assuming your new motor has a THP reading of 1.0 and is smaller, you may have to reduce the impeller size as you suggest, but not always. See the parts list for your motor. Sometimes two adjacent motor sizes (1 and 1.5 HP) use the same propeller. 2) The smaller motor probably would not cause the pressure gauge to read 10 points higher. Try cleaning your filter or replacing the gauge.3) A smaller pump would reduce water flow which could reduce cleaner performance.Reply
Love my pool ! Posted: 10/22/2017
3 questions please ! My pool's 1.5 HP motor, quit / died. A pool service guy removed it, took to motor guy who had rebuilt it 6 years ago. No longer repairable, so he replaced it with a new motor. BUT not a 1.5 HP... new motor is 1 HP ??? Q #1 Should I insist he replace it with 1.5 HP as originally built ? My research shows going from 1.5 to 1 HP and not updating the impeller & diffuser to match the slower speed, will burn up the motor. (pool guy did NOT update impeller) Q#2 Could this be the cause of the Pressure Gauge going from 10 to staying at 20 ? Q#3 Is this why my Polaris barely moves around the pool often stands still ? (the wheels turn) The new Polaris is only 1 or 2 years old. Replaced it same time we bought new salt cell. Thank you!Reply
InyoPools Product Specialist Dennis R. Posted: 9/17/2017
TC - Check to see if your pump's impeller is clogged. That is a common problem. If you have a cartridge filter, try pulling out the cartridge and seeing if you have good pressure without the cartridge. If so, clean the cartridge or buy a new one. If you have a sand filter and haven't replaced the sand in 5 years, consider replacing the sand. Also, try blowing out the suction pipe from the pump's end using a Drain King attached to a garden hose.Reply
TC Posted: 9/14/2017
We have an inground pool with a side skimmer and a skimmer in the bottom of the pool. These are all plumbed back to a pump room with the filter and pump. We have lost all pressure at the filter and the water seems to "surge" when it comes in to the pump. The pool has turned very cloudy. I believe we have something wrong on the suction side or maybe debris plugging one of the lines from the skimmer? Any suggestions?Reply
InyoPools Product Specialist Dennis R. Posted: 8/14/2017
bhturnow - It sounds like you may be getting back pressure building up in the top of your tank due to a suction air leak. If you open up the relief valve on top of the filter when the pump is running, is air released and does your pool pressure go back up. Or when you turn off the pump, do you have a water surge back to the skimmer? These are symptoms of back pressure build up due to a suction leak. See Step 7 of this guide. To locate the suction air leak, try blowing smoke around each of the suction side connection and the pump cover. If you see smoke getting sucked into the system, you’ve found your leak. People have also brushed a soapy solution around the connectors to see if little bubbles are sucked into the system.Reply
bhturnow Posted: 8/11/2017
Hello.RE: Hayward DE Filter and Hayward MaxoFlo 1.5HP pump
Any ideas on why my filter starts off great with pressure but then after 30-45 minutes the pressure lowers. It goes from about 13psi to about 22psi and you can feel the lower pressure. I have completely disassembled both the pump and filter and still no luck. I soaked the DE filter for 13 hours and cleaned it well. There are no clogs anywhere. I am lost. The pump sounds great and I even changed the impeller seal to be safe. The pump is not overheating. Thank you for any tips. Be well. Brad
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InyoPools Product Specialist Dennis R. Posted: 8/7/2017
TjaX - It sounds like you have an air leak on the suction side of the pump. A leak on the outflow side would not create air in your filter. They'd squirt water out. To find your suction air leak, try blowing smoke around each of the suction line connections. You would see some of the smoke being sucked into the leak. If you haven't replaced the O-ring under your pump's strainer cover for a while, I would suggest doing that.Reply
InyoPools Product Specialist Dennis R. Posted: 8/5/2017
Anonymous (local store) - Unfortunately, we do not have a pool company near Indian Falls, Maine.Reply
TjaX Posted: 8/4/2017
Whether valve is set to Skimmer or Floor Drains, water rushes into pump, but threw the clear cover to the pump the water doesn't fill the chamber completely and there is air in the pumps filter basket. Appears to be pulling in water, but I can't seem to get any pressure in my filter. I have primed and it seems like its flowing, but after purging the air from the top of the filter and closing it, it still doesn't build pressure, and I have to let the air out again. It seems like I have a air leak on the outflow side? No visible pressure on filter (gauge is good), flow only comes out of 1 out of 3 return jets, but there is flow.Reply
Anonymous Posted: 8/2/2017
Do you have any pool companies near island falls maine ...helpReply
InyoPools Product Specialist Dennis R. Posted: 7/20/2017
Kim - If you upgraded your pump to a larger size, your filter may not be larger enough to handle the water flow. Check the GPM rating on your filter to make sure it is at least as high as the pump GPM rating.Reply
InyoPools Product Specialist Dennis R. Posted: 7/19/2017
Kish - Try backing off to 80% DE that you add after a backwash, and if your filter has a breather tube down the center of the tank, make sure that tube is not clogged.Reply
Kim Posted: 7/17/2017
My pool pump is new an recently attached to a 16 by 42 intex pool . Its pushing water out fast but the suction in the pool is weak an not sucking in dirt an not keeping my pool clean . My finger dont even stick cause the suction is so weak is this normalReply
Kish Posted: 7/17/2017
I have a Hayward EC40 Perflex DE filter with a 3/4 HP motor for my in-ground pool. The filter's fingers were pretty dirty, so I had them acid washed and clean. This has improved the water pressure, however, it only runs for about 5 minutes before the pressure increase from about 10 psi to over 40 psi and the circulation stops. After bumping the filter and/or back-washing, the same symptoms re-occur. Help!!!Reply
InyoPools Product Specialist Dennis R. Posted: 7/13/2017
Autumn - If I understand you correctly, air got into your skimmer while you were cleaning it out, causing your pump to lose prime and water flow stopped. You just need to reprime your motor. See our guide on "How To Prime a Pool Pump".Reply
Autumn Posted: 7/12/2017
My her stopped blowing as I was cleaning out the skimmer basket. At some point I did stop water flow from going into the skimmer, how do i fix it so the jet comes back on?Reply
Sonal Posted: 7/3/2017
Your advice is spot on. I went step by step, simplest solution to the most complex and within a week, got my pool from a swamp that had poor pressure to clear with normal pressure. Your advice and tips have definitely saved me hundreds if not a thousand or so. I rebuilt a couple valves and learned tons in the process. Thank you for the help and allowing me to have the pool back for the summer!Reply
InyoPools Product Specialist Dennis R. Posted: 6/30/2017
KatieRI - Sounds like you have a suction leak at or before the pump that is letting air in the tank and causing a gradual buildup of backpressure. See our guide on "How to Identify and Correct Air Leaks". Many filters have a breather tube down the center of filter tank to relieve this air pressure. Make sure that tube is clear. The glug glug noise is common. Also, it is normal to see large bubbles at the returns when the pump is first starting up and purging air from the system pipes.Reply
KatieRI Posted: 6/28/2017
We were having an issue with low pressure and the flow of water filling the pump basket was too weak. (DE filter) I thankfully came across your advice to clean the impeller- full of debris. Also backwashed. Seemed to fix the problem! Except it was only temporary...Now the vacuum suction seems weak. When the pump is on recirculate the flow of water into the pump basket is forceful and water splashes against the cover. If we quickly turn to filter, this flow lasts for a while, but then the flow seems to lessen and water no longer splashes against the cover- there is just a constant flow of water. Same happens when vacuuming. If the pump is turned off for a few minutes and we try to start on filter, the flow never gets going well enough to create good pressure. Why would it work well on recirculate but not on filter?
A couple of other things that might be worth mentioning: 1.) When I removed the pump basket cover to clean out the basket, I hear a "glug, glug, glug" as the water level goes down. (Not sure if that's normal or if it should flow smoothly.) 2.) There are also bubbles that come out of the jets, and this has been that way for years and things have always worked fine. When the pump first starts there are big bubbles, then tiny bubbles once the air clears. 3.) We open the air relief valve when the filter starts until we get the stream of water, then we close it. It doesn't seem to take long (5-10 min) before there is more air to be released. (Also not sure if this is normal?) Thank you for your helpful advice!
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