No Backwash Or Rinse Pressure On A Pool Sand Filter...

I have an above ground 21' round pool.

While starting up the pool I have had problems with the Backwash and Rinse.

While running pump in Backwash or Rinse I have little to no water coming out of waste.

Change valve back to Filter and I have 10psi and good water flow. This does not make since to me.

Have any ideas or suggestions?

Thanks for the question

You probably have a top Multiport valve that turns to different settings.

Are your turning the pump off before you move the valve control?

If you have ever taken the top valve apart, the postion of the inside diverter may not have been replaced correctly.

You and/or a good pool tech might need to make sure the solid portion of the diverter lines up with the 'CLOSED" port on the valve. If this is lined up everything else should line up in the correct position.

Be sure the settings "click" into place. If they don't the O-ring or gasket might need to be replaced.

Everyone with a pool filter must turn the pump off before changing valve positions. If you don't it might blow the "spider" key stem gasket.

You should use the "RINSE" cycle. Why you're getting this could be one of two things:

1. The sand might be imbedded with debris and hasn't been backwashed enough to clear it out. You may need to change out the sand or degrease it.

2. If the Multiport valve checks out alright (if you replaced the key stem gasket) it may be the laterals in the filter tank. If the filter or laterals are old or if it wasn't closed down properly for Winter, you may have a cracked or broken lateral.

It's probably not the stand pipe between the laterals and Multiport valve, if applicable.

Hope this helps and have a great and safe swimming season.


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Jun 23, 2017
Backwash isn't working
by: Alana


Just got a new Hayward sand filter last year (had same type for 15 years with no issues) We set up this season like we have every season before but this year we are racking our brains. Pool is cloudy, not green, but very cloudy. The filter at first glance seems to be working fine but it is definitely not filtering as there are tiny particles floating even after running the filter for extended periods. The backwash setting didn't seem to be working either. Water would just lightly flow out and if you pick the hose up even a tiny bit it would cease. I took the entire filter apart starting with the MPV first because I thought it might be the gasket...but all was well. Next I took the sand out and cleaned the pipe and the laterals...they were filthy and some were clogged. I thought I had solved the problem. I put it all back together and it seemed to be working fine, backwash worked and I went to bed. In the morning though the same problem was there. I'm at a loss... help please!

Jun 22, 2015
Low Filter Pressure and No Backwash
by: Anonymous

So, this is totally embarrassing. Yes the stand pipe broke and laterals were clogged. My low filter pressure and no backwash WAS MY OWN fault. I failed to refer to my hook up diagram and had the hoses bt pump\filter\returm BACKWARDS!! Hooked them up correctly and all is well!

May 31, 2015
Still No Backwash Pressure
by: Amy B

This answer was so helpful! I checked the MPV and spider gasket - all OK, things lined up, etc. Next went to check the laterals. My problem was 2-fold. Standpipe cracked at bottom, and laterals completely clogged. Replaced standpipe with PVC (saving about $80!) and thoroughly cleaned laterals. Replaced everything, and now my filter is pressue is back up around 10-12 psi, but I still have no backwash or rinse pressure? FYI, MPV is new as of last season. Not sure if that matters.

Thanks for the question Amy

These are all of the troubleshooting tips I have, minus one. If the MPV and spider gasket are good and intact, and you've done everything else listed here, the last thing is a possible plug in the backwash line or chamber inside the MPV housing where the entire handle sits. Check for that and let me know how it works.


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Little To No psi

by Mike A

I have a sand filter. In years past we put 3 lbs. of sand in the filter. This year I did the same with new sand from my local pool store.

Started out the season with 12 psi now it went to 6 then 4 then 3 now 2. I bought a new pressure guage and this reads 0 psi. Checked hoses for clogs, backflushed filter nothing helped.

I see no leaks or drips of any sort......any ideas

Thanks for the question Mike

Here are some things you'll want to check:

Be sure the sand is at the rightt level. This is known as "freeboard". The top of the sand to the top of the filter. You can check with the filter manufacturer to see what the correct amount of sand your filter uses.

Baquacil and similar products can clog up your sand. Also, swimmers that use oils and lotions.

Be sure the impeller is not jammed up with debris. Turn off the breaker, then the pump motor, remove the pump lid and the basket. Stick your fingers in the impeller and remove any debris.

The pump basket and skimmers should be cleaned out and no blockage.

Back wash the filter.

You've checked the pressure gauge which is good. Many times pool owners will get a false postive on low or high pressure because of a faulty gauge.

Are there any bubbles coming out of the returns? If there is you may have a suction side leak.

Be sure the water level is between 1/3 - 1/2 up from the bottom of the skimmer. Water level below the skimmer and your system will draw in air.

Check out my first answer on this post:

How Do I Fix Low Skimmer Suction?

It has alot of good troubleshooting tips for low pressure.

Hope this helps and have a great Summer.


By: Mike
Date: August 4, 2011

It was the clogged impellar. Thank you so much for the advice.

I will recommend you to anyone I know.

By: Robert
Date: August 4, 2011

Good going Mike. Don't you wish most problems were just debris in the impeller of life?

Have a great rest of the Summer


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Jun 03, 2014
Sand In The Pool
by: Kim

I have a sand filter. We have just opened the pool over the past two weeks and the water is now clear and things seem to be operating normally.

There is however, what appears to be sand settling on the bottom. Any ideas what could be causing this?

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Pressure Won't Come Up On Sand Filter

by Robert Heit
(St. Albert, AB, Can.)

Have a new Jandy filter.

I put sand in it and started the pump. I had difficulty getting started.

When it did get going it surged with air bubbles and surged between 0 and 2 lbs.

I backed washed for 10 minutes. It started a little better, but then back to 0 to 2 lbs pressure.

I had put in the alternate sand.



Thanks for the question Robert

I'm really not sure what you mean by "alternate sand". If you mean crushed glass or organic matter that doubles as pool sand or filter media, then you can go to this post:

Sand Pool Filter..Changed The Sand With Something Like Sand

For low pressure, you can check out these similar answered questions:

PSI Gauge For Sand Filter Is Leaking And Not Working

My Pool Sand Filter Has Low Pressure..Low Psi & Multiport Valve Is Leaking..

You need to know if you put in the correct amount of sand and what the "freeboard" is. This is the measurement of the sand from the top of the sand to the top of the filter.

Change The Sand In Above Ground Pool Sand Filters

Sand Returning Back To Pool After Replacing With New Sand

Air bubbles obviously mean that air has entered the filtration system somehow. With new sand or a new system, you need to be sure some things are taken care of.

Be sure the O-ring/gasket on the pump lid is on securely and is clean without any tears or rips.

If the pump is having a difficult time drawing in water, you may need to prime it.

Get a bucket with pool water and fill the pump pot with water. Secure the lid and start the pump.

Be sure to release the air from the filter through the air release valve on top of the filter.

Keep the water level up in the pool between 1/3 - 1/2 up from the bottom of the skimmer.

This post is very good at troubleshooting low pressure:

How Do I Fix Low Skimmer Suction?

With new sand, just disregard the part about degreasing the sand.

An easy way to find out if you have a suction side problem are these two methods.

First, close the skimmer valve and open the drain valve. If you lose water pressure, your issue is in the skimmer.

Next, open the drain valve and close the skimmer. If there's water loss, the problem is the drain.

The above posts go into detail on what to do about those issues.

Hope this helps and have a fun and safe swimming season.


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Jun 26, 2018
Backwash fine, rinse has very little water to waste
by: Lynn

Jacuzzi 7 place multiport filter. Backwashed fine, rinse setting has very little water out to waste. Psi runs at 28-30. Water out of return jets seems normal.
New pump installed last year, sand filter is 15 yrs old.
Had TONS of pollen and also gray fungi mold on pool walls that I’ve been working to remove. Have run 1 qt of filter cleaning thru , no change. Backwashed many many times I do have a small air leak at union connection to the filter, could this be part of the problem? Don’t understand why it backwashes with plenary of water out of the waste line but almost none out of the rinse setting.

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Sand Filter Help Needed

by Les

I've had an above ground pool since 1984. This is the first time ever that I forgot to put in the strainer basket in the Jacuzzi pump when I was (Spring start up) vacuuming the winter debris.

I backwashed the filter, but I continued vacuuming the pool as it was backwashing.

Now I have only 3-5lbs. pressure indicated at the filter. Seems to me the filter sand is in sad shape. What is the easiest and fastest way to get this problem resolved?

I hope there is help for my stupidity!

Thanks for the question Les

Believe me you're not the first one who forgot to do something when working on a pool. I was changing an automatic timer on a customer's pool and forgot to turn the breaker off. I cut through the wire and got 220 reminders why I don't mess with electricity... even to this day.

The sand might not be in sad shape, you may have just lost too much sand during the excessive backwashing phase. Normally you will lose anywhere between 100 - 250 gallons of water when you backwash for 1 - 2 minutes. If it was 10 - 15 minutes, the loss will be significantly higher.

Turn the pump off and release the pressure with the air release valve. Remove the top and check the sand. If it's too low, you'll need to top it off.

This is called the "freeboard". It's the measurement from the top of the tank to the sand. You can call the sand filter manufacturer and get the correct measurements. Most people put in the correct lbs. of sand but fail to check the freeboard. When the sand gets wet it settles.

Here are some very similar posts to look over:

Little To No psi

Noisy Sand Filter And Sand Coming Out Waste Line On Backwash

Water Coming Out Backwash Hose? I Need Help

Look over the links above and check the sand.

If you need immediate assistance (within 24 hrs) or for emergency personal assistance, you can make a donation of your choice and I'll answer your questions by phone.

Contact Me


Hope this helps and have a great Summer.


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Jul 19, 2018
Help low pressure while backwashing
by: Anonymous

I have a hayward sand filter that I just replaced the whole standpipe and laterals. When I turn it on it seems to filter ok bur very low pressure during backwash and rinse. Also it seems to be putting a small amount of sand in the pool. I was thinking of replacing multi port valve but I wasn't sure if that will help. Any advice would be appreciated thanks Angie

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