Foot valve on well piping (C) Daniel Friedman Foot Valves on Well Piping: Explanation & Repairs
Water well foot valve troubleshooting
     

  • FOOT VALVES, WELL PIPING - CONTENTS: Definition of a foot valve; how does a well piping foot valve work, and why do we need a foot valve on well pipes?Foot valve failures and loss of well pump prime - diagnosis & repair. Foot valve failures and loss of water pressure or water flow - diagnosis. Check valves on well piping: what's the difference between a foot valve and a check valve? Where do we find the foot valve (if any) and why are foot valves used on pump and well systems? Is it a good idea to use more than both a check valve on a pump and a foot valve on the well piping? Causes of well & pump foot valve failure; How to diagnose a bad or leaky well piping foot valve - a cause of lost well pump prime
  • POST a QUESTION or READ FAQs about locating, using, diagnosing, repairing, or replacing well pump check valves and foot valves.
  • REFERENCES

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Well Foot Valves:

This article describes the foot valve used on well piping for water well Pumps & Water Wells: we explain what a foot valve is, how they work, why they are used, and how to diagnose troubles with this special in-well check valve found at the bottom of well piping in some wells.

We provide advice about loss of well pump prime due to bad foot valves and what to do when things go wrong with the check valve.

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What is a Foot Valve and Why do we need one on well piping?

An Explanation of Well Piping Foot Valves

Schematic of a shallow well single line jet pump water system (C) Carson Dunlop Associates

Carson Dunlop's sketch (left) shows the main parts of a one-line jet pump well installation. Nearly all well pumping systems, one line jet pump, two line jet pump, or submersible well pump, require a foot valve installed at the bottom of the well piping.

A Well Piping Foot Valve is a one way or anti-siphon valve which is installed on the pick-up end of the water pipe near the bottom of the well.

The foot valve prevents water from flowing backwards out of the jet pump and well piping back into the well when the jet pump stops operating. You can see Carson Dunlop's sketch of a foot valve here.

Foot valves are also used on deep well installations to help protect against loss of prime in the well piping system.

Since you won't normally see the foot valve on well piping (it's down in the well) we have included a photograph of a well piping foot valve at the top of This article .

Watch out: without a working foot valve, a shallow well jet pump is likely to lose prime and will stop working properly, risking loss of water supply to the building and even damage to the pump itself.

Foot valve check valve portion (C) Daniel FriedmanOur photo (left) shows the outlet end of a well piping foot valve.

As you may guess, a foot valve is basically a check valve combined with an inlet strainer (visible in our page top photograph). The strainer prevents picking up large debris that could clog or jam the foot valve in its open position (or that might damage the water pump itself).

The check valve is a one-way valve that lets water flow up from the well and into the well piping. The spring loaded check valve closes when the well pump stops pumping.

Closing the check valve prevents water in the well piping from falling backwards into the well when the pump has stopped running. We need this function to keep the well piping and water pump filled with water - otherwise the well pump may lose prime, leading to loss of water in the building.

If the well piping foot valve is leaky and water runs back into the well we increase the wear on the water pump as it has to run more often, and pretty soon the water pump will lose its prime (water inside the pump mechanism) and it may be unable to retrieve any more water from the well whatsoever.

When a shallow well appears to have "run dry" one of the first things to check is whether or not the foot valve needs to be replaced.

Foot Valve Clearance from Bottom shows that the well piping and foot valve are inserted into the well some distance from the very bottom of the well (inches to a few feet). We need this clearance to reduce the tendency of the well pump to pick up mud and debris from the bottom of the well.

Reader Question: do jet pumps come with a built in check valve or do I need a foot valve or both?

I have model pkg 1-54AP 2" single pipe jet kit for a sta-rite sld-l 3/4hp jet pump. Does the jet package come with a built-in check valve and if it does, do I need a foot valve? Thanks! - David

Reply:

David take a look at the page top photo - if your kit didn't include something that looks like that, you don't yet have a foot valve.

The foot valve is placed at the bottom of the intake water line in the well; since your jet pump is above ground, it's a physically separate component.

Yes some jet pumps include a built-in check valve.

It's true that some jet pumps include a check valve in the nose of the pump; and it's also true that some experts recommend only using a single check valve. If your well is quite shallow, say less than 27 ft. you might get away without a foot valve. But if I were installing new equipment including piping into the well, I'd put in a foot valve - as the most reliable component, and because it's easy to do now and more trouble to add later.

Also see our discussion of the WELL PIPING TAIL PIECE that protects well pumps from damage in a low-flow poor recovery rate well.

Other things to check when losing well prime

If you are having trouble losing well prime and suspect a bad foot valve or check valve, also see

CHECK VALVES, WATER SUPPLY about above-ground check valves in the water system

PUMP PRIME, REPEATED LOSS of

WELL PIPING LEAK DIAGNOSIS

WELL PUMP PRIMING PROCEDURE

Other causes of loss of well pump prime are at WATER PUMP DIAGNOSTIC TABLE. Also take a look at   WELL PUMP PRIMING PROCEDURE

Foot Valve Installation

Reader Question: 10 Feb 2015 question: foot valve for deep well? said:
I have a new 200 foot deep 4" diameter well; is it possibly to use a foot valve and pvc piping instead of a submersible pump? Any rish of the foot valve damaging the pvc? Will a foot valve work at 200 foot depth? Thanks.

Reply:

In reverse order,

A foot valve doesn't damage the piping to which it's attached.

A foot valve will work at 200 ft if properly installed. Here is an excerpt from Flomatic's foot valve installation instructions

" In general Flomatic valves are pressure rated 400 psi or 920 feet
of water pressure. This does not mean that a valve can be set at a well depth of 920 feet. To alleviate and reduce
the hydraulic shocks in the riser pipe it is recommended that a check valve be installed every 200 feet in the riser
pipe. "

  • "Foot Valves Installation Instructions", Flomatic Corporation, 15 Pruyn's Island, Glens Falls NY 12801, Website: flomatic.com, - retrieved 2/10/14, original source: www.flomatic.com/assets/pdf_files/oem/16048.pdf

Foot Valve Troubleshooting

Pump runs but is not pulling any water

(Apr 9, 2014) ashok said:

I have 2 water lines connected to an above ground water pump which is attached to a tank. last winter i could not get water and i checked the pump and found it had a crack at the impeller housing. I got a used pump and attached the lines to it. The pump works fine but is not pulling any water.

Also there is no place to pour water to prime the pump so i installed a T with a shut off nut. I did pour plenty of water in this T at times i get some pressure , maybe for a second and then nothing. I am wondering if i may have switched the pipes supply to discharge or vice versa. please advice

Reply:

Ashok, you might have switched lines, or the same freezing that cracked the pump may have cracked a well line leading to leaks or loss of prime. Check out our alternative methods for how to prime the well pump by starting at

WELL PUMP PRIMING PROCEDURE

Pump used to

Possible well piping leaks vs foot valve malfunction

(Apr 3, 2014) keith watkins said:

I installed a new deep well pump,which came with a new pressure switch,a new pressure tank & a new foot valve.The switch is a 20/40 and I dropped 2psi on the tank which made it at 18psi,and this was 18psi BEFORE I installed the tank.My water looses its prime,but by only a glass of water or so.It quits flowing water after a couple minutes,and then I have to prime again.

The foot valve is off the bottom.The foot valve is below water level.My well is about 25ft deep until it comes to water level and the the foot valve is below water about 15ft.The only thing that is not new is the long pipes going down the well.Can you help?

Reply:

Keith,

Given all the new stuff this sounds to me as if there is a leak somewhere or the foot valve is sticking or leaking a bit before it closes.

Foot valve to pick-up for lake water

(Mar 30, 2014) William said:

I have a shallow well jet pump 1.5 hp with a sealed supply line to a lake. It was cycling too frequently and going on and off every few seconds with poor flow to house. I have replaced the pressure control unit (set to kick in at 30 psi and out at 52 psi, and does) and replaced the filters between the pump and the storage pressure tank (80 liters/pressure is fine in the tank at 28 psi empty) with success in that the cycling is gone.

But, when I run water (hot or cold), the system only gives about 3-4 gallons of water (rated to give 7-8 gallons at least) and, after the pump kicks in at 30 psi (appropriately), the pump just does not seem to be able to keep up the water flow.

The flow in all house taps slows by half and the pump keeps running until the tap is turned off. It then takes the pump twice or more as long as it should or 10-15 minutes to fill the pressure tank again, (the motor gets hot, though it shuts off appropriately at 52 psi). I suspect I have a problem with the pump. such as needing to replace the impeller. But, would like some advice before I get a new impeller, seals, etc. and take the pump apart. Thanks for your advice!!

I should add, I am in an isolated location 2 hours+ from any plumber or city. The pump is 10 years old.
If I do replace the pump parts, such as the impeller, I wonder if I should install a filter of some kind (though I can't find one recommended for this purpose) between the pump and the lake supply line (before or after the check valve?) to prevent sediment, etc. from fouling the pump again.

Reply:

William, usually the foot valve installed at the end of a lake pick-up is the screen against picking up debris into the pump system; ou'll want to investigate where the pick-up is in the lake and whether it's sitting in muck or algae or weeds.

Follow-up:

Thanks, DanJoe.
Presently, the foot valve is under 4 ft of ice, usually suspended 2 ft from the bottom in 10 ft of water (or 14 ft, if you count the ice). I will assess it after spring break-up in 6-8 weeks. (I am in northern Canada.) I did not check it last year, but the year before, it did have some build-up of crud and algae, so I made sure it was repositioned up off the bottom held by a cement block. There are no weeds and the bottom is generally open sand mixed with a bit of mud.

Do you mean that the lack of water flow could be just the pump is unable to draw water due to foot valve blockage, even with such a strong motor? If so, I will postpone taking the pump apart until I can check and clean the foot valve. (It does have a coarse mesh cover.)

Reply:

Yes William, on occasion we have to scrape the crud off of the foot valve and check that it's up a bit off the bottom - I've done the same thing with a friend who had this system at Lake George in NY. He also invented and we installed a typical over-engineered system that pumped air back down the water line in winter so that he could turn water on and off into his home during times when the lake was freezing.

Question: Water pressure loss after electrical power outage - lightning strike & lost well water

Hi,after a power outage that lasted the entire day, I now have no water at all. I'm new to all of this, so please bear with me. Although, thanks to your very informative site I'm learning. I have a single line jet pump and am not sure what the depth of the well is.

I tried to re prime with no success, so had a well person check it out. He spent over an hour adding water, turning the pump on and off, gradually bringing the water and pressure back up to the top. Right as he was ready to give up it worked, and water was flowing strong out of the faucet. It didn't last long though, and he said there must be a crack or hole in the piping of the well, which is letting air in.

What I don't understand is I had water before the power outage with a supposed cracked or damaged pipe. So since he got the water back up to the top and flowing, why wouldn't it continue and keep the prime since it was before?

He advised that since the well is older (25 years) and the cost to find out what is wrong with it would be $1500 plus the cost of repair, that I would be better off having a new well dug, which is $3800.

I looked into claiming it on my insurance, but was told it had to be caused from a lightning strike, not just a power outage. Is it a possibility that whatever is wrong could have been caused by lightning, and if so, how could it be confirmed? - Valora

Reply: check for bad foot valve and replace it; refer to details of well pump priming procedure, check valves, foot valves

Indeed, Valora, a lightning hit can burn up electrical wiring, controls, pumps, and can even damage plumbing pipes. But your description sounds as if there was a loss of prime and difficulty re-priming the pump. If the water system has a bad foot valve (located on the bottom of well piping) and power stays off for some time, you are more likely to lose well prime. The proper repair is to pull the well piping and replace the foot valve.

The reason this problem shows up after a power loss is that even though the foot valve may have been leaking for some time, as long as you had electrical power, when the foot valve leaked the dropping pressure at the water tank caused the pump to turn on by itself, restoring water, pressure in the water tank, and prime before so much water was lost that the pump couldn't recover by itself. But when power was lost for hours, so much water drained back into the well that the well could not re-prime itself when it started again.

See WELL PUMP PRIMING PROCEDURE

 

Continue reading at WELL PIPING CHECK VALVES or select a topic from the More Reading links shown below.

Or see WELL PIPING LEAK DIAGNOSIS

Or see WATER PUMP INTERMITTENT CYCLING

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FOOT VALVES at InspectApedia.com - online encyclopedia of building & environmental inspection, testing, diagnosis, repair, & problem prevention advice.

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