Intermittent Water Pump Cycling When No Water is Running, Diagnose & Cure
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How to diagnose, find and fix the cause of intermittent or irregular well pump cycling on and off: This article explains how to diagnose & repair water pump intermittent cycling - the water pump comes on when no water is being run in the building.
Intermittent water pump cycling means that the water pump comes on for no apparent reason.
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What is Intermittent Water Pump Cycling, What Causes It, and How is it Corrected?
Intermittent water pump cycling which we explain here means that the water pump comes on for no apparent reason - that is, you are
unaware of any water running in the building. (When water is running in a building served by a private well and water tank and pump
system it is normal for the water pump to cycle on and off to deliver water to the building.)
So here we are
not talking about "short cycling" (see
SHORT CYCLING WATER PUMPS) in which the water pump turns on and off too frequently when water
is being run in the building. However, some of the
causes of "short cycling" might also lie behind "intermittent pump cycling".
Here are the more likely causes of the water pump coming on at odd times when you're not (aware of) running any water. You may want to investigate
these possible causes roughly in the order they are listed below.
- Running Toilets: A toilet somewhere in the building is running - this can be VERY hard to spot - unless you are meticulous. I've tried wiping the toilet bowl interior to make it dry and then feeling it later for wetness above the water line, or watching the water in the toilet bowl for ripples, or placing a little septic dye or food coloring in the toilet tank to see if it appears in the bowl below, or, simplest, simply turning off all toilets at their supply valve to see if the pump cycling goes away. A leaky flush valve or a leaky fill valve in a toilet causes this problem. See Toilet Runs Continuously for diagnosis & repair of running toilets.
- Leaky Plumbing Fixtures: A plumbing fixture such as a sink, tub, shower, or clothes washer is leaking slowly - such as a faucet or shower head dripping into the fixture (where you can see it) or worse, dripping into a hidden building cavity such as a wall or ceiling cavity (where water stains eventually show up below) or into a floor or crawl space (where you may not see the leak). See LEAK TYPES, Water Supply/Drain Pipe
- Leaking Water Tanks: An air leak at the water pressure tank, above the water line in the tank, (or a water leak from the water pressure tank) can cause the tank to slowly lose air and the water pump to cycle on. This is possible with both traditional steel water tanks and with modern captive-air bladder type tanks (water is in a separate bladder inside the tank). Older water tanks which have an air volume control (which rarely work) are designed to automagically add air to the water tank as needed, so if the AVC is working and if there is a little air leak on the tank somewhere (often you can spot a rusty pinhole leak), this condition could continue for a while before being diagnosed. We discuss leaks in water tanks and temporary repairs at WATER TANK REPAIR PROCEDURES
- Leaky check valve or foot valve: A check valve at the pump or a foot valve in the well at the bottom of the water pipe could be failing and leaking, sending water backwards from the pressure tank, through the water pump, and back into the well. This can eventually lead to loss of pump prime and loss of all water supply as is discussed at our website. See CHECK VALVES, WATER SUPPLY and see FOOT VALVES, WELL PIPING for diagnosis & repair procedures.
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Leaks in well piping: A water leak in the well piping between the building and the well or even inside the well could also cause a back-flow of water from building to well and lead to pump cycling on and off.
Leaks in well piping can occur at connectors such as those used on plastic water piping, or well piping leaks may be due to corrosion and perforation of older galvanized steel well piping - shown in our photo at left. See WELL PIPING LEAK DIAGNOSIS for details.
Jeremy Rasmussen (Rasmussen Well Drilling, Inc.) points out that galvanized steel well piping is particularly prone to corrosion and leak perforation in the section of well piping that is repeatedly wet then exposed to air during the normal draw down cycle of water inside the well casing at each pump cycle.
The galvanized iron well piping shown was on a 180 foot deep well in Two Harbors MN. We elected to leave the corroded piping in place until leaks or pump problems justified its replacement.
Because of the trouble and cost of pulling deep well piping, Rasmussen recommends that when pipe replacement is needed, the well pump, air vent (if present) and other in-well equipment should all be replaced at the same time.
- Defective Pressure Control Switch: A defective pump pressure control might, in theory cause this intermittent cycling but in more than 30 years of practice I've not found this to occur.
Contrasting Intermittent Well Pump Cycling with a Short-Cycling Water Pump Problem or with Lost Water Pressure
Short cycling of a water pump means that the water pump turns on and off too rapidly or too frequently when water is being run in the building. If this is the problem with your water pump, see SHORT CYCLING CAUSES. See What Causes "Water Pump Short Cycling" and Water Tank Repairs: Diagnose "Water Pump Short Cycling".
Intermittent water pump cycling which is discussed at Intermittent Water Pump Cycling When No Water is Running means that the water pump comes on for no apparent reason.
Loss of water pressure means that the pressure with which water enters a plumbing fixture has become too slow, or is sometimes too slow or weak in water flow rate, or water flow may stop entirely. See WATER PRESSURE LOSS DIAGNOSIS & REPAIR
How To Fix Water Pump Intermittent Cycling
Review the list of intermittent well pump cycling provided just above and fix that cause
To correct the problem of water pumps coming on when there is no apparent reason, we need to find which of the causes listed
above is occurring. Look for problems like those listed earlier in this article and fix them.
Look for other hidden causes of well pump cycling
IF that does not cure mysterious well pump cycling when you believe no one is running water in the building, look for more hidden causes such as a hidden leak in water supply piping or well piping underground.
The most common causes of hidden causes of intermittent pump cycling:
- water is running somewhere in the building without notice, such as a running toilet
- a leaky check valve or foot valve at the water pump or in the well
- a leak in well piping somewhere between the bottom of the well and the pressure tank in the building
Multiple faults or causes of well pump cycling on and off?
Remember that though it's not common, on occasion more than one water pump cycling fault could be present. Each of the possible causes listed above
is also discussed as a diagnosis and repair topic at this website.
Frequently Asked Questions (FAQs) about intermittent cycling of well water pumps - pump runs for "no reason"
Question: Intermittent running of our well tank, tank replaced, bad foot valve?
I have a similar issue. First we experienced intermittent running of our well tank. The tank would run when we were not calling for water.
We had the tank replaced and upgraded from 20 gallons to 35 gallons. Our pressure switch is set at 30/50 psi. We were told that the valve(??) was bad because water did not shoot out and air was sucked back in when the tank was replaced. Since having the tank replaced, the psi still decreases when we're not running water. In addition a new problem has started.
Our water slows down and then stops completely for about 15 seconds during various times of the day (showers, washing dishes, etc.) and the water will spit at times (running faucets or when the toilet fills up). We verified that we have no leaks in or around the house. Our pump is submersible. Thank you very much. - Tara
Sorry, I have to make a correction. Our pressure switch is set at 40/60 psi. Thanks.
Reply: a bad foot valve can cause intermittent well pump and tank running and loss of well prime
Tara:
I'm not sure what "valve" you were told was bad. Perhaps a foot valve or check valve? A bad check valve or foot valve can lead to loss of pump prime and thus loss of water pressure. While that cause and symptom are not usually intermittent but rather a hard failure, a slow leak in a check valve or foot valve could show on occasion up as intermittent water pressure loss. That is, if water is being run frequently and the leaky valve is a slow leak, the pump may retain enough water to not lose prime (assuming we're talking about an above-ground well pump here). But when water is left off for a longer period and the slow leak has time to lose more water from the pump, piping, and even pressure tank, one could lose water pressure.
The fact that you replaced the water tank and are not running water but still see a loss of water pressure read on the gauge at the tank is a strong suggestion that you have either
- a leaky check valve or foot valve
- a leak in well piping somewhere between the bottom of the well and the pressure tank in the building. WELL PIPING LEAK DIAGNOSIS
When your well pump is submersible (yours), you won't experience loss of prime (the pump is under water and always can prime itself). But you can see air in the well piping and water tank system and loss of water pressure as we've both described.
The "spitting" you describe at faucets or at a toilet can be caused by air entering the well piping through the same leak that in other pressure conditions lets water leak out.
I think it's time to have a plumber or well expert investigate the well piping for leaks.
Follow-up from Tara: I am struggling to understand why our water stops and spits now after having the tank and valve replaced
Thank you for your reply. Our invoice states that the "check valve" was replaced. I do know that it is the valve that is very close to the well tank. Are the terms "check valve" and "foot valve" interchangeable for the same valve or are they two separate valves? As I am understanding it, I think the check valve is visible and near the tank; the foot valve is below the ground at the bottom of the submersible pump.
I am struggling to understand why our water stops and spits now after having the tank and valve replaced when we did not have this problem prior to the new tank and valve. Just tonight I have noticed a hissing sound coming from the well tank that I did not previously hear. Our plumber is on vacation this week. I am trying to educate myself as much as possible before next week. I'm concerned about assuming the problem is the foot valve and pulling up the pump as our plumber seems to want to do. I would think that if the the foot valve was leaking we would have had the loss of water all along. Thank you very much.
Comment:
Tara a check valve may be at an above ground pump or at the bottom of the well (where it's better called a foot valve.) If the worker did not pull the well piping they didn't replace a foot valve. See WELL PIPING CHECK VALVES and the separate article WELL PIPING FOOT VALVES for details.
I don't know what's hissing (air, water, or a control or an air volume control). I hope you'll tell us what the plumber says about that hissing - it's important in helping other readers.
About your earlier comment and my reply: if you are not running water but still see a loss of water pressure read on the gauge at the tank is a strong suggestion that you have one of the problems we list above - or see How To Fix Water Pump Intermittent Cycling in this article.
Also, we have often seen that any work on a well, pump, piping, tank and water tank system can disclose other marginal components or problems that were not obvious earlier. For example just stirring up dirt and debris in the well or well piping can cause clogging of the water pressure sensor switch leading to odd water pressure behavior, or clogging of a water filter leading to loss of pressure. And both old water types on occasion a new bladder-type water pressure tank can suffer from a bladder that sticks to itself, preventing water from entering or leaving the pressure tank. See WATER PRESSURE TANKS, BLADDER TYPE.
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Technical Reviewers & References
Use links just below or at the left of each page to navigate this document or to view other topics at this website. Green links show where you are in our document or website.
INTERMITTENT CYCLING WATER PUMPS - see detailed links at page top & left
- Rasmussen Well Drilling, Inc., 1793 Hwy 61, Two Harbors MN. Jeremy Rasmussen provides third generation well drilling and plumbing services on the North Shore of Lake Superior. Photos by DJF. Tel 218-834-3387. Email: rasmussenwell@frontier.com
Quoting:
We serve the north Shore – Lake, Cook, St. Louis, Carlton and Pine counties, including Duluth, Grand Marais, Clouqet, Carlton, Finland, Isabella, Silver Bay, Grand Portage, Saginaw, and everywhere in Northeastern Minnesota.
- Smart Tank, Installation Instructions [ copy on file as /water/Smart_Tank_Flexcon.pdf ] - , Flexcon Industries, 300 Pond St., Randolph MA 02368, www.flexconind.com, Tel: 800-527-0030 - web search 07/24/2010, original source: http://www.flexconind.com/pdf/st_install.pdf
- Typical Shallow Well One Line Jet Pump Installation [ copy on file as /water/Jet_Pump_Grove_Elect_Jet_Pumps_1.pdf ] - , Grove Electric, G&G Electric & Plumbing, 1900 NE 78th St., Suite 101, Vancouver WA 98665 www.grovelectric.com - web search -7/15/2010 original source: http://www.groverelectric.com/howto/38_Typical%20Jet%20Pump%20Installation.pdf
- Typical Deep Well Two Line Jet Pump Installation [ copy on file as /water/Jet_Pump_Grove_Elect.pdf ] - , Grove Electric, G&G Electric & Plumbing, 1900 NE 78th St., Suite 101, Vancouver WA 98665 www.grovelectric.com - web search -7/15/2010 original source: http://www.groverelectric.com/howto/38_Typical%20Jet%20Pump%20Installation.pdf
- Water Fact Sheet #3, Using Low-Yielding Wells [ copy on file as /water/Low_Yield_Wells_Penn_State.pdf ] - , Penn State College of Agricultural Sciences, Cooperative Extension, School of Forest Resources, web search 07/24/2010, original source: http://pubs.cas.psu.edu/FreePubs/pdfs/XH0002.pdf
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