Question? Just ask us!
Free Encyclopedia of Building & Environmental Inspection, Testing, Diagnosis, Repair
InspectAPedia ® Home
WATER PUMPS, TANKS, TESTS, WELLS, REPAIRS
WATER CONSERVATION MEASURES
WATER CONTAMINANT LEVELS
WATER FILTERS, HOME USE
WATER HAMMER NOISE DIAGNOSE & CURE
WATER ODORS, CAUSE CURE
WATER PUMP REPAIR GUIDE
WATER PRESSURE LOSS DIAGNOSIS & REPAIR
WATER PUMP SHORT CYCLING
WATER SOFTENERS & CONDITIONERS
WATER TANK REPAIR PROCEDURES
WATER TANK: USES, TROUBLESHOOTING
WATER TESTS, CONTAMINANTS, TREATMENT
WATER TREATMENT EQUIPMENT CHOICES
WELLS CISTERNS & SPRINGS
WELL CHLORINATION & DISINFECTION
WELL FLOW RATE
WELL WATER PRESSURE DIAGNOSIS
WELL YIELD IMPROVEMENT
WINTERIZE A BUILDING
Troubleshooting deteriorating water pressure in buildings: this article describes how to diagnose slow water pressure loss and erratic well pump behavior. When water pressure seems to keep dropping after the well pump has stopped, what's wrong? How do we fix it? How to diagnose and fix erratic well pump or pressure control switch behavior. We explain the difference beween the pump pressure control switch and the pump relay switch (not all homes have a pump relay). And we give a step by step diagnostic procedure for falling water pressure trouble.
Green links show where you are. © Copyright 2014 InspectApedia.com, All Rights Reserved.
How do we diagnose slow pressure or loss of water pressure in a building after the well pump has cycled off, and what are the common causes and repairs for erratic well pump or pressure switch behavior?
This article discusses water pressure that falls slowly when it should be more steady - diagnosis & cure. Readers whose wells simply run out of water should also see WELL QUANTITY FLOW TEST PROCEDURE and see WELL YIELD IMPROVEMENT.
Readers whose water pressure seems to periodically just get very bad or stop entirely should see WATER PRESSURE INTERMITTENT, or to start at home page for this subject, see WATER PRESSURE LOSS DIAGNOSIS & REPAIR
Short cycling of a well pump (see WATER PUMP SHORT CYCLING) is also a type of "intermittent lost water pressure" except that water pressure fluctuates between stronger & weaker rapidly, perhaps every few seconds. Short cycling has several different causes, including a partly-clogged sensor on the pressure switch (blocked by debris, water pressure is slow to enter the pump control, and slow to leave it). A similar problem can happen at a pressure gauge, making the gauge slow to register an increase and then to bleed down, showing a pressure drop more slowly than the actual water pressure drop.
Meaning of a Slow Responding Well Pump Pressure Switch
A slow response of a well water pump pressure switch (WATER PUMP PRESSURE CONTROL SWITCHH) and/or pump relay control (WATER PUMP RELAY SWITCH) to the actual water pressure suggest a blocked pressure switch sensing port - due to debris in the water or hard water.
Note that water pump relay switches are often installed when the well pump is actually down in the well (a submersible pump) while in-building water pumps (1 line or 2-line jet pumps) will not usually require the heavy-duty pump relay control. Instead the in-building pumps are controlled directly by the pressure switch.
Meaning of Building Water Pressure Drop to Zero
A building water pressure drop to zero when the well pump is still able to switch on and restore water pressure (if the gauge is accurate - see WATER PRESSURE GAUGE ACCURACY) suggests a bad foot valve or bad check valve that is letting water pressure drain back into the well. If building water pressure is lost entirely and does not immediately recover when the pump turns on, see WATER PRESSURE LOSS DIAGNOSIS & REPAIR.
When building water pressure appears to drop after the pump is turned off, some causes include
Sorting Out the Job of the Pressure Switch vs. the Pump Relay Switch
We were unsure about the "clunk" reported by a reader as an intermittent sound at the pump relay, but a possible explanation would be confusion between what the little water pressure switch is doing versus what the heavy duty pump relay switch is doing.
Normally, the water pressure at the pressure sensing switch is what turns the pump on and off, either by directly switching the pump on and off in response to sensing the cut-in or cut-out pressure at the pump or water tank, OR indirectly by turning on and off a heavy-duty pump relay switch that is used to turn higher horsepower and thus higher amperage-drawing (submersible) well pumps on and off.
Running a high-amp well pump off of a little pressure control switch will often burn up the switch contacts, or the amperage draw may exceed the rating of the pressure switch itself - that's why the relay switch is used.
So the "duty cycle of the pump" cited by our reader doesn't seem to explain this problem, though some other electrical problem in the pump wiring or controls could be causing the pump to cycle on and off while the pressure switch continues to call for pumping - such as a faulty thermal overload switch.
List of Diagnostic Steps for Slowly-Falling Building Water Pressure
Reader Question about Dropping Water Pressure
I have a residential well that is about 11 years old. I believe the pump itself is a submersible type located at the end of the pipe at the bottom of the casing in the back yard. In the house, there is a bladder type pressure tank, a control box on the wall, a pressure switch and guage on the water pipe. After that is the water filter and water softener. Then it branches out to the house.
My Well pump is short cycling. Here's what I see:
Looking at the pipes in the basement where the well attaches to the house water system, I watch the water pressure guage. Its at 60 psi. I open a facet and run some water until the well pump turns on. The pressure guage is about 40 psi when the pump turns on. I stop running water.
The pressure rises to about 55 psi and the well pump turns off. I watch the pressure guage and it slowly drops a few psi while maybe 10 seconds have passed.
The slow water pressure drop problem and its diagnosis are discussed in this article beginning at WATER PRESSURE FALLS SLOWLY, ERRATIC PUMP.
Also see WATER PUMP SHORT CYCLING.
The pump turns back on and pumps up to about 58 psi and turns off
I watch the pressure guage and it slowly drops a few psi while about 10 more seconds pass. The pump turns back on and pumps up to 60 psi and now I hear a solid "clunk" noise in the well control (relay) box on the wall and the pump turns off. This time, there is no drop in pressure and the pump does not turn back on unless I use more water.
I found this information about the "foot valve" and "well pump pressure" that may help explain the cause but what is the "clunk" noise and why doesn't the clunk happen every time the pump cycles? Does the clunk only happen when the foot valve is engaged? Or is the well pump unable to produce 60 psi every time and has its own shut-off at the pump itself?
Well piping foot valve leaks:
In some cases a defective foot valve in the well can cause water to drain back out of the building system into the well, dropping pressure in the water tank and causing the pump to run mysteriously. The "foot valve" is an anti-siphon device intended to hold water in the pipe that rises up inside the well after the pump has shut off. If the foot valve is damaged you'll need a plumber to pull the well line and replace the valve. The foot valve itself is an inexpensive part but pulling the well line can be costly. On the author's well the foot valve lasts typically about 20 years. See WELL PIPING FOOT VALVES.
Well pump pressure:
Exceeding well pump pressure capability: If you set the cut out (stop pumping) pressure higher than the water pump
is capable of reaching, the pump will just keep running indefinitely until it burns up or blows a fuse or trips a
circuit breaker or overheats. See WATER PUMP PRESSURE CONTROL ADJUSTMENT.
General Tips for Diagnosing Water Pressure Problems
This sketch, courtesy of Carson Dunlop, shows five factors that affect the water pressure and flow in a building. What the sketch has not included are water pressure, quantity, or flow problems that originate at the well, well pump, or water pressure tank. Here is our comprehensive guide to diagnosing bad water pressure.
If you have no water pressure at all, see No Water Pressure and see the other water pressure diagnostic articles listed just below.
If your water pressure is intermittent, starts and stops, or varies in pressure, see WATER PRESSURE INTERMITTENT and see the other water pressure diagnostic articles listed just below.
If there is some water pressure but the pressure and/or flow are poor? See the diagnostic articles listed just below.
Keep in mind that if water is running elsewhere in the building (another shower, sink, dishwasher, clothes washer, garden hose, etc) then the water pressure you will observe at your location will usually be reduced.
If you have good cold water pressure but not enough hot water pressure or hot water quantity, see HOT WATER IMPROVEMENTS
If you have good water pressure at some fixtures but not at others, you probably have a clog in building piping (such as due to mineral deposits, rust, or even excessive solder in new work), or mineral and debris clogged strainers at faucets and shower heads (check these first). Also see WATER PIPE CLOG DIAGNOSIS and WATER PIPE CLOG REPAIR.
For our complete water pressure and pump, well, and piping problems diagnostic article list, see WATER PRESSURE REPAIR GUIDE & COSTS and WATER PRESSURE LOSS DIAGNOSIS & REPAIR. Separately we also provide a WATER PRESSURE PROBLEM DIAGNOSIS TABLE. The following articles pertain if you have a private well, pump, and tank system for your building or if your incoming community water supply pressure and flow are just too low to start with:
Frequently Asked Questions (FAQs) about deteriorating well water pressure or flow rate
Question: why would my submersible pump system recovery time have gotten so much longer?
I have a well with a pump at 60'. Recently the pump "recovery" time has increased dramatically. When I check the ohms on the electric it appears that there is no problem and when checking amps when running, it is drawing about 10 amps. What can the problem be? - C H Werner
Reply: some causes of dropping water delivery rate from the well
In addition to the diagnostic articles listed earlier in the article above, you should check out our two approaches to diagnosing loss of water pressure: WATER PRESSURE LOSS DIAGNOSIS & REPAIR and in table form, WATER PRESSURE PROBLEM DIAGNOSIS TABLE.
If your well pump is running longer to reach the pressure control switch cut-off point, I can suggest several causes (listed in the above article and table) that you will want to investigate:
Questions & answers or comments about water pressure that falls off slowly or deteriorates.
Check the FAQs just above, try the search box just below, or if you prefer, post a question or comment in the Comments box below and we will respond promptly.
Search the InspectApedia website
HTML Comment Box is loading comments...
Technical Reviewers & References
Related Topics, found near the top of this page suggest articles closely related to this one.