Life Expectancy of Water Pumps - varies by pump type, usage, and other factors
In this article we discuss how long you can expect a water pump to last and what factors affect its life. Specifics of different types of water pumps can be read in detail at these articles:
An above-ground one line (shallow well) or two line (deep well) jet pump often operates for a considerable range of
years, as few as 4 years or as many as 15 or 20 years before needing replacement.
A typical well pump life expectancy (lumping both the electric
pump motor and the pump assembly together) is about 10 years in the U.S. and Canada, and about 5 years in Mexico and Central America.
A submersible well pump, perhaps because the motor is kept cool by being immersed in well water,
can also have a considerable range of life expectancies depending on the variables which we list below.
A submersible pump operating in low-sediment
water may have a 15 year life while the same pump in high sedimented water and without adequate sediment and check valve protection may fail in
5 or 6 years.
At left our sketch of a types of well water pumps is courtesy of Carson Dunlop. The drawing shows the key differences between a one line jet pump, two line jet pump, and a submersible water pump.
Factors Affecting the Expected Life of a Well Water Pump
Water Pump duty cycle: a water pump which is called-on to run just a few times a day will have a considerably longer life than the same pump under heavy or continuous use. One of the reasons that owners install
a larger or captive-air bladder-type water pressure tank is to extend the water draw-down cycle and thus reduce the frequency of turning the water pump on and off.
Water Pump electric motor horsepower or motor size: for the same application and workload, a larger electrical motor, for example a 3/4 or 1 HP (horsepower, or CP, caballo podre in Latin America) motor
will usually outlast a small fractional 1/8 or 1/4 hp electrical motor.
Water pump motor quality will affect how long the pump's electric motor (or any electric motor) will last. Variables include the type and quality of electric motor bearings and its lubrication requirements.
Where an electric motor is manufactured, even when it claims to be the same brand, can make a significant difference. For example according to our Mexican consultants, electric pump motors made in Mexico sometimes
perform less durably than a similar motor manufactured to U.S. standards.
Water sediment is a major wear factor on the pump assembly itself (as opposed to the electric motor that drives the pump). Sediment in water acts as an abrasive that wears pump bearings and other
moving parts.
Quality of Water Equipment Installation: can make a big difference in the life of the water supply equipment. Installers who simply hook up a pump and wiring, with no understanding of the importance
of proper location of check valves, filters, proper electrical wiring, etc. are likely to be providing a shorter-lived water supply system.
What looks like "a well pump or water pump" actually is a collection of major assemblies and more numerous minor parts.
The major assemblies on
an above ground water pump (such as a one line or two line jet pump) include the electric motor that drives the pump and the actual pumping assembly
that moves water from the well to the water pressure tank and on into the building.
You an see the pump impeller in the sketch at left. Hard water, dirt and sediment, little stones, or other debris can damage this component: the pump motor may run just fine but less water pressure or flow may be delivered by the pump.
A submersible pump includes these two major assemblies (electric pump motor
and water pump assembly) and adds an internal check valve.
Pump impeller or rotary vanes that move water - see sketch above
Pump motor bearings inside the electric motor that drives the water pump
Internal pump check valves
Pump control switches which are normally physically separate devices, also wear or fail, becoming clogged with sediment or suffering burned electrical contacts. See WELL PUMP PRESSURE CONTROL ADJUSTMENT for details.
How Can We Maximize the Life Expectancy of a Well Water Pump?
Install a sediment filter ahead of the water pump in above ground water pump installations. Most well equipment installers place a filter after
the water pump, or even after the water pressure tank rather than ahead of these components. If the well water has a high sediment level placing a sediment
filter upstream or before the water passes through the water pump will extend the pump life significantly.
Install check valves where they will protect the water pump from loss of prime and having to work as hard to restore prime. For example, while
most submersible pumps contain their own integrated check valve, installing a second check valve at the top of the well or further in the well piping
reduces the load on the water pump's internal valve, protects against loss of prime in the well piping, and extends the life of the water pump itself.
Select a pump motor horsepower or size which is appropriate for the anticipated usage or duty cycle for the well and pump installation. In general
a larger motor will outlast a smaller pump motor. Match the pump output rate to the safe well yield. See Well Yield: Well Flow Rate. This avoids water pump cavitation that can damage the pump.
Use a well drawdown low water cutoff device or well tailpipe: Install a WELL PIPING TAIL PIECE (or well low water cutoff) or a well drawdown pump protection tailpiece in the well itself if the pump is likely to encounter seasonal low water table conditions that drop the well safe yield point, install a drawdown cutoff device or low-water cutoff device (also called drawdown protection device) in the well to protect the pump.
Wire the pump for 240V: If your pump motor and control are labeled indicating that it is permitted to run the pump at either 120V or 240V, and if you are installing the pump new, there are some advantages to wiring the pump to operate
on 240V rather than 120V. The motor will start more easily and you might improve the pump motor life.
Most well pumps, except the very smallest models, can be wired to run at either voltage level. The higher voltage will make it easier for the pump to start. The efficiency of the water pump and its operating cost will be about the same regardless of the voltage used. See Efficiency of 120V vs 240V Equipment for an answer to the question of whether or not changing a well pump from 120V to 240V will save in operating cost. (Basically, no.) Also See DEFINITIONS of ELECTRICAL TERMS for definitions of Amps, Volts, Watts, Ohms, etc.
Perform necessary pump maintenance: some water pumps require inspection and replacement of internal parts such as bearings or impellers
as often as after just four or five years of use. While it may be possible to ignore this maintenance for a while, the effect may be to so wear
the pump or pump motor parts that complete pump or pump motor replacement are necessary.
Check available voltages on the pump motor circuit. We speculate that some electric motors will fail sooner if they are required to
frequently operate at voltages lower than their design voltage range.
Maintain the water pressure tank: a water pressure tank which has lost its air charge and is short cycling is very hard on and
shortens the life of a water pump. See SHORT CYCLING WATER PUMPS
Install a Smart Tank or other water pressure regulation device that regulates water flow in the building to reduce the water pump cycling rate
See WATER PUMPS & TANKS for a discussion of common failures and
repairs on water pumps and water tanks.
Life expectancy of water pump controls and switches
See WELL PUMP PRESSURE CONTROL ADJUSTMENT and its companion
articles which include
a discussion of the life expectancy and common modes of failure of water pump and tank pressure controls.
Other Types of Water Well Pumps
Kinetic water ram water pumps
A kinetic water ram pump uses the force of running water in a stream combined with the principles of hydraulics to lift water as much as 50 meters from the pump location. The water ram was invented in 1780 by Frenchman Joseph Michael Montgolfier.
Since surface or stream water is unlikely to be sanitary in most locations, water ram pumps are used mostly in agriculture to move stream water to fields for irrigation.
A very different water ram, a "kinetic water ram" pump using compressed air to clear clogged building drains is available and is discussed at CLOGGED DRAIN DIAGNOSIS & REPAIR. That kinetic water ram is a drain clearing tool not a water pump.
Photo & Description of Hand Pumps and Windmills or Mechanical Pumps for Pumping Water
A variety of mechanical pumps has been in use for thousands of years, including human or animal-rotated water wheels to lift water from a river or stream and more recently piston-type pumps that combine a vertical rod and handle to lower and then lift a piston in a pipe or tube, "sucking" water from as deep as 20 feet to the surface.
A hand pump on a well will have trouble lifting from much depth. Still deeper wells were traditionally accessed by the simple bucket and rope method.
Photo & Description of Piston Type Well Pumps
A mechanical version of the hand pump on wells (shown just above) was able to lift from somewhat greater depth, perhaps as much as 20 feet.
The well pump motor and its vertically-operated piston was set directly over the well casing as we show in the photo of an old, discontinued piston well pump.
In our photo you can see the large pulley wheel on the right side of the vertical piston pump, but the drive belt and motor that drove the pump have been removed.
What is Well Pump Cavitation?
Well pump cavitation describes the entry of air or gases into the mechanical parts that are trying to move water through a water pump. The presence of air or other gases in the actual pump chambers or around the water pump impellers leads to overheating of these parts and mechanical damage to the pump moving parts. Cavitation can also cause the pump to have to work longer to satisfy the water demand and thus its electric motor to overheat, also reducing motor life.
Cavitation inside of a water pump can be caused by several problems including:
Inadequate well yield: if the yield of a well drops for any reason, trying to pump water beyond the safe yield of a well pump can introduce air into the well pump and water piping.
See Well Yield: Well Flow Rate where we define safe well yield. Also see AIR DISCHARGE at FAUCETS, FIXTURES.
Oversized pumps that mis-match the well flow rate to the pump's output rate can also cause the pump to form a strong vacuum inside the pumping chamber around the pump impeller. The vacuum, in turn, causes dissolved gases in the water itself to leave solution and return to bubble form.
Low Water Cutoff Devices and Well Tailpieces for Well Pump Protection on a Low-Flow-Rate Well
For details about well pipe tailpieces, tail pipes, or other low water cutoff devices that protect the well pump from damage when the well flow is too limited, please see our compete article at WELL PIPING TAIL PIECE. Excerpts are just below.
When the well pump's capacity is known to exceed the flow rate of the well, a tail pipe, tail piece, or low water cutoff control is installed to protect the pump from damage.
The well piping tailpiece (also shown in this sketch) permits the in-well water pump to continue to run by recirculating well water within the pump but by halting delivery of water or slowing delivery of water to the building.
Many sources, including the Penn State School of Forest Resources recommend installing a low water cutoff device to protect a well pump that has to operate in an inadequate or low-yield well.
A still different approach that may provide some water pump protection by reducing the well pump cycling rate is the installation of a Smart Tank that regulates water flow in the building.
What are Artesian Wells & How do They Work?
Water flows naturally to the ground surface of an artesian well, pushed there by higher pressure groundwater deeper in the earth. "Artesian" refers to Artois, the region in France that gave this type of water source its name. The Latin form of Artois is Artesia.
The level of groundwater is not "flat" under the surface of the earth. Rather underground water tends to follow the contours of the ground surface.
When the underground water reservoir is actually higher than the well that taps into it, water is forced from the higher level to the surface of the artesian well.
At Sinkholes in Estonia-The Witches' Well we describe a non-artesian well that also pushes groundwater to the surface when a nearby underground river floods.
Questions & Answers regarding this article
Questions & answers about things that impact the life of a well pump or water pump.
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Air in Drinking Water, Environmental Fact Sheet, New Hampshire Department of Environmental Services, 29 Hazen Drive, Concord NH 03301 - web search 07/14/2010 original source: http://des.nh.gov/organization/commissioner/pip/factsheets
/dwgb/documents/dwgb-3-18.pdf
Kinetic water rams are described and demonstrated at waterram.com/faq.php
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
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 Ace Jet Pump Installation Manual, instructions from Water Ace Pump Co., web search 08/28/2010, original source: http://www.waterace.com/pdf/R510%20R520%20and%20R100%20Jet%20Pumps%20Manual.pdf
Consumer hotline: 800-942-3343 - instructions for the installation and maintenance of
Water Ace shallow well pump Model R510 1/2 HP
Water Ace deep well pump Model R100 convertible 1HP and
Water Ace deep well jet pump Model R250 convertible 1/2 hp.
Water Supply & Drain Piping, Wells, Pumps, Water Supply Equipment
Access Water Energy, PO Box 2061, Moorabbin, VIC 3189, Australia, Tel: 1300 797 758, email: sales@accesswater.com.au Moorabbin Office: Kingston Trade Centre, 100 Cochranes Rd, Moorabbin, VIC 3189
Australian supplier of: Greywater systems, Solar power to grid packages, Edwards solar systems, Vulcan compact solar systems, water & solar system pumps & controls, and a wide rage of above ground & under ground water storage tanks: concrete, steel, plastic, modular, and bladder storage tanks.
Cheating on water tests: Testing Water for Real Estate Transactions - make sure your water test is valid
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
Water pressure tanks - how to diagnose the need for air, how to add air, stop water pump short cycling to avoid damage - water storage water pressure tank safety.
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