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Life Expectancy of Drinking Water Wells, Water Pumps, Water Tanks WaterAPedia © Enter your search terms Submit search form   Search This Website - InspectAPedia.com

• What is the expected life of a drinking water well, water pump, or water tank? How long should a well last?
• What factors affect the life expectancy and continuous water yield of different types of wells?

This article describes factors affecting the Life Expectancy of Drinking Water Wells, Water Pumps, Water Tanks. Readers of this document should also see Water Tank Types and before assuming that a water problem is due to the well itself, see Water pump and pressure tank repair diagnosis & cost an specific case which offers an example of diagnosis of loss of water pressure, loss of water, and analyzes the actual repair cost. Our site offers impartial, unbiased advice without conflicts of interest. We will block advertisements which we discover or readers inform us are associated with bad business practices, false-advertising, or junk science. Our contact info is at inspect-ny.com/appointment.htm.
© 2008 Daniel Friedman, All Rights Reserved. Information Accuracy & Bias Pledge is at below-left. Use the links at page left to navigate this document or to go to Other Website Topics. Green links at left show where you are in our document & website.

Life Expectancy of Water Wells

How Long Should a Water Well Last?

The life expectancy of drinking water or irrigation wells is quite variable and depends on a number of factors which we describe here. We welcome suggestions or reports of personal experience with the life of wells, pumps, and water tanks.

Here are some factors that affect the life of a well - by which we mean the continued ability of a well to yield water to its users. First let's make clear that we're talking about the well itself, the hole in the ground and its ability to give an adequate quantity and flow rate of drinking water, not the equipment used to get water out of the ground, such as the water piping, water pump, pump controls, water tank or valves. The issue of water potability - can it be used for drinking - is separate from the ability of the well to deliver water at all, but beware: a well with a good flow rate and good potability can change in both of those factors. See WATER TESTING for a discussion of contaminants that occur in drinking water, how to test for them and how to remove them.

• General Geographic Location of the Well: In what part of the country was the well drilled and what are local ground water conditions. At the rim of the Grand Canyon in Arizona a successful water well may need to be drilled to 900' to obtain a successful water delivery rate.
• Local geography and groundwater conditions - exactly where was the well drilled and what are local water table conditions. For example, a 45' deep well drilled near Lake Superior in Minnesota and tapping a low mineral content aquifer may last for generations while a similarly deep well on a hilltop in the Hudson Valley of New York state, drilled in a new development where many wells are suddenly tapping an existing aquifer may suddenly fail after only one year (see more on this cause below).
• Seasonal Fluctuations in Local Water Table in some areas, such as a drop in the level of groundwater during the dry season or during droughts, can result in a reduced well recovery rate or complete loss of well water. Open the well casing to locate and record distance from ground level to the top of the water. Compare this level at different seasons (after the well has been at rest and had a chance to recover).
• Type of well: dug well, driven point well, or modern 6" steel casing-lined drilled well.
• Hand Dug Wells: some dug wells dug in the 1800's still deliver water but no longer can deliver water of acceptable potability as surface runoff contaminates these. Hand dug wells are discussed in more detail at Hand Dug Wells.
• A modern drilled well may deliver water for generations if it taps a good aquifer with low mineral content; The same modern drilled well, deep or shallow, may fail suddenly when someone nearby drills a new well that taps and draws down the same local aquifer; or nearby road blasting can cause new rock fissures to open up sending silt or other contaminants into a previously well functioning well. Modern drilled wells, of various types, are discussed in detail at Drilled Wells - steel casings.
• Driven point wells often have rapid reduction in water flow rate, depending on the type of soil into which the driven point was inserted. Even in areas of sandy soils where these shallow wells are frequently used, water quality is questionable as surface contaminants easily enter the water supply, and water quantity is unreliable in areas where the water passage holes in the driven point become easily clogged with debris. Driven point wells are illustrated and discussed further at Driven Point Wells.
• Springs as a water supply can last for generations but as with hand dug and driven point wells, are increasingly exposed to pollution from surface runoff and high level ground water. In Mexico's San Miguel de Allende, the mountain spring which caused the village to be sited in its present location in the 1500's still produces water sufficient to operate fountains and a public laundry in the year 2007. (However most of the city's water is produced today by nine modern drilled wells and water for agriculture is provided from a reservoir, la Presa.) Springs as a water supply are discussed in deatil at Springs as Water Supply.
• Seasonal fluctuations in ground water level and long term changes in the aquifer
• Mineral level and type of minerals in water supply, or amount of sediment in the water supply are important features in the life expectancy of a water well. In areas of hard water, minerals in the water tend to clog the rock fissures through which water flows into the well - harder water clogs the fissures faster, reducing well output. Note that a process called "hydrofracing" (or similar terms) uses frozen CO2 or other measures to "re-open" clogged rock fissures to increase well yield. The nice thing about these processes is that their practitioners usually offer that if they cannot increase the well yield there is no charge. (In the 1930's and earlier, people used dynamite to re-open clogged low-yield wells - a more dangerous process as well as one which risked collapsing the entire well.)

In sum, there is no simple short reliable answer to how long a water well will continue to give good quality and acceptable quantity of water, but our experience is that driven point wells have minimum flow and shortest life in many areas as the well point clogs, and driven point or drilled wells into bedrock in areas of very high mineral content water may begin to show clogging and reduced water flow in as little as a decade.

Ask about local water conditions: Ask your neighbors, local water testing laboratories, local well drillers, and plumbers what they've experienced with well drilling success in your immediate neighborhood. At what depths is an adequate water flow rate usually found? What contaminants have been found in wells in the area for which you should be particularly alert? How are local wells affected by seasonal or longer term changes in the water table?

WELLS CISTERNS & SPRINGS describes different types of wells and shows photographs of what they look like.

Life expectancy of water tanks and water tank controls

A water tank or plumbing valve may last 5 - 20 years depending on its materials of construction, water corrosivitiy, operating pressures, and similar factors.

See WATER TANKS HOW THEY WORK which includes a discussion of the life expectancy and common modes of failure of water tanks.

Life Expectancy of Water Pumps - varies by pump type, usage, and other factors

How Long Does a Water Pump Last?

Jet Pump Life Expectancy: 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.

Submersible Water Pump Life Expectancy: 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.

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.

Which Parts Wear Out on Water Pumps?

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. A submersible pump includes these two major assemblies (electric pump motor and water pump assembly) and adds an internal check valve.

• Pump bearings
• Pump impeller or rotary vanes that move water
• 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 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. To reduce the electricity usage and operating cost of any water pump motor, wire the pump to operate on 240V rather than 120V. Most pumps, except the very smallest models, can be wired to run at either voltage level.
• 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

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 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.

Life expectancy of Well Casings, Well Piping, Foot Valves, Water Pump Wiring, Well Plumbing Connections

• Well casings: modern drilled wells for residential use typically include a 6" diameter steel casing which is inserted into the drilled well and down into bedrock. The casing is sealed around its exterior to keep (often unsanitary) surface runoff or surface contaminants out of the well interior. Mechanical damage can cause a crack in the well casing; this happened to a well at our laboratory when nearby roadwork included rock blasting. It might be possible to repair a cracked well casing but often the crack leads to contaminated water and the need to drill a new well.
• Air leaks: Well piping or equipment can develop an air or water leak and stop delivering water or reduce water delivery at any time.
• Galvanized water pipes often last 20-40 years before becoming leaky, but when used to conduct water which corrosive leaks develop earlier, and when used to conduct water which is high in mineral content, such piping may clog quickly. Hot water piping tends to clog faster than cold water piping where water mineral content is high, and clogs often occur at hottest sections of piping such as close to a water heater or inside of a tankless coil used to produce domestic hot water.
• Plastic water piping such as the commonly used black ABS well piping used to bring water up out of a well and to the building it serves is very resistant to mineral clogging, corrosion, and leaks, except for poorly-made connections between the piping and various plastic elbows or unions, or from failures due to mechanical damage: we've seen loss of water supply traced to a plastic water pipe which was damaged during backfill, for example. Some types of plastic water piping used in-homes may be damaged by a high chlorine content in the water, particularly PBS or polybutylene piping which was previously the subject of some class action litigation. Modern PBS connectors have been redesigned to avoid this concern.
• Copper water piping is not usually used inside of a well nor between a well and the building but is commonly used for in-home water piping. The corrosivitiy and mineral content can affect the life of copper piping as can the quality and thickness of the copper itself.
• A well's "foot valve" or "pichanca" in Latin America, is used at the end of piping inserted into a shallow or deep well which is pumped by an above-ground one line or two line jet pump. The foot valve eventually fails, leaking water out of the rising pipe back into the well and thus losing prime on the pump - possibly leading to loss of water supply. This is not a problem with the well itself but could be mistaken for a well failure. The repair is to pull up the piping out of the well and check and replace the foot valve. If your pump is losing prime and you have this type of equipment remember to check the foot valve as well as checking for leaks in the piping in the well itself.
• Water pump wiring especially for submersible pumps, and the pumps themselves are vulnerable to damage from lightning strikes. It's possible that the combination of electrical wiring and the steel well casing are attractive to lightning, particularly when the well casing extends above ground level (as is common practice with modern drilled wells). Electrical surge and lightning protection systems are available for installation (usually at the electrical panel) to reduce the risk of well wiring or pump damage from lightning.

Water Tank Maintenance & Repair Chapter Index

Use links just below or at the left of each of the pages at our website to navigate this document or to view other topics at this website. Green links show where you are in our document or website.

PLUMBING TOPICS
OIL TANKS
SEPTIC SYSTEMS
WATER PRESSURE REPAIR GUIDE & COSTS
WATER PRESSURE LOSS DIAGNOSIS GUIDE
  WATER PUMP PRESSURE CONTROL ADJUSTMENT
  WATER PUMP PRESSURE CONTROL REPAIR
WATER PUMPS & TANKS & WELLS
WATER PUMP CONTROLS & SWITCHES
PUMP TYPES & LIFE EXPECTANCY
WATER PUMP & TANK SAFETY
WATER SUPPLY & DRAIN PIPING
WATER TANK TYPES: WATER, OIL, EXPANSION, ALL
WATER TANK LIFE EXPECTANCY
WATER TANK REPAIRS
WATER TANK AIR, HOW TO ADD
WATER TANK REPLACEMENT
WATER TANK PRESSURE CALCULATIONS
WATER TANK SIZE & VOLUME
WATER TANKS HOW THEY WORK
WATER TESTING
WELLS CISTERNS & SPRINGS
WELL LIFE EXPECTANCY

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