Well Construction FAQs


Proper construction of a well system is critical to producing a reliable supply of good quality water. Conversely, a poorly constructed well can adversely affect both the well’s ability to produce adequate water and quality water.

The following questions and answers address key topics related to proper well construction.





I want to get a well drilled. What do I do?
Here are four steps toward getting a water well system installed by a qualified water well system professional that provides an adequate supply of good water and meets legal requirements.

Step 1—Legal requirements: Make sure you know any legal requirements relating to water well installation. Ask your local government about any required permits prior to the start of drilling—or you can ask a water well system professional if you already work with one.

To learn more, view State well construction agencies. For your state’s information, click on your state and go to the “Domestic Water Well Information” section to view the construction and licensing agencies, regulations, and laws.

Step 2—Hiring a professional: If you don’t use a particular water well system professional, the next step is to find one. A professional should have the credentials, skills, experience, and business practices in place to ensure a good job will be done. To learn more, view:

Step 3—The well location: If you haven’t built your house yet, it is best to plan for a water well before building the house to ensure the best location can be selected to produce an adequate supply of good quality water.

The actual location of a well often is determined by limiting factors such as land surface features (i.e., steep slopes and poorly drained areas) and the location of potential contamination sources such as an onsite wastewater system (i.e., a septic system).

To learn more, view:

Step 4—Determining your water needs: Work with your water well system professional to determine your daily water needs. This could affect where and how the well is constructed. Having sufficient water means the ability to meet the following needs:

  • Everyday use including drinking, cooking, plumbing (toilets, bathtubs, showers, automatic washers, dishwashers, and other automatic appliances)
  • Seasonal use including lawn and garden watering, car washing, and swimming pool use
  • Special uses such as animal watering, crop irrigation, and water treatment devices that require backwashing
  • Fire protection is a special need for which a home seldom depends on a well, since fire departments usually have access to large quantities of water.

A conservative estimate is that a house will need about 150-300 gallons a day for two to four people to meet all these demands. However, the bulk water use may be concentrated into short periods during the day, often in different areas of the house or property at the same time (i.e., laundry, bathroom, lawn). The water supply must be able to meet this type of peak demand, and a water well system professional can help you determine how to accomplish this.

Finally, other factors affecting a well’s capacity to meet water demands are the well’s:

  • Flow rate: The continuous rate at which the well yields water
  • The diameter and depth of the well: This determines a certain amount of water storage within the system itself
  • Static level: This is the level at which water stands in a well when no water is being pumped—also relating to the amount of water storage within the system.

To learn more, view:

How much does a water well cost?

Water well installation costs: The cost of a water well system can vary greatly depending on several variables. Following are the key contributors to the cost of a water well system. When considering a new well with a water well system professional, an itemized list of charges is better than a lump sum to get a clear picture of costs.

(Note: The figures used here provide a general indication and are not exact representations of costs in any locale. Costs can vary over time and by location.)

The well’s depth: As part of their overall cost structure, water well drillers apply a cost-per-foot of drilling. Recent survey data indicates that the average cost-per-foot for drilling a 4-inch-diameter well is about $24, and the average cost-per-foot for drilling a 6-inch-diameter well is about $30.

This means the depth of a well can be a big factor in the overall cost of the well system installation. Using the average costs for drilling, a 120-foot-deep, 4-inch-diameter well would cost $2,880 and a 6-inch-diameter well to the same depth would cost $3,600. Drilling a 220-foot-deep, 4-inch-diameter well would cost $5,280 and a 6-inch-diameter well to the same depth would cost $6,600.

Since the depth of a well to adequate, good quality water can vary significantly, even in a locale, it is important at the start to discuss with a water well system professional the anticipated depth of a well based on the best information available (such as the depths of area wells). It also is worth discussing the cost of drilling deeper or drilling a second well if required to ensure an adequate water supply.

Pump costs: Pumps are another significant contributor to the overall cost of a water well system. There are two primary types of pumps—submersible pumps, which are submersed in the water down in the well, and jet pumps, which are on the surface of the ground in proximity to the wellhead.

Recent survey data indicates that the cost of a typical household submersible pump ranges between $3,000 to $3,200—and the cost of a typical household jet pump ranges from about $1,545 to $1,570. While either type of pump might work satisfactorily in some wells, the performance demands of a particular well might suggest one type of pump over the other. This should be discussed with your water well system professional or a pump installation specialist. Learn more about pumping systems®.

Other costs: Other typical costs charged for water well system installations are:

  • Cost of casing per foot (Casing is the vertical pipe inserted into the drilled hole.)
  • Other materials used in the well or the drilling process (i.e., grout, the well cap, and the drive shoe)
  • Costs of operations other than drilling (i.e., grouting, further development of the drilled hole, test pumping, and well disinfection)
  • Cost of properly abandoning a well should it prove necessary (for instance, if saltwater is encountered and another site for the well is selected)
  • Any other costs related to the entire well system (i.e., the water distribution line to the house and the pressure tank).

Final considerations:

  • Consider the professional’s judgment in solving unforeseen difficulties, and discuss unforeseen costs
  • If original construction plans must be changed, discuss the options with the contractor
  • Do not expect the contractor to work for free if the well does not fulfill expectations
  • When it comes to charges, a good written contract is the best protection for both the well owner and the water well professional. Learn more about written contracts.

What should I consider in hiring a water well system professional?

There are several criteria you can use to evaluate and select someone.

You should know that there are both:

  • Full-service water well system companies that drill the well, install the pump, and install the rest of the system including components such as water pressure tanks and water treatment, and
  • Companies that do part of the work, such as drilling the well or installing the pump.

Whether you use one or more companies, always use a professional who can satisfactorily meet the criteria below.

Also, prior to selecting a water well professional for a job, it is a good idea to obtain information about several contractors in the area before making a choice.

Qualifications, skills, and experience: Check whether the contractor is licensed by the state. Not all states require licensing. To check, click here, then click on your state and go to the “Domestic Water Well Information, Licensing / Registration of Professional” for a contact person to ask.

When considering specific water well system professionals, ask if he or she:

  • Is certified by the National Ground Water Association? Learn more about certification
  • Submits well logs on the well construction
  • Has adequate equipment in good condition to do the job
  • Has adequate liability and workers’ compensation insurance to protect you
  • Is familiar with applicable health and safety codes
  • Will provide references from previous customers
  • Will furnish a written contract specifying the terms and conditions of the job
  • Is a member of the National Ground Water Association.

For help in locating water well system professionals, go to the Find a Contractor section of the National Ground Water Association website, WellOwner.org.

How do I know if a well driller is qualified and competent?

Whether a water well system professional is qualified legally to drill a well or construct a well system usually depends on whether the state requires licensing or registration.

To find out what your state requires—or to check on a water well professional—click here: State well construction agencies. Then click on your state, scroll down to “Domestic Water Well Information,” then view contact information for “Licensing/registration of professional.”

Ask your local government about any legal requirements relating to water well installation, including any required permits prior to the start of drilling.

Whether a water well professional is competent is a different question. Since there is generally no authority charged with overseeing the quality of a water well professional’s work outside of the initial well construction, it is up to the customer to exercise due diligence before engaging a professional by:

  • Checking references from previous customers
  • Confirming that the professional will provide a written contract specifying in detail the work to be done along with any conditions
  • Determining if the contractor has adequate liability and worker’s compensation insurance to protect you.
How do I know if my well will produce enough water?

If you use a water well system professional who has drilled wells in your vicinity, he may have a pretty good idea of how productive area wells are. However, it must be said that there is no assurance that a well, once drilled, will provide an adequate supply for the home it services. For a well to provide an adequate supply of water, it must be able to supply the maximum amount of water needed within the shortest period it is used.

Here are some key factors that determine whether a well can provide an adequate supply of water for a given household.

The amount of water stored within the well system itself is a key factor. The well storage amount is determined by the diameter of the well, the depth at which the pump is set, and the height of the water within the well. A well may have some limited additional water in the pressure tank and auxiliary water storage tanks.

Another key factor is the water flow into the well. Water flow is defined as the volume of water entering the well at a given depth in gallons per minute.

Two other factors key to determining whether a well can provide an adequate supply of water is the peak load and peak load time. Peak load is the amount of water used during periods of the day when demand is highest; peak load time is the length of time in which the peak load is to be delivered.

You can discuss these variables with a water well system professional to better determine what your well system must provide to meet your household water demands. You can do some of these calculations online by clicking here.

How do I know if my well will produce good quality water?

If you use a water well system professional who has drilled wells in your vicinity, he may have a pretty good idea of the water quality for area groundwater. Water quality issues can be aesthetic, involving an objectionable appearance, taste, or odor. Other water quality issues can present a health risk yet be invisible, tasteless, and odorless, such as arsenic, nitrate, and radon. Substances that present health risks can be naturally occurring or manmade contaminants.

In addition to asking a water well system professional about area water quality, consider asking the local county or state health or environmental health department about your local water quality—particularly whether there are known health risks associated with area groundwater.

Also, sometimes groundwater contamination can be very localized, for instance, surface contamination entering the groundwater through an improperly abandoned well. So, doing an assessment of the area around where the wellhead will be can reveal actual or potential risks to one’s future water supply.

Learn more about water testing and groundwater protection.

Where on the property should the well go?

There are multiple factors that determine where best to locate a well. They include:

  • Topography—Generally, locating the well on higher ground is better to minimize the potential for standing water around the wellhead. Standing water can potentially infiltrate the well if the grout seal around the well casing is not watertight.
  • Separation from potential hazards—Most states and many local governmental jurisdictions have water well construction codes. Often these codes specify minimum separation distances between the wellhead and potential contamination hazards such as septic drain fields, animal enclosures, fuel storage tanks, roads, and fertilizers, pesticides, and herbicides.
  • Geology—Water-bearing geologic zones are called aquifers. Data from previously drilled wells or other sources may provide some direction on where on a piece of property a new well should be drilled.
  • Service access—Like any mechanical system, a water well system requires periodic maintenance and repair. It is therefore important to locate the well where it can be accessed by a drill rig or pump hoist, for instance, for servicing.

When it comes to the exact location of a water well, the water well system professional should at a minimum consider the preceding factors.

Some people by tradition use a “water witcher” or “water dowser” to pick a location for a well—where an individual uses a forked stick purpotedly sensitive to the presence of water underground. The National Ground Water Association does not recommend this.

Water witchers/dowsers have been tested in unbiased experiments, and their success at locating water has been no better than random odds. Often other factors such as topography, separation from potential hazards, geology, and service access are more important drivers of where to locate the well.

To learn more, view:

How long does it take to construct a new well system?

The well construction process can be divided into two major phases:

  • The drilling of the well
  • Construction of the rest of the system, which includes installation of the water distribution line to the house, the pump and associated wiring, the pressure tank, and any water treatment equipment that may be necessary depending on the water quality.

Drilling the well can take hours or days, depending on how deep the well needs to be and the geology through which it is being drilled. The type of drilling technology also depends on the geology through which the well is being drilled. Common drilling technologies for household wells include rotary, cable tool, down-the-hole, and reverse circulation drilling.

Well depths can range from less than 100 feet to 500 feet or more.

Installation of the pump and pressure tank tend to be routine as is installation of the water distribution line, although the work involved in the latter can depend on the length of the distribution line from the well to the house.

Some but not all water well system professionals install water treatment equipment. Treatment can involve one technology or a series of different technologies, depending on what or how many substances are being treated in the water. Some well water needs no treatment at all if the groundwater quality presents no objectionable appearance, taste, or odor issues or health risks.

What happens to all the debris from the drilling process?

Just as drilling a hole in a piece of wood creates cuttings, drilling a well also creates debris. Failure to clean the borehole of such debris can result in poor quality turbid water.

An important part of well construction is the well development, a process which removes loose material resulting from the drilling process and leaves the borehole more clean, stable, and permeable so that water flows more freely into the well. Proper well development can sometimes make a poor well a good one in terms of water quality and water production.

Can I drill my own well?

In most cases, the answer is no. Laws and regulations usually require an individual drilling a well to be licensed or registered. In some states, a water well driller must pass a written test and have certain credentials to drill a well.

Regardless, the National Ground Water Association does not recommend that individuals drill their own wells. Rather, a qualified water well system professional should be used. There is a good reason for this. A drilled well provides a direct conduit into the groundwater. If a well is not drilled properly with all the necessary sanitary seals in place, the well could provide a direct pathway for surface contamination into the well and the aquifer.

Learn more about the licensing and registration of water well system professionals.

Can I share a well with a neighbor?

It is not uncommon for two or more families to share a well. If you are thinking about a shared well, there are at least several matters that you should consider.

A shared well agreement: A shared well may make sense, for instance, if one’s property is not suitable for drilling a well while a neighbor’s property is suitable. Remember, however, that water is not the only thing you will be sharing. Sharing in the ongoing operation and maintenance of the well—as well as monitoring water quality and good groundwater protection practices—would normally be expected of all participants in the well.

To protect the interests of all involved, a shared well agreement is advisable. An agreement should be drafted by an attorney, such as a real estate attorney or another attorney proficient in drafting water agreements. Areas commonly addressed in such agreements include:

  • Ownership
  • Cost of construction
  • Cost of maintenance
  • Water line easements
  • Maintenance and repair of pipelines
  • Prohibition practices, such as construction or land-use in proximity to the wellhead.

Typically, privately owned water wells serving residences are not regulated on an ongoing basis for water quality. However, if a private well serves enough people, it qualifies as a public water system and comes under federal Safe Drinking Water Act regulation.

A public water system is defined as a system that provides water for human consumption to at least 15 service connections or serves an average of at least 25 people for at least 60 days each year. This includes water used for drinking, food preparation, bathing, showering, brushing teeth, and dishwashing. Public water systems range in size from large municipalities to small churches and restaurants relying on a single well.

Here are three types of public water systems:

  • Community water systems serve at least 15 service connections used by year-round residents or regularly serve at least 25 year-round residents.
  • Non-transient, non-community systems serve at least 25 of the same persons over six months per year.
  • Transient non-community systems serve at least 25 different persons over 60 days per year.
Are private household wells regulated?

Most private household wells do not have ongoing regulation of water quality or the well system’s maintenance. However, most states do have some limited regulation.

Three areas where private wells are most likely to be regulated are:

  • Well construction: Most states have some well construction standards. Often states adopt the well construction standards but sometimes local governmental jurisdictions will adopt more stringent construction standards. These standards are intended through proper construction to protect the groundwater and the health of persons who will be consuming the water.
  • At completion of construction: In many states, the water will be tested for certain potential contaminants that present a health risk before the water is allowed for human consumption. In some states, for instance, the water must be free of coliform bacteria, which, if present, indicates that the conditions exist for potentially harmful pathogenic bacteria. In such cases, the system would need to test free of bacteria before the state would allow the water to be consumed.
  • At property transfers: While most states don’t regulate water quality in private household wells beyond a well’s construction, some states do require testing the water if a property being purchased has a private well.

To find out your state’s private well regulations, click here, then click on your state and scroll down to “Construction,” then “Contact Information” or “Regulations.”

How do wells work?

First, the basic components of a modern water well system consist of:

  • A steel or plastic well casing, which is inserted into the borehole to keep the hole open and protect the quality of water in the well
  • A pump, either submerged in the well or located on the surface
  • A wellhead, which is the portion of the well casing that extends above the surface of the ground, is capped, and allows access to the well
  • A distribution pipe that carries water from the well to the house, and in colder climates is buried to prevent freezing but in warmer climates may be located above ground
  • A pressure tank, which stores and delivers water under pressure so that the pump need not run whenever water is used
  • Any water treatment equipment which, depending on what is being treated and how, could be located anywhere in the well system from the well borehole and the wellhead to the water distribution pipe outside the house, inside the house before the house plumbing or somewhere in the house plumbing.

A well operates much like a person using a straw in a glass of water. The straw is the well and the drinking water glass is the aquifer that holds underground water. The person using the straw is like a well pump drawing water out of the aquifer—and the person’s digestive system receives the water like a distribution pipe and removes impurities like water treatment equipment so that safe water is available to the body or, in the case of a household, the well owners.

It is important to note that a properly constructed and installed water well system has sanitary seals that prevent certain types of contamination, such as bacterial contamination, from entering the system in key areas of vulnerability. Certain well construction features also can block off subsurface water-bearing zones from contributing water with naturally occurring contamination to the well.

What are the key components of a water well?

A water well is really a water well system because it consists of numerous components—several of which can affect water quality if not maintained.

The following well system components are designed to protect water from substances that are harmful to health or adversely affect the water’s appearance, taste, or odor.

The well casing: This is the tubular structure that is placed in the drilled well to maintain the well opening. Along with grout, which seals the space between the drilled hole and the casing, the casing confines the groundwater to its zone underground and prevents contaminants from mixing with the water.

The most common materials for well casing are carbon steel, plastic (most commonly PVC), and stainless steel. Different geologic formations dictate what type of casing can be used.

The well cap: The well cap goes on top of the well casing above the surface of the ground. It should fit snugly so debris, insects, or small animals can’t find their way into the well system. The well cap should be bolted or locked so that it cannot be easily removed. The well cap also provides access to the well for servicing by a water well system professional.

Well caps are usually aluminum or thermoplastic and have a vented screen so that the pressure difference between the inside and outside of the well casing may be equalized when water is pumped from the well.

A cracked or loose well cap could allow outside contaminants, including bacteria via insects or vermin, into the well. Well owners should periodically inspect the well cap and contact a water well system professional if a problem is detected.

The pitless adapter: This connector installed underground below the frost line provides a sanitary seal between the well casing and the water line running to the house. If this seal is compromised, it could allow bacteria or other contamination into the well. A water well system professional can determine whether the pitless adapter is contributing to such water quality problems.

The well screen: The well screen attaches to the bottom of the casing, allowing water to move through the well while keeping out most excess sediment, sand, and gravel from entering the well.

There are different styles of screens, including perforated pipe, continuous slot, and slotted pipe. A water well system professional can determine which type is best suited to your well.

The following components perform other vital functions in a water well system:

The pump: Two types of pumps dominate the household well market—jet pumps, which are mounted above the ground, and submersible pumps, which are housed underwater down in the well.

Jet pumps are most often used for shallow wells up to a depth of 25 feet or so, although jet pump technology can be configured to pump water from several hundred feet deep. Jet pumps use suction created by a vacuum to lift water out of the well.

Submersible pumps can be used at shallow depths or in deeper wells. They push water up through a pipe installed in the well.

Variable speed drive pumping systems vary the speed of the pump motor to deliver the amount of water needed under pressure on demand.

The pressure tank: The pressure tank is usually located in the house, and they generally range in size from 20 to 80 gallons. These tanks deliver water under pressure so that the pump doesn’t have to operate every time water is used.

Water treatment equipment: A well owner may desire water treatment either to treat actual water quality problems or, for peace of mind, as a safeguard against possible contamination. To learn more, see the Water Treatment FAQs.

Learn more about well system components:

How do I know if I need a new well?

The best way to know if you need a new well is to get it thoroughly inspected by a water well system professional (see more on well inspections in the Maintenance FAQs). While it may not be visible from the surface, an inspection could reveal deterioration of a well that is unfixable. For example, sometimes the steel casing is so badly corroded that it can’t be replaced or lined.

Possible signs that a well system may be at the end of its useful life are:

  • A significant decrease in the flow rate of water into the well
  • Degraded water quality due to deterioration of the well system
  • A drop in the water table below the level of the well.

Again, before deciding to get a new well, have a water well system professional evaluate your existing well. The professional should be able to explain why a new well must be constructed rather than repairing the old one.

Learn more about well system inspections:

Do new wells have warranties?

The law regarding warranties on the materials and equipment constantly changes. You should review with the contractor exactly what is warranted, and for how long—and obtain any written description of warranties for your records.

You also may want to inquire of the water well system professional whether they offer an ongoing well system maintenance or well testing service contract.

How deep should a well be?

The biggest factor affecting water well depth is the geology beneath the ground surface. Finding an adequate supply of good quality water may be dictated by the location of a suitable aquifer, which is a water-bearing formation.

In a given location, there may be only one aquifer from which to choose so that the water well professional must drill to that depth. In other locations, aquifers may be layered but of differing water quality and quantity—so a decision must be made about which aquifer to tap into. In yet other locations, the best aquifer could be dozens of feet thick to 100 feet thick or more—so a decision needs to be made how far into that aquifer to drill, considering how water levels could drop in the aquifer over time if it is an area where groundwater pumping is heavy.

Information from area well logs—records of the subsurface from drilled wells—could provide an indication of the approximate depth at which suitable water may be found. The water well system professional should be able to explain what he estimates the well depth will be and why.

Understand, however, that anomalies occur in the subsurface, and there are no guarantees about the depth at which a suitable water supply will be found or whether water will be found at all. While “dry holes” are uncommon, they do happen. Some water well contractors offer discounts for dry holes. Before drilling begins, it is worth discussing with the professional the costs and next steps if a dry hole or poorly producing well results.

Can I be sure my new well will have good pressure?

For a new well, two key factors are the capacity of the pump and the pressure tank.

If a household’s water demand in gallons per minute is matched or exceeded by the pump’s capacity, water pressure should be fine. However, if the water demand exceeds the pump’s capacity, the pressure will be low.

Discuss your anticipated household water use with the water well system professional so that he can recommend an appropriately sized pump. That same information also will be helpful to the professional in recommending an appropriately sized pressure tank.

Typical pressure tanks range in size from 20 to 80 gallons. The tanks provide a limited amount of water under pressure created by the tank so that the pump doesn’t have to run every time water is used.

Factors the professional considers in deciding how to construct the well to provide adequate water under pressure include:

  • The flow of water into the well
  • The storage capacity within the well itself
  • Pump capacity
  • Pressure tank size.

Other devices that can help maintain good pressure are a constant pressure valve installed between the pump and the pressure tank, and a variable speed pump, which adjusts the speed of the pump based on the water demand.

Learn more about water pressure.

View more FAQs:

Well system maintenance
Water testing
Water treatment
Groundwater protection