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HOME > Resources > Water > Private
Water Wells ![]() About 15 percent of Americans rely on their own sources of drinking water, such as wells, cisterns, and springs. Although people have been using wells since ancient times, most are not familiar with how they work. A water well is a hole, usually vertical, drilled into an aquifer to bring water in the ground to the surface from the water-saturated zone above the bedrock.
Ground water accounts for 90% of all the fresh water in the world (excluding polar ice caps). Ground water is the water that soaks into the soil from rain or other precipitation and moves downward to fill cracks and other openings in beds of rocks and sand. An aquifer is a geologic unit (sand and gravel, sandstone, limestone, or other rock) where the amount of water is sufficient to yield usable amounts to a well or spring. Those living outside a municipality or in an area not served by public water, will typically get their water from a private well. Water wells are usually installed by professional well-drillers, with the plumbing handled by a plumbing contractor. There are two basic types of wells - shallow and deep. A shallow well is used when the water table (top surface of the ground water) is high - anywhere from 10 feet to 100 feet below the surface. Shallow wells are less expensive to dig, but rapid or large changes in water levels can be expected during periods of heavy rains. The well may go dry during a drought when the ground water table drops. They are also more likely to be contaminated from surface contaminants. There are three types of shallow wells - dug, driven, and bored. Dug Wells
A "dug well" is the oldest type of water well. A hole is dug in the ground using a shovel or backhoe until incoming water exceeds the digger's bailing rate.Typically dug wells are found next to older homes, dug before drilling equipment was readily available or when drilling was considered too expensive. Most hand-dug wells are from 3 to 6 feet in diameter (large enough for a person to work in), and shallow, usually 10 to 30 feet deep. Brick tile, stones or other material are used to line the well, to prevent collapse while allowing water to enter. Then the hole is covered with a cap of wood, stone, or concrete. If you have a dug well on your property and are using it for drinking water, check to make sure it is properly covered and sealed. Being so shallow, dug wells have the highest risk of becoming contaminated. To minimize the likelihood of contamination, a dug well should have features to prevent contaminants from traveling along the outside of the casing or through the casing and into the well.
(see Water Quality below)
Driven WellsLike dug wells, driven wells pull water from the water-saturated zone above the bedrock. Driven wells are generally deeper than dug wells - 30 to 50 feet deep, where the ground water table is within 15 feet of the ground's surface. In the proper geologic setting (areas with thick sand and gravel deposits), driven wells can be easy and relatively inexpensive to install. Lengths of metal pipes of 2" -3" in diameter are assembled and driven into the ground. A screened "well point" located at the end of the pipe helps drive the pipe through the sand and gravel. This screen allows water to enter the well and filters out sediment. The pump for the well can be located in one of two places - on top of the well or in the house. An access pit is usually dug around the well down to the frost line. A water discharge pipe to the house is joined to the well pipe with a fitting. The well and pit are capped with the same kind of large-diameter concrete tile used for a dug well. The access pit may be cased with pre-cast concrete. Although deeper than dug wells, driven wells are still relatively shallow and have a moderate-to-high risk of contamination from nearby land activities. To minimize this risk, the following steps should be taken:
(see Water Quality below) Bored Wells
Bored wells are the modern equivalent of hand dug wells. These wells are dug using an auger, scoop, dragline, or some similar machine, and are relatively large in diameter (2 to 4 feet).Bored wells are typically constructed where aquifers (water bearing geologic formations) are both shallow and low-yielding, 20 to 100 feet deep. To compensate for these low-yielding aquifers, large diameter bored wells serve as storage reservoirs to provide water during periods of high demand. Older bored wells are commonly lined with sections of clay pipe; newer bored wells are usually lined with concrete pipe. If properly constructed and covered, they can provide a satisfactory water supply and present no special hazard. Abandoned, they are as dangerous as dug wells and cisterns, and should be plugged. (see Water Quality below)
Drilled wells are deep wells - penetrating 100-400 feet into the bedrock. To serve as a water supply, a drilled well must intersect bedrock fractures containing ground water. The casing is usually metal or plastic pipe, six inches in diameter that extends into the bedrock to prevent shallow ground water from entering the well. By law, the casing has to extend at least 18 feet into the ground, with at least five feet extending into the bedrock. The casing should also extend a foot or two above the ground's surface. A sealant, such as cement grout or bentonite clay, should be poured along the outside of the casing to the top of the well. The well is capped to prevent surface water from entering the well. Submersible pumps, located near the bottom of the well, are most commonly used in drilled wells. Wells with a shallow water table may feature a jet pump located inside the home. Pumps require special wiring and electrical service. Well pumps should be installed and serviced by a qualified professional registered with your state. Sanitary Features Most modern drilled wells incorporate a pitless adapter designed to provide a sanitary seal at the point where the discharge water line leaves the well to enter your home. The device attaches directly to the casing below the frost line and provides a watertight subsurface connection, protecting the well from frost and contamination. Older drilled wells may lack some of these sanitary features. The well pipe used was often 8-, 10- or 12- inches in diameter, and covered with a concrete well cap either at or below the ground's surface. This outmoded type of construction does not provide the same degree of protection from surface contamination. Also, older wells may not have a pitless adapter to provide a seal at the point of discharge from the well. Almost all states license or register water-well installers. Most also have construction standards for residential wells. In addition, some city and county health departments have local rules and permitting. While deep wells are less likely to be contaminated, routine testing of the water supply is needed. Water testing and inspection of the well and equipment is the responsibility of the well owner. (see Water Quality below) An abandoned well is any water well that is no longer used to supply water, or is in such a state of disrepair that the well has the potential for transmitting contaminants into an aquifer or otherwise threatens the public health or safety. Underground water is constantly moving. It flows through pores in the soil and through cracks and crevices in the rock. As water moves, it picks up pollutants with which it comes in contact. Abandoned wells are a hazard to the water we all drink, even for those who use municipal water. If a well is left unsealed, the natural underground aquifer can become polluted. If the shaft of the well is left open or the well casing cracks and deteriorates, pollutants such as sewage, pesticides, fertilizers, organic or other hazardous materials can seep into underground water making it harmful to drink. Pollution is difficult to detect, difficult to control and may last for years. The water for everyone in the surrounding area, whether from public or private wells, can become contaminated. Most states require that abandoned wells be properly sealed within 30 days of connection to a public water supply or notification from the health department. A permit is generally required. SEALING A WELL Abandoned dug wells and cisterns can be plugged by pushing in the upper few feet of well lining, and filling the well to within two feet of the surface with chlorinated clean fill such as course gravel or rock, varied-sized agricultural lime, or sand. The remainder of the well should be filled with clay or clay-rich soil. Soil should be mounded slightly at the top and compacted to help offset settling. If a dug well is quite shallow, it can be pumped out and then destroyed with a bulldozer. Before sealing an abandoned well, check your with your local Health Department or water well contractor. The average cost of sealing a well varies depending on well construction and location. When the well is sealed, the driller must send an affidavit to the County Health Department stating the work has been completed. Another means of correction is to place the well back into service. If the municipality you live in allows the continued use of the well it may be possible to continue using it as a supplemental well. (see Water Quality below) A supplemental well provides water for purposes other than drinking. Watering the lawn or garden, filling a pond or a swimming pool, washing the car, are examples of supplemental well use. Supplemental wells, just like potable wells, are vertical pathways into this groundwater supply. If the supplemental well is not properly maintained, it can act as a direct channel for contaminating the aquifer.
Some areas have regulations that prohibit the use of supplemental wells. If your city, municipality, or other public water provider does not object to the use of supplemental wells, you may apply to the County Health Department to keep the well. The Health Department will inspect the well and well components, and collect a water sample. The well must be of approved construction and must produce water that is safe for human consumption. CONVERTING TO A SUPPLEMENTAL WELL Typically a supplemental well must provide approved backflow protection for the well system. Generally this means having hose bib vacuum breakers on outside faucets, a reduced pressure zone backflow device for a buried sprinkler system, and/or an approved fixed air gap for pond leveling wells. As owner of the well, you must maintain the well in compliance with all state and county well regulations. This includes completing and recording a Notice of Supplemental Well form (where required) and allowing the Health Department access to the well for inspection and sampling. A Notice of Supplemental Well filed with the County Recorder of Deeds is required in some areas. This is simply a notice that states that although your property is served by a public water supply, there is also a water well on the property. (see Water Quality below) Once the well has been drilled, the water in the well is available for use, but it must be extracted from the well and delivered under pressure to the building. This is accomplished by means of a well pump and a pressurized tank. The pump pressurizes the system as it extracts the water from the well and conveys it to the tank. The tank acts as a pressure regulator to the system by maintaining a constant outlet pressure. If repairs are needed to make the well operational or to bring it into compliance with the Private Water Supply Ordinance, you may be required to obtain a repair permit from the Health Department. The work must be completed within a specified time, usually 30 days from when your well was inspected and the problem noted. If you have a buried seal well or a well in a pit, it must be upgraded to meet the provisions of the Private Water Supply Ordinance. This type of work requires a well repair permit from the Health Department. Provisions in the Private Water Supply Ordinance mandate that supplemental wells must meet code requirements or be sealed. Water well sealing must be done by a state licensed water well contractor, or may be done by the owner-occupant with prior approval from the County Health Department. (see Water Quality below) Many homeowners tend to forget the value of good maintenance until problems reach crisis levels. That can be expensive. Maintain your well, find the problems early, and correct them in order to protect your well's performance. Keep up-to-date records of well installation and repairs plus pumping and water tests. Such records can help spot changes and possible problems with your water system. If you have problems, ask a local expert to check your well construction and maintenance records. He or she can see if your system is okay or needs work. The safety of any water supply is largely dependent on the construction and maintenance of the water system. Below is a list of common well system problems that can spell trouble if their symptoms are ignored: Most Common Water Well Problems/Causes:
As ground water moves through the ground, it dissolves some of the minerals that it comes in contact with. Those dissolved minerals give ground water its chemical character or quality. Many bottled waters come from ground water reserves. Ground water is naturally filtered by the earth that holds it. It can, however, be contaminated by pollutants that come into contact with the earth's surface. Proper well construction and continued maintenance are keys to the safety of your water supply. Your state water-well contractor licensing agency, local health department, or local water system professional can provide information on well construction. WELL CONSTRUCTION
Underground water is constantly moving. It flows through pores in the soil and through cracks and crevices in the rock. As water moves, it picks up pollutants with which it comes in contact. Protect your water supply by carefully managing activities near the water source. For households using a domestic well, this includes keeping contaminants away from sinkholes and the well itself. Keep hazardous chemicals out of septic systems. Periodically inspect exposed parts of the well for problems such as:
Installing a water-conditioning unit can reduce water hardness and iron content. Other water quality problems may sometimes be solved through disinfection of the well water distribution system. See: Hard Water vs. Soft Water High mineral or iron content may require the need for a whole house water filter. See Also: Additional Resources:
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