Frequently asked questions about driven point wells
For a free brochure containing the information on this page, contact the nearest DNR office and request publication number WS-022.
Section one: What is a driven-point well and will it work for me?
- What is a driven-point well?
- Why should I consider a driven-point well?
- Can a driven-point well supply all the water I'll need?
- How do I know if conditions in my area are good for a driven-point well?
- Is there anything I can't use a driven-point well for?
Section two: Construction, abandonment & who can construct a driven-point
well
- How is a driven-point well installed?
- What is a drive-point?
- How does the depth of the water table affect a driven-point well?
- Who may construct a driven point well?
- Who may construct a drilled well?
- What are the well construction requirements?
- What are the pump installation requirements?
- What are a well installer's responsibilities?
- What are a pump installer's responsibilities?
- Are there restrictions on where I can locate my driven-point well?
- What if I have to replace my well screen?
- How should a driven point well be abandoned?
Section three: regulation, registering and other information sources
- Who regulates driven point wells?
- What must be done after the well and pump installation are completed?
- Other sources of information on local conditions
A driven-point well - sometimes called a sand point - is a small diameter well created by driving lengths of 1-1/4" or 2" steel pipe into the ground. Threaded couplings at the ends of the pipe sections allow successive lengths of pipe to be added as the pipe is driven into the ground.
In many areas of Wisconsin, a driven-point well can be an alternative to a larger diameter
drilled well. Installed properly, it can provide an adequate supply of safe drinking water, especially for cottages and many residences.
However, because of installation limitations, driven-point wells usually are found in:
- areas having permeable sandy soils and;
- a high water table.
The above conditions make shallow groundwater, driven-point and drilled wells susceptible to contamination from land use activities. Contaminants, especially chemical contaminants, can easily migrate through permeable sandy soils, enter the groundwater, and move into a well. However, it is possible after giving careful consideration to land use in the area, to locate and construct driven-point wells that will offer protection from most types of contaminents, and especially from biological contaminents like bacteria.
Water use is another factor to consider in your decision on what type of well to install. Many homes have numerous modern conveniences such as clothes washers, dishwashers, garbage disposers and two or three bathrooms. Some people water gardens and lawns. If you anticipate needing larger volumes of water a drilled well with a submersible pump installation is usually a better, more energy-efficient, choice than a driven-point well.
The map (Figure 1) will help you determine if you are in a predominantly sandy soil
area where driven-point well installation is more likely. However, sandy soils alone will
not guarantee successful installation of a driven-point well. If the water table is deep, it may
not be physically possible to drive the well point deep enough to reach it.
Large boulders, or layers of tightly compacted soil called hardpan, may be encountered that will stop
the driving process. The well may also penetrate a clay layer making it impossible to
successfully install a driven point well. Although clay can hold a lot of water, the clay
particles are too closely packed to allow water to flow through it into a well.
Driven-point wells are allowed for the same uses as are private drilled wells, including:
- Private residential wells serving six or fewer homes and serving fewer than 25 year-round
residents.
- Non-community water supplies such as restaurants, taverns, and gas stations, etc., but
not schools. (School water supplies require approval and driven-point wells are not
usually allowed.)
- Non-potable wells that is, wells not used for drinking or sanitary purposes.
(Non-potable wells must be installed according to the same standards as potable wells).
Installation of a driven-point well begins by driving the point, attached to a single length
of pipe, into the ground. The driving is often done by hand using a post driver - a short
length of weighted steel pipe with handles. Some well point installers use mechanical,
motor-operated equipment with a tripod to raise and lower the heavy driver. Sections of
steel pipe are added as the pipe is driven deeper into the ground until a sufficient depth
below the water table is reached. A special fitting called a drive cap is threaded onto the
top of the pipe to protect the pipe threads while driving and to prevent contaminants from
entering the pipe. Sometimes a shallow starter hole is dug or augured at the ground
surface to accommodate the pipe lengths and facilitate the starting of the driving process.
Attached to the bottom of the first section of pipe is the drive point and well screen.
The drive-point well and screen consists of a hardened steel tip or point followed by 2 to 3 feet of screen. The drive-point well screen is threaded to the lower end of the first length of pipe driven into the ground. The screen allows groundwater to flow into the well while keeping the surrounding sand out. Water can then be pumped up through the pipe to the surface.
The hardened steel drive-point allows the well to be more easily driven into the ground. When
connected together, the pipe and drive-point resemble a long spear
Depth to the water table is another very important consideration when installing a
driven-point well. This is because pumping equipment varies in its ability to draw water from various depths. A shallow-well pump can draw water from a maximum depth of about 20 feet. For these shallow water table depths, 1 1/4-inch diameter well pipe is sufficient.
If the water table is deeper than about 20 feet a deep-well pump installation is necessary. Two-inch diameter pipe is necessary to accommodate a jet and packer assembly that must be installed in the well pipe itself. This assembly can draw water from depths up to about 100 feet. However, be aware that pumps lose efficiency as the pumping depth increases.
According to the Wisconsin Well Code anyone may install a driven-point well, you do not have to be licensed to install this type of well on your property or anyone else's property. The only restrictions on this ability are that any preliminary excavation or starter drill hole is no deeper than 10 feet and the finished well must meet all requirements in the well code (NR 112) in regard to well location, well construction, pump installation and finishing operations.
A license is not required for a property owner to install a well pump on a driven-point well on his or her own property as long as all requirements of the well code (NR112) are met. But, only a licensed pump installer may install a well pump on someone else's property.
A property owner does not need a license to install a drilled well on his or her own property. Only a licensed well driller can install a drilled well on someone else's property.
- MINIMUM DEPTH: The string of well casing pipe, not including the screen, must
extend to at least the 25-foot depth or to at least 10 feet below the static water level,
whichever is greater. This is the same minimum casing depth as required for private
drilled wells. (The static water level is the normal depth of standing water in the well
before the well is pumped.)
- CASING PIPE: The well casing pipe must be steel or steel-galvanized and must meet
the well code specifications for dimensions and weights and the appropriate ASTM or
API standards. (ASTM A53; A106; A589 or API 5L; 5LX; 5A or 5AX. One of these
standards designation must be either marked on the pipe or available from the supplier.)
- SCREEN: Any standard metal drive-point screen may be used for driven-point wells.
Plastic screens may not be used for driving. The screen does not have to be
continuous-slot. However, screens having a lead content of greater than 8% by weight
also must not be used. Experience has shown a high quality, continuous-slot stainless
steel screened well point will provide efficient trouble-free service for the longest time.
- MINIMUM DIAMETER: There is no minimum diameter for driven-point wells
installed with a shallow-well pump. A shallow-well pump can pull water up from a maximum depth of
only about 20 feet (Figure 2 and Figure 2A).
If you know the pumping water level will be
deeper than about 20 feet then you must use drive pipe having a minimum diameter of at
least 2 inches. This is necessary because the drive pipe must be large enough to
accommodate a packer-jet assembly within the pipe which enables the pump to
pull water up from a greater depth. (See Figure 3 and Figure 3A). Remember, you are not allowed to
construct a pit to get the pump closer to the water table to enable you to use a shallow-well
pump.
- TERMINATION HEIGHT: The wellcasing drive pipe must extend at
least 12-inches above the permanent ground grade. If you plan to landscaping around
the well be sure to leave some extra pipe so the final pipe height is at least 12-inches
above the ground.
- CAP: The top of the drive-pipe must be sealed with a vermin-proof cap such as a
threaded cap that will prevent the entry of insects and mice. Many pumps are directly
connected to the well pipe as, for example, in Figure 4. A sanitary well seal with
compressible gaskets must be used for such installations.
Several types of installations are allowed for the discharge piping from a driven point well:
- ABOVE-GROUND DISCHARGE: With this method the water is discharged through
the top of the well pipe above ground level. The well may be located in:
- An above-ground building or pump house (Figure 4).
- In a walk-out basement of a house. (A walk-out basement is the first floor of a
house built into the side of a hill.) (Wells may not be located in true, non-walkout basements.)
- Outside, unprotected for warm season operation (Figure 5).
- Outside, protected with an insulated structure (Figure 6).
- Outside, protected with an outer protective casing (Figure 7).
- BELOW-GROUND DISCHARGE USING A PITLESS UNIT:
The pitless unit must be Department-approved and must allow for pressurized
concentric piping - the suction pipe within a larger pipe - between the well and the
building.
- The annular space between the concentric piping must be pressurized under water
pressure by installing a "seal-cross fitting" or with a "flange adapter." (Figure 2).
- Installations having non-pressurized concentric piping are not allowed.
- The pitless unit must be installed to a depth necessary to prevent freezing.
- SAMPLING FAUCET: An accessible faucet must be installed on the water line
between the pump and the pressure tank. The faucet must be at least 12-inches above the
floor of the building or basement to allow for filling of sample bottles. The faucet should
have a smooth end or, if threaded, the threads should be filed off. This discourages the
attachment of hoses to the faucet, thus preventing the possibility of back-siphoning of
contaminants into the water system.
- PUMPS: Methods of installation. There are several methods for the installation of
pumps for driven-point wells:
- Direct connection of the pump to the top of the well pipe for both shallow and deep
well pumps. The well can be located in a building or outside for warm seasons.
- Offset connection using horizontal pressurized concentric piping if the well is installed
outside with the pump offset in the basement (Figure 2and 2A and Figure 3 and 3A).
- PUMP TYPES: Two pump types are generally used:
- Shallow-well or shallow-well jet suction pump for water levels less than about 20 feet
deep. (Figure 2 and 2A).
- Deep-well type pump with a packer-jet assembly for water levels deeper than about 20
feet. The minimum well diameter for this type of pump is 2 inches in order to
accommodate the installation of the jet assembly (Figure 3 and 3A). This type of pump can be
used efficiently for wells having pumping water levels down to about 70 to 100 feet.
The well must be located and constructed in compliance with the well code
requirements. Upon completion of the well construction or reconstruction, the installer of
the well must:
- test pump the well, disinfect and flush it
- collect a water sample for bacterial analysis
- submit a well construction report.
A pump installer must:
- install the pitless adapter unit (if used), the pump, the pressure tank and other associated piping and equipment in compliance with the code;
- disinfect the pump distribution system after installation; flush it; take a water sample for bacteriological
analysis and report the results to the owner.
- The pump installer may delegate the water sample collection to the well owner or
another agent.
The well code location requirements for driven point-wells are the same as the
requirements for private drilled wells.
The basic well location requirements are as follows:
- Highest Point on Property
- If reasonably possible, the well must be located on the highest point of the property consistent with the general layout and surroundings and not directly down slope from a contamination source
on the property or on an adjacent property. The well may be side gradient from a
contaminate source provided that surface water that flows over the contaminate source
does not flow within 8 feet of the well. The reason for this requirement is to protect the well from
surface water flow and flooding.
- Basement Location Prohibition
- The well must not be located in a basement, unless it is a walkout basement, i.e. one that is at ground grade on one side of the house. A well located in a basement is subject to contamination from the back-up of sewers and from spills of fuel oil and other products in the basement. Further, terminating a well in a basement effectively reduces the casing depth and thus the sanitary protection provided by the casing. Wells have not been allowed in basements since April 10, 1953.
- Pit Prohibition
- The well must not be located in an unapproved pit. Pits for new wells have been
prohibited without special approval since April 10, 1953. Pits can easily flood and contaminate a well and with the invention of pitless adapters in in the 1930s, pits became unecessary to protect wells from frost.
(A pitless adapter is a piece of equipment that provides a frost-safe underground connection between the well and the pump piping that extends into the basement.)
- Floodplain Locations
- The well must not be installed in a floodway. A floodway is that part of a river valley
floodplain that becomes inundated with the actual flowing floodwater during the regional
100-year flood.
- The well may be installed in a flood fringe of a river floodplain if the top of the casing
pipe is terminated at least two feet above the 100-year regional flood elevation at the well
site. (The flood fringe is that part of the floodplain that may become inundated with
stagnant water during the regional flood.)
- Separation Distance Requirements
- The well must be properly separated from sources of well contamination by the
minimum setback distances as specified by the well code. For example the well must
located be at least:
- 8 feet from a cast iron or acceptable plastic building sewer pipe or 25 feet from building
sewers made of other materials
- 8 feet from a clear water drain (for example: a rain water downspout outlet or
foundation drain discharging to the ground)
- 25 feet from a septic or holding tank
- 25 feet from a lake
- 50 feet from the nearest edge of a soil absorption system or mound system
- 50 feet from municipal sanitary sewers, private collector sewers, or storm sewers
- 50 feet from the nearest existing or future grave site in a cemetery
- 50 feet from animal yards
- one hundred feet from any buried petroleum tank including associated piping, except that only 25
feet of separation is required for a buried fuel oil tank if the tank is used only for private
residential heating
- 250 feet from an absorption, storage, retention or treatment pond, sludge disposal area,
ridge and furrow system, or spray irrigation waste disposal site.
- 1200 feet from any existing, proposed, or abandoned landfill site.
- Note: This list is not complete. Consult Chapter NR 112 the DNR or your local water
well contractor for additional requirements.
The well code defines screen replacement as well reconstruction. A reconstructed well must meet the requirements of the well code at the time it is reconstructed. If the screen on an older driven-point well located in a basement or pit becomes plugged, the screen may not be legally replaced. The well must be properly abandoned and filled and a new well must be constructed in a complying location.
If a driven-point well is contaminated, noncomplying, poses a hazard to health, has not been
used for three or more years, or is in a pit or in a basement, the well must be abandoned by
being properly filled and sealed. A license is not required for an individual nor a firm to do
this work.
Driven-point wells must be filled with cement grout which is a fluid mixture of Portland
cement and water in the ratio of one 94-pound bag of cement to 6 gallons of water or with a
clay-sand slurry having a weight of at least 11 pounds per gallon. The material may be
poured into the top of the well pipe until the well is filled. Any settling within the pipe
must be made up afterwards.
Bentonite clay chips may not be used to abandon driven-point
wells, because they can bridge too easily in the pipe. The drive pipe may be left in place,
but it can be pulled prior to filling of the well if the well is 25 feet deep or less.
A well abandonment form (form 3300-5B or 5W) must be completed and submitted to
your nearest DNR statewide office within 30 days following completion of the abandonment.
The construction of driven-point wells and the installation of pumps for them are
regulated by the Department of Natural Resources. Specific rules are in the Wisconsin Well
Construction and Pump Installation Code (Chapter NR 112). This code, originally passed in
1936, was one of the first well codes in the United States and has been used as a model for rules
in other states. Wisconsin is recognized as a national leader in well protection. A major
code revision (5th Edition) went into effect on February 1, 1991.
The well code is based on the premise that if a well is properly located and
constructed, and if the pumping equipment is properly installed, the well should provide
bacteriologically safe water continuously without need for disinfection treatment.
Several counties have been delegated authority to regulate portions of the well code.
Some of these counties require a Well Location Permit before any well may be installed.
Check with your county before construction.
For additional well code information you may contact the DNR statewide office in your area or your local licensed well driller or pump installer.
If you are in a delegated county, you may contact the County Health or Zoning Department
for more information.
Upon completion of the well and the pump installation the installer is required to:
- Test pump the well to determine the capacity in gallons per minute. For a residence,
the well should produce at least about 4 gallons per minute, but 8 to 10 gpm is better
especially if many water using plumbing fixtures are used in the home. If the well is a
low producer of water, this problem can often be overcome by installing a larger pressure
tank.
- Disinfect the well using a chlorine solution having a chlorine concentration of at least
100 parts per million.
- Flush the well to remove all traces of the chlorine disinfectant.
- Collect a water sample for a bacteriological test; submit the water sample to either the
State Lab of Hygiene or an independent laboratory certified for bacteriological testing
that automatically provides the DNR with a copy of the test results; and provide a report
of the sample results to the owner within 30 days following completion of the analysis.
(The DNR recommends the sample also be tested for nitrate.)
- Submit a report for the well on a well construction report form to the Department of
Natural Resources and provide the owner or his or her agent with a copy of the report
within 30 days of completion of the well.
Local governmental offices such as the Soil Conservation Service or County Zoning Office are
possible sources of information about local conditions. So are neighboring well owners and your local water well contractor. And, the DNR statewide office in your area.
For more information, contact: Margie Damgaard, IS Professional, Public Water Section
Last Modified: Tuesday January 28 2003
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