A.
In establishing the location to a water well, the installer
shall give consideration to sources of contamination which exist on or adjacent
to the site. All water supply wells shall be located an adequate horizontal
distance from potential sources of contamination and pollution.
B.
Variable geologic and hydrologic conditions make it impossible
to establish regulations to suit all conditions. The following minimum lateral
distances shall apply to common sources of contamination listed:
|
Sources of Contamination
|
Minimum Lateral Distances
(feet)
| |
|---|---|---|
|
Subsurface disposal facilities
|
100
| |
|
Cesspools, seepage pits
|
100
| |
|
Septic tank, dosing tank
|
100
| |
|
Sewers (watertight joints) footing drains
|
25
|
C.
A water well shall also be a minimum of 50 feet from
the property line except that it may be 25 feet from a public way.
D.
Where, in the opinion of the Board of Health, adverse
conditions exist, the above distances may be increased. In certain cases,
special means of protection may be provided. Where possible, the well shall
be up the groundwater gradient (upstream) from sources of contamination. The
top of a well shall be above ground that is higher than any surface sources
of contamination and above any known conditions of flooding by drainage of
runoff from the surrounding land, unless located in a floodproof house.
A.
Casing material. Well casing shall be sufficiently strong
to perform the functions for which it is designed, i.e., to maintain the hole
by preventing wall collapse, to provide a conduit for water conveyance and
to maintain the quality of water pumped. Permanent wells shall be cased with
not less than schedule 40 steel, or not less than schedule 40 PVC plastic,
concrete or other durable pipe material. The thickness of casing shall be
selected in accordance with good design practice as applied to conditions
encountered in the area where the well is located.
B.
A well casing or extension thereof shall extend vertically
for at least six inches above established ground surface or above the floor
of an approved pump pit. The Board of Health or its agent may approve in writing
a casing termination two inches or greater above the established ground surface
in paved areas if the area is not subject to flooding or contamination and
the connections and openings are threaded or welded watertight.
C.
All casing shall be placed with sufficient care to avoid
damage to casing sections and joints. All casing joints above perforations
or screens shall be watertight.
D.
Water well pipe salvaged from water test holes or nonproductive
holes may be used as new pipe if in good condition. Pipe intended for water
well use is subject to random examination by the regulating agency which shall
reject defective pipe. Pipe that is considered defective includes but is not
limited to:
The annular space between the protective well casing and the wall of
the drilled hole or the surface casing shall be effectively sealed to protect
against contamination or pollution by surface and/or shallow subsurface waters.
This shall be accomplished in accordance with guidelines set forth below:
A.
Depth of seal.
(1)
Following is the minimum depth of seal below ground surface
for various uses of wells:
|
Type
|
Depth of Surface Seal
(feet)
| |
|---|---|---|
|
Local water supply wells
|
20
| |
|
Domestic wells
|
6
|
(2)
Exceptions are shallow wells where the water is at a
depth less than 20 feet. In this instance, the depth of seal may be reduced,
and special precautions shall be taken in locating the well with respect to
possible sources of contamination.
(3)
The annular space shall be sealed to a minimum depth of 20 feet from the surface of the ground when the well is close to individual domestic wells or to sources of contamination or pollution described in § 480-8. Local conditions, such as the existence of shallow subsurface waters of undesirable quality, may warrant consideration of sealing the annular space around agricultural wells.
B.
Sealing conditions. Following are requirements for sealing
the protective casing of a well:
(1)
(2)
Wells that penetrate impervious formations. If a consolidated formation or an impervious unconsolidated formation is encountered within five feet of the specified depth of seal described in Subsection A of this section, the seal should extend at least five feet into the impervious formation.
(3)
Gravel-packed wells. The gravel pack of gravel-packed
wells shall terminate at the base of the protective seal.
(4)
Wells penetrating consolidated rock. A hole of sufficient
diameter to accommodate protective casing must be constructed and the annular
space between the rock and casing sealed to depth specified in this section:
(a)
Sealing material.
[1]
The sealing material shall consist of neat cement, cement
grout, puddled clay or concrete. Organic polymer muds shall not be allowed.
The neat cement mixture shall be composed of one bag of Portland Cement (94
pounds) to five to seven gallons of clean water. Quick setting cement, retardants
to setting and other additives, including hydrated lime to make the mix more
fluid (up to 10% of the volume of the cement) and Bentonite (up to 5%) to
make the mix more fluid and to reduce shrinkage, may be used. Concrete used
shall be Class B (six sacks to the cubic yard) or Class B (five sacks to the
cubic yard).
[2]
Clay in the form of a mud-laden fluid is similar to and
has the advantage of neat cement and cement grout. There is a disadvantage
in that clay may separate out of the fluid. A Bentonite-gelatenous mud is
recommended. Concrete is useful in sealing large diameter wells, particularly
where the width of annular ring is several inches or more. However, unless
care is exercised during placement, the coarse aggregate may become separated
from the cement.
(b)
Thickness of seal. The thickness of the seal shall be
at least one inch, and not less than three times the size of the largest coarse
aggregate used in the sealing material.
(c)
Placement of seal. The sealing material shall be installed
in one continuous operation from the bottom of the interval to be sealed to
the top.
(d)
Sealing casing into bedrock. For all wells which terminate
in bedrock, a permanent casing shall extend from six inches above the ground
or floor of a pit into bedrock a minimum of 10 feet below the bedrock surface.
A well installed in an unconsolidated sand and gravel aquifer commonly
has a screen. Screen openings shall be properly sized, based on sieve analysis
of material at the screen depth. The well shall be properly developed to produce
sand-free water at the pumping rate of the permanent pump.
Where a well penetrates aquifers separated by confining layers and any
of the aquifers contain water that would be a contaminant, contaminated strata
shall be sealed to prevent entrance of the water into the well or its migration
to other aquifer(s).
A.
The contaminated stratum shall be sealed by placing impermeable
material in the annular space between the protective casing and the contaminated
stratum. The seal shall extend into the upper and lower confining formations
for a sufficient vertical distance to prevent the vertical movement of water
from the producing formation. Sufficient sealing material shall be installed
to fill the annular space between the casing and the wall in the drilled hole
along the sealed interval and to fill the voids which might absorb sealing
material. Sealing material shall be placed from the bottom to the top of the
sealed interval.
B.
Sealing material shall consist of neat cement, cement grout or other suitable impermeable material. See § 480-10B(4)(a).
All local water supply, domestic and industrial wells shall be disinfected
following construction, rehabilitation and well pump repair before the well
is placed in service. The well shall be pumped to waste until the water is
as clear as possible. Thereafter the well and pumping equipment shall be disinfected
with a solution containing at least 50 parts per million of chlorine. The
well shall remain in contact with chlorine solution a minimum of 24 hours
before the well is pumped to waste and chlorine flushed from the distribution
system. All water used in well drilling shall be disinfected.
A.
Openings. Openings into the top of the well which are
not to provide access shall be sealed. All access openings into the well shall
be protected against entrance of surface water.
(1)
Where the pump is installed on top of the well, a watertight
seal shall be placed between the pump head and the pump base (slab).
(2)
Where the pump is offset from the well or well is equipped
with a submersible pump, the opening between the protective casing and any
distribution pipes or support or electrical cables which enter the well shall
have a watertight seal.
(3)
All holes into the pump that are open to the well shall
be sealed.
(4)
All wells equipped with a pump shall have a watertight
cap at all times.
(5)
All below-ground discharge pipes shall have a watertight
seal or gasket between the discharge pipe and well casing.
(6)
Any concrete base or slab (sometimes called a "pump block"
or "pump pedestal") constructed around the top of a casing shall be watertight
and free from cracks for at least six inches above the pump chamber floor.
B.
Pump blowoff. Any pump discharge blowoff or drain line
shall be located so as to not be affected by flooding, backsiphonage or back
pressure, and shall not be connected to a sewer.
A.
All well development and rehabilitation shall be done
with care and by methods that will not cause damage to the well, degrade groundwater
quality or alter subsurface conditions to allow vertical movement of contaminated
water between aquifers. The following methods used in developing or conditioning
a well, when done with care, are acceptable:
B.
Methods which produce an explosion are not prohibited,
however, they should be used with care, particularly where two or more distinct
aquifers have been penetrated. Where chemicals or explosives have been used,
the well shall be pumped until all trace of these agents has been removed.
A.
The well driller (installer) shall collect samples in
the presence of a representative of the Board of Health.
B.
Water quality sampling shall be conducted in accordance
with the following requirements:
(1)
Local, domestic and potable water supply wells. The water
from local, domestic, industrial and commercial potable water supply wells
shall be sampled immediately following development and disinfection. Chemical
and bacteriological analyses shall be made, and approval of the Board of Health
must be obtained before the well is used.
(a)
Sample tap. A representative sample for laboratory analysis
shall be collected at pump discharge or from a tap in the pump discharge line.
(b)
Laboratory analyses. Required water analyses shall be
performed by a laboratory certified by the Massachusetts Department of Environmental
Quality Engineering. A copy of the laboratory analysis results shall be forwarded
to the local Board of Health and the well owner.
(c)
Bacterial quality. Water samples for bacteriological
analysis (presence of coliform organism) shall be collected from domestic
water supplies after development and after all traces of disinfectant chemicals
have been removed from the well. The results of the bacteriological analysis
shall meet the standards specified in 310 CMR 22.00 (Massachusetts Drinking
Water Regulations).
(d)
Chemical (mineral) quality.
[1]
All groundwater produced where the water is to be used
for consumption or for food processing shall be analyzed for its chemical
content. The results of the chemical analyses shall meet the following standards:
|
Chemical or Mineral
|
Standard to be Met
(milligrams per liter)
| |
|---|---|---|
|
Chlorides
|
<125
| |
|
Hardness
|
<250
| |
|
Manganese1
|
<0.05
| |
|
Iron1
|
<0.3
| |
|
Sodium2
|
<20
| |
|
Nitrate-nitrogen
|
<10
|
|
NOTES:
| |
|
1 Failure to meet these standards shall require
treatment.
| |
|
2 This standard is included to inform the
prospective homeowners that failure does not constitute disapproval of the
well.
|
[2]
It is suggested that the nitrate-nitrogen test be performed
annually.
(2)
The Board of Health may require additional tests as local
conditions warrant if in its opinion they are necessary to protect the public
health and welfare.
A.
All wells yielding more than 50 gallons per minute shall
be tested to determine yield and water level recovery. All test records and
analysis of safe yield shall be submitted to the Board of Health. Test pumping
shall be conducted at a rate at least equal to the pumping rate expected during
normal use (usually five gallons per minute for domestic wells). The pump
test shall be conducted for a period of four hours and repeated after a shutdown
of 24 hours.
B.
The pumping test shall be performed by a licensed pump
or well installer.
A well shall be plumb to allow proper installation and pump operation.
A.
Bored wells. All bored wells shall be cased with concrete pipe or steel casing whose joints are watertight from six inches above surface to the depth specified in § 480-10A. The space between the wall of the hole and the casing shall be filled with concrete to the depth specified in § 480-10A. The minimum thickness of the surrounding concrete seal shall be three inches.
B.
Dug wells. All dug wells shall be curbed with a watertight curbing extending from a minimum of six inches above the ground surface to the depth specified in § 480-10A. The curbing shall be of concrete poured in place or casing (either precast concrete pipe or steel) surrounded on the outside by concrete. If the curbing is to be made of concrete, poured-in-place, it shall not be less than six inches thick. If precast concrete pipe or steel casing is used as part of the curbing, the space between the wall of the hole and the casing shall be filled with concrete to the depths specified in § 480-10A. The minimum thickness of the surrounding concrete shall be four inches.
C.
Casing material. Either steel or concrete may be used
for casing bored or dug wells.
(1)
Steel used in the manufacture of casing for bored or dug wells should conform to the specifications for casing material described in § 480-9 (schedule 40 steel or schedule 40 PVC plastic). Minimum thickness of steel casing for dug wells shall be one-fourth-inch United States standard gage (for plate thickness) for wells of diameter 18 through 48 inches.
(2)
Concrete casing may consist of either poured-in-place or precast concrete pipe. Poured-in-place concrete shall be sufficiently strong to withstand the earth and water pressure imposed on it. It shall be properly reinforced with steel to furnish tensile strength and to resist cracking and it shall be free from honeycombing or other defects likely to impair the ability of the concrete structure to remain watertight. Aggregate small enough to ensure proper placement without bridging shall be used. Only air-entraining cement shall be used in water well construction. Precast concrete pipe is usually composed of concrete rings from one to six feet in diameter and approximately three to eight feet long. To serve satisfactorily as casing, these rings shall be free of any blemishes that would impair their strength or serviceability. In the portion of the well that is to be sealed (see Subsections B and C of this section) the joints shall be made watertight using a cement-based (not brick mortar) material.
D.
Covers. All bored and dug wells shall be provided with
a structurally sound cover to prevent injury to people or animals and to prevent
the entrance of undesirable water or foreign matter.
Whenever there is an interruption in work on the well such as overnight
shutdown, inclement weather, waiting periods for the setting up of sealing
materials or concrete, tests, installation of the pump, etc., the well opening
shall be closed with a cover to ensure the public safety. During interruptions
of one week or more, a semipermanent cover shall be installed. For a well
cased with steel, a steel cover, tack-welded to the top of the casing, is
adequate.
Water used for cooling parts of engines, air compressors or other equipment
or water used for air conditioning shall not be returned to any part of a
potable water system or potable aquifer unless the water was obtained from
the same aquifer into which it is being discharged and the discharge water
is of equal or better mineralogical and bacteriological quality as the source.
All deepening or repair of wells shall meet all the requirements included
in these regulations and shall be done with a permit.
Installation of a water storage reservoir, but not an approved water
pressure tank, requires approval of and a permit from the Board of Health
or its agent.
An owner or occupant using a polluted water supply or a supply that
represents a health hazard shall be notified of the health hazard, in writing,
by the Board of Health or its agent (MGL C. 111, § 122A).
Permission may be granted by the Board of Health or its agent to use
springs, infiltration tile lines or other sources as a water supply or to
install water treatment facilities. Plans and specifications for such facilities,
together with operating procedures, shall be approved by the Board of Health.
A physical connection is not permitted between a water supply meeting the
requirements of these regulations and another water supply that does not meet
such requirements without prior approval of the Board of Health.
