1. Casing.
A. All wells serving as a water supply shall be equipped with a watertight and durable wrought iron, steel, or other type of approved well casing having a minimum thickness of 0.1875 inches or PVC plastic casing having a minimum thickness of 0.175 inches. The sections of casing shall be joined together by threaded couplings or joints, by welding, or by any other watertight approved joint or coupling. The casing shall be carried to a minimum depth of 20 feet and (then) extended an additional 5 feet into firm bedrock or other impervious strata, firmly seated in competent formation with a drive shoe and grouted in place. Well casing material other than wrought iron or steel must be resistant to the corrosiveness of the water and to the stresses to which it will be subjected during installation, and the grouting operation. Casing and grouting materials must be compatible. The criteria established in AWWA Standard Al 00-84 must be followed. Casings shall terminate a minimum of 1 foot above the surrounding, finished surface grade and shall not be cut shorter. All casings for water supply or geothermal return wells shall be fitted with a water-tight or sanitary seal well cap.
B. Ferrous casings shall be new pipe meeting ASTM or API specifications for water well construction, have additional thickness and weight if minimum thickness is not considered sufficient to assure reasonable life expectancy of the well, be capable of withstanding forces to which it is subjected, and have full circumference welds or threaded pipe joints.
C. Non-ferrous casings shall meet appropriate ANSI/ASTM or NSF Standards for well casing applications as outlined in A WW A Standard Al 00-84. Non-ferrous casing materials shall not impart any taste, odor, or toxic substances to the well water. Non-ferrous casing, if used, shall not be driven. The casing shall be placed a minimum of 5 feet into the consolidated formation with a niinimum annular opening of 3 inches or larger so that the grout may be placed in accordance with the provisions of § 23-402.2.
D. Whenever maintenance such as pump, drop pipe, foot valve, or electrical wiring repair or replacement is done to an existing well where the casing terminates at or below the surrounding surface grade, the casing shall be extended so that it meets the requirement of § 23-402.1.A, in that the casing shall extend to a minimum of 1 foot above the surrounding finished surface grade. This shall apply to all casings that currently terminate in well pits. These casings shall be extended above the surrounding ground surface and the pit shall be eliminated.
E. Casings of existing wells that terminate below the surrounding finished grade may be extended by: welding steel extensions to existing casings where practicable; glued PVC coupling joints; or any other method specifically approved by this Borough.
F. In all cases where a casing is extended, a pitless adapter and a sanitary seal well cap must be installed.
2. Grout Materials and Placement.
A. All grout information (type of cement or bentonite and number of bags of cement or bentonite used for grouting) must be submitted in writing on well construction form (Form 23-2) to the Borough by the well driller within 30 days of completion of the well drilling process.
B. In all well installations an annular space shall be provided between the well casing and the earth formation. The annular space shall be completely filled with approved grout materials, in one continuous operation, under pressure from the bottom to the natural land surface, within 24 hours after completion of the drilling. In the event that grouting is done following the completion of all drilling operations, care must be taken to prevent the entrance of driller’s mud into the annulus during the completion of the borehole by the use of a
rubber packer or other acceptable method. The annular space shall be completely cleared of all obstructions prior to the placement of the grout material. Exterior grouting methods must be used in this instance. The casing shall be sealed effectively against entrance of water from water bearing zones that are subject to pollution, through which the casing may pass, by grouting a minimum of 10 feet above and 10 feet below the polluted or undesirable water-bearing zone. During the installation of the pitless adapter, grout material may be removed from the exterior of the casing in order to provide a watertight seal between the casing and the pitless adapter.
C. After the grout has been placed in the annular space, drilling of the borehole may proceed for a maximum of 4 hours, and if not completed within that time period, a curing time of 36 hours must be provided before drilling can resume. A curing time of 12 hours for Type III Portland cement must be provided immediately following the placement of the grout. Drilling is not permitted during the curing period. If casings of smaller diameter are used in the lower portions of the well, effective watertight seals shall be provided between the casings where they telescope for a minimum distance of 4 feet.
D. The annular space of all well installations must be filled with one of the following listed grout materials.
(1) Neat cement grout shall consist of a mixture of API Class G (or Class B similar to ASTM CI50 Type II) and water in the ratio of 0.67 cu. ft. of water per 94 lb. sack weighing approximately 228 lbs/cu ft3. A maximum of 6% by weight bentonite and 2% by weight of calcium chloride may be added.
(2) Pozmix-cement grout shall consist of a mixture of 50% by volume of Pozzolan A (74 lbs./cu. ft3) and 50% by volume of API Spec. 10, Class G cement with 0.77 cu. ft. of water per 84 lbs. of mixture. To this mixture may be added a maximum of 2% by weight, bentonite and a maximum of 2% by weight of calcium chloride, at the discretion of the contractor.
(3) Concrete grout shall contain 5.3 sacks of portland cement (ASTM C150 Type II) per cubic yard of concrete and a maximum of 7 gal. of water per 94 lb. sack of cement. The maximum slump shall be 4 in. the aggregate shall consist of 47% sand and 53% coarse aggregate, conforming to ASTM Designation C-33. The maximum size aggregate should be 0.75 in. Concrete grout shall not be placed in an annulus of less than 3 in.
(4) Sand cement grout shall consist of a mixture of portland cement (ASTM CI 50 Type II), sand and water in the proportion of not more than two parts by weight of sand to one part of cement with not more than 6 gal. of water per 94 lb. sack of cement.
(5) Bentonite grout shall be a pure bentonite with at least 20% solids by weight when mixed with water. Hydration of the bentonite must be delayed until the bentonite mix has been placed down the well. This can be done by using additives with the dry bentonite or in water; mixing calcium bentonite with sodium bentonite; or by using granular bentonite, which has less surface area.
E. In all well installations if rapid loss of grout material occurs during placement, coarse fill material (e.g. sand, gravel, crushed stone, dry cement) may be used in the zone or zones in which the rapid loss is occurring. The remainder of the annular space shall be grouted as provided below. In no case shall pouring, dumping or shoveling of grout material into the annular space be deemed an approved method of grout placement.
3. Grout Placement.
A. Grout Pipe Outside Casing.
(1) The minimum annular space of VA inches around the entire outside of the casing shall be provided by drilling a borehole 3 inches larger than the outside diameter of the casing to be inserted. All grout shall be placed by pumping through the grout pipe. The entire interval to be grouted shall be open and without obstructions. Washing or jetting with water is recommended for cleaning the borehole and may serve to remove obstructions caused by caving which otherwise would prevent a proper grout. It is recommended that the grout pipe extend from the surface to the bottom of the interval to be grouted. The grout pipe may remain extended to the bottom of the interval during and after grouting, or it may be raised slowly as the grout is placed provided that the discharge end of the grout pipe remains submerged in the emplaced grout at all times until grouting is completed. In the event of interruption in the grouting operations, the bottom of the grout pipe shall be raised above the grout level and should not be re-submerged until the air and water have been displaced from the grout pipe.
(2) Grouting Depths Greater than 30 feet. The minimum length of grout pipe that shall be inserted into the annular space is 30 feet.
(3) Grouting Depths of 30 feet and less. Grout may be placed by a tremie pipe inserted only a short distance (approximately 5 feet) into the annular space provided that the entire interval to be grouted is clearly visible from the surface and is dry. An annular space larger than the minimum 1½ inches may be required to assure visibility from the surface.
B. Grout Pipe Inside Casing. The bottom of the casing is fitted with a packer arrangement, also referred to as a cementing shoe or float shoe, and the casing is placed in the borehole a short distance off the bottom. The float shoe allows grout to be pumped through the grout pipe and upward into the annular space, while preventing grout leakage into the casing during grouting and after removal of the grout pipe. Grouting is continued until cement appears at the surface at which time the grout pipe is disconnected from the float shoe. The float shoe is drilled out after the grout sets and hardens sufficiently.
C. Interior Method Two Plug. The first plug separates the grout from the fluid in the casing, and the other separates the grout from water pumped in above it. First, the casing is placed a short distance off the bottom. After pumping water through the casing to circulate fluid in the annular space and clear any obstructions from the hole, the first plug is inserted, and the casing is capped. A measured volume of grout is pumped in, which is sufficient to fill the annular space. The casing then is opened, and the second plug inserted. A measured volume of water is pumped in above the second plug until it is pushed to the bottom of the casing and most of the grout is expelled up and into the annular space. The water in the casing is held under pressure to prevent the backflow of grout until it has set and hardened.
D. Interior Method Upper Plug. The casing is placed a short distance off the bottom, and the water is pumped into the casing to circulate fluid through the annular space to clear any obstructions from the hole. A measured quantity of grout slightly greater than that needed to fill the annular space is pumped into the capped casing. Because this grout is in direct contact with the drilling fluid, there will be a narrow zone of weak grout between the drilling fluid and good grout; however, this zone should remain inside the casing and not be forced into the annular space. The casing is opened, and a drillable plug is inserted. A measured volume of water is pumped in above the plug until it is pushed to the bottom of the casing and most of the grout is expelled up and into the annular space. The water in the casing is held under pressure until the grout sets and hardens.
E. Interior Method Capped Casing. The casing is placed a short distance off the bottom, and water is pumped into the casing to circulate fluid in the annular space and clear any obstructions from the hole. The grout pipe passes through an airtight cap at the top of the casing and is positioned 3 to 4 feet above the bottom of the casing. The grout pipe is assembled so that it can be pulled through the cap a distance of about 20 feet after the injection of grout is completed. A bleeder valve is provided to release air from inside the casing as it is filled with water. The first step is to fill the casing and annular space with water. With the upper end of the casing closed, grouting is started by forcing the cement through the grout pipe upward into the annular space.
Grouting is continued until the cement overflows around the casing at ground surface. Just enough water is pumped to clear the cement from the grout pipe, and the grout pipe is lifted free of the grout. Both the casing and grout pipe shall be kept tightly closed under pressure until the cement sets and hardens.
F. Grout Displacement Method. The hole is filled with the estimated volume of grout required to fill the annular space, and the casing is lowered into the hole. The bottom of the casing is closed in a tight, drillable plug. Guides often are used to keep the casing centered in the hole. As the casing is lowered, the grout is forced upward around it to fill the annular space. If the pipe does not sink to the bottom under its own weight, it is filled with water.
G. Unconsolidated Formations. When drilling through an unconsolidated formation, a steel drive shoe shall be required. Grouting shall be done in accordance with the following:
(1) If caving conditions are experienced on wells deeper than 30 feet, the annular space shall be grouted from the point where caving occurred or from a depth of 30 feet, whichever is greater, to land surface.
(2) If the annular space cannot be grouted in accordance with this Chapter, the well shall be decommissioned and sealed in accordance with Part 7 of this Chapter.
H. Other grouting methods and materials may be used subject to prior written approval of the Borough.
4. Packers. Packers, when used, shall be of materials that will not impart taste, odor, toxic substances or bacterial contamination to the well water.
5. Well screens. Well screens, when used, shall:
A. Provide the maximum amount of open area while still maintaining structural strength;
B. Have the size of openings in the screen based on a sieve analysis of the material contained in the surrounding geological formation or gravel pack;
C. Be constructed of materials resistant to damage by chemical action of groundwater or cleaning operations;
D. Have sufficient diameter to provide adequate specific capacity and low aperture velocity. Usually, the entrance velocity should not exceed 0.1 feet per second;
E. Be installed so that the pumping water level remains above the screen under all operating conditions;
F. Be designed and installed to permit removal or replacement without adversely affecting water-tight construction of the well; and
G. Be provided with a bottom plate or washdown bottom fitting of the same material as the screen.
6. Gravel packs. Gravel packs when used:
A. Shall be well rounded particles, 95% siliceous material, that are smooth and uniform, free of foreign material, properly sized, washed and disinfected immediately prior to or during placement;
B. Shall be placed in one uniform continuous operation;
C. Gravel refill pipes, when used, shall be Schedule 40 steel pipe incorporated within the pump foundation and terminated with screwed or welded caps at least 12 inches above the pump house floor or concrete apron;
D. Gravel refill pipes located in the grouted annular opening shall be surrounded by a minimum of 1½ inches of grout; and
E. Protection from leakage of grout into the gravel pack or screen shall be provided.
7. Pit Installations. Pit installations for new well construction will only be allowed when specifically approved by the Borough. Pit installations are where the casing terminates in an open space, constructed below the ground surface. If the installation of a well pit is permitted it shall comply with the following requirements:
A. Well pits shall be maintained free of water at all times.
B. The floor of the pit shall be a watertight reinforced concrete platform at least 4 inches thick poured around the casing and shall be provided with a watertight seal. The floor of the pit shall extend at least 2 feet from the center of the casing in all directions. In all cases, the pit shall be sized to allow adequate working space. The casing shall extend above the floor for at least 12 inches. An insect resistant well cap shall be installed. The surface of the floor shall be pitched toward a drain that has a minimum diameter of 4 inches and discharged by gravity to the surface of the ground in an area not subject to flooding or to a basement that is effectively protected against flooding.
C. Drain openings shall be effectively screened to prevent the entrance of insects and rodents. The drain shall not be connected to any sewer or other drain.
D. The pit shall have watertight reinforced concrete walls 4 inches thick or equivalent, which provide for an effective watertight seal against the floor. The top of the pit shall be a watertight reinforced monolithic concrete slab at least 4 inches thick, which shall be sealed with the wall so as to effectively prevent the entrance of water.
E. The top of the pit shall not be more than 6 inches below the ground surface. A durable watertight manhole shall be installed in the top of the pit centered over the casing and effectively sealed with the top to prevent the entrance of water. This manhole shall be at least 24 inches in diameter. It shall extend at least 3 inches above the surrounding ground surface and be covered by an impervious durable cover of concrete, steel, or equivalent material that overlaps the manhole vertically by at least 2 inches. The manhole cover shall be effectively secured to the manhole by bolting, locking or equivalent means, and shall be kept secured.
F. Pit installations shall not be used in areas subject to flooding by ground or surface water or where the groundwater level rises to within 1 foot of the bottom of the proposed pit. When pipes enter the pit, the annular space between the pipes and the wall shall be effectively sealed by a watertight permanent seal.
8. Pitless Installations. Pitless installations are those installations where the casing terminates above the ground or surrounding finished grade surface.
A. Where pitless installations are used, they shall be of a design that provides an effective seal against the entrance of ground or surface water into the well, access casing, and into the piping leading to the pump. All buried suction lines shall be effectively encased, or otherwise protected to prevent external damage or contamination. Pitless installations must be so designed as to be structurally sound and to provide for ready removal of drop piping without excavation. Pitless adapters shall be installed at a minimum depth of 30 inches so that it will be safely below the frost line, but no deeper than 48 inches. The access casing shall be effectively protected against corrosion and shall extend at least 12 inches above the natural ground or surrounding finished grade surface. The ground level or surrounding finished grade surface at this point shall be elevated above the adjacent ground level and graded to drain away in all directions. The top of the access shall be effectively sealed against the entrance of water, insects, and rodents. An insect resistant cap shall be installed. The pitless adapter shall not be submerged in water or used in areas used by automobiles and other vehicles.
B. Where surface installations (i.e., pump rooms, etc.) are used, a watertight reinforced concrete platform at least 4 inches thick and extending for at least 2 feet in all directions from the center of the casing shall be poured around the casing to provide an effective watertight seal with the casing, or shall be made watertight with an effective permanent seal. The surface of the platform shall slope to the edges. The casing shall extend above the slab at least 12 inches and shall be effectively sealed against the entrance of contamination. An insect resistant well cap shall be installed where appropriate. All pumping equipment shall be protected against freezing. If a pump room is proposed, it shall be so sized to allow adequate working space.
9. Venting. Where venting is required, an overlapping cover or pipe with the opening facing downward shall be required. Such venting shall be effectively protected against the entrance of insects and rodents. An insect resistant well cap shall be installed. In no case shall openings be less than 12 inches from the ground, or, in the case of pit installations, the floor.
10. Private Water Supply System Standard.
A. A private water supply system shall produce at least 480 gallons of water in a 2-hour period (4 gpm), at least once each day for each separate residence, facility or use. Greater yields maybe required depending on the intended use.
B. If the sustained yield of the private well or water system is not capable of meeting the total private water supply system standard, sufficient storage shall be required. Borehole capacity and/or a storage tank shall provide storage capacity.
11. Minimum Yield for Private Wells.
A. All potable water supply wells intended to serve as a private water supply shall be approved for yield in accordance with this section. Replacement wells servicing existing improved properties may be exempt from this requirement at the discretion of the Borough Engineer.
B. The criteria for approval shall be a minimum well yield of 1 gallon per minute.
C. For wells with yields of 2 gallons per minute or less, a minimum of 400 gallons of storage capacity shall be provided. Borehole storage shall be measured from the pump level to the top of the static water column. Wells with yields between 2 and 4 gallons per minute shall provide the storage capacity required to meet the individual water supply standard described in § 23-402.10.
D. The minimum well yield requirements set forth in this section are deemed sufficient to supply an adequate quantity of water for normal indoor household or equivalent usage. A supplemental source of water may be needed to support outdoor or other non-consumptive uses.
(Ord. 613, 5/11/2015)