40A-3.517. Grouting and Sealing

Wells shall be grouted and sealed to protect the water resource from degradation caused by movement of waters along the well annulus either from the surface to the aquifer or between aquifers, and to prevent loss of artesian pressure in artesian aquifers. All wells shall be constructed and sealed using a method which insures that an open or unnaturally permeable annular space does not remain when a well is completed.

(1) Rotary wells located south of grout line. The grout line is established in a Florida Department of Environmental Regulation Grout Exemption Letter, effective 9-10-1980, http://www.flrules.org/Gateway/reference.asp?No=Ref-08941, and is hereby incorporated by reference and can be obtained from the District’s website (nwfwater.com) or from District offices upon request. Wells constructed by the rotary method and located south of the grout line shall have an annular space between the casing and the borehole wall of not less than two inches and shall be sealed according to the following criteria:

(a) All diameter wells constructed by the rotary method and completed into a consolidated formation shall be sealed by filling the annular space with a two-inch thickness of grout from the bottom of the casing to the land surface.

(b) Wells constructed by the rotary method and completed into an unconsolidated formation shall be sealed by filling the annular space with a two-inch thickness of grout from a point above the top of the screen to the land surface if:

1. The well is a public water system as defined in subsection 40A-3.021(39), F.A.C., of this rule;

2. The well is for Limited Use Public Supply use as defined in subsection 40A-3.021(35), F.A.C., of this rule;

3. The well has a diameter of six inches or larger;

4. The well penetrates a confining bed;

5. The well is to be located within one thousand (1,000) feet of any source of pollution, including plants processing hazardous or toxic substances, sanitary landfills (active or closed), sewage percolation ponds, sewage spray irrigation fields, toxic waste disposal systems of any kind including known ground water contamination areas, or other such sources of pollution; or

6. The well, with an approved exemption from the District, is to be located within seventy-five (75) feet of an onsite sewage disposal system (OSDS).

(c) Wells constructed by the rotary method and completed into an unconsolidated formation, but which do not meet the conditions identified in paragraph (1)(b), shall be sealed by filling the annular space with uncontaminated, well-compacted sand and sealing the top of the casing with grout that contains a minimum of one (1) cubic foot of cement.

(2) Rotary wells located north of the grout line. The grout line is established in a Florida Department of Environmental Regulation Grout Exemption Letter, effective 9-10-1980, http://www.flrules.org/Gateway/reference.asp?No=Ref-08941, and is incorporated by reference in subsection 40A-3.517(1), F.A.C., and can be obtained from the District’s website (nwfwater.com) or from District offices upon request. Wells constructed by the rotary method and located north of the grout line shall have an annular space between the casing and the borehole wall of not less than two inches and shall be sealed according to the following criteria:

(a) Wells constructed by the rotary method and completed into a consolidated formation shall be sealed by filling the annular space with a two-inch thickness of grout from the bottom of the casing to the land surface if:

1. The well is a public water system as defined in subsection 40A-3.021(39), F.A.C., of this rule;

2. The well is for Limited Use Public Supply use as defined in subsection 40A-3.021(35), F.A.C., of this rule;

3. The well has a diameter of six (6) inches or larger;

4. The well is to be located within one thousand (1,000) feet of any source of pollution, including plants processing hazardous or toxic substances, sanitary landfills (active or closed), sewage percolation ponds, sewage spray irrigation fields, toxic waste disposal systems of any kind including known ground water contamination areas, or other such sources of pollution; or

5. The well, with an approved exemption from the District, is to be located within seventy-five (75) feet of an onsite sewage disposal system (OSDS).

(b) Wells constructed by the rotary method and completed into a consolidated formation, but which do not meet the conditions identified in paragraph (2)(a), shall be sealed by filling the annular space with a two-inch thickness of grout from the bottom of the casing up to a minimum distance of twenty (20) feet, or into the last confining bed encountered, whichever is greater. The remainder of the annular space shall be filled with uncontaminated, well-compacted sand, clay, or other material that is appropriate for the specific geological conditions encountered and that will prevent degradation of the water resource. The top of the casing shall be sealed with grout that contains a minimum of one (1) cubic foot of cement. Prior approval for the use of alternative methods or materials shall be obtained from the District.

(c) Wells constructed by the rotary method and completed into an unconsolidated formation shall be sealed by filling the annular space with a two-inch thickness of grout from a point above the top of the screen to the land surface if:

1. The well is a public water system as defined in subsection 40A-3.021(39), F.A.C., of this rule;

2. The well is for Limited Use Public Supply use as defined in subsection 40A-3.021(35), F.A.C., of this rule;

3. The well has a diameter of six inches or larger;

4. The well penetrates a confining bed;

5. The well is to be located within one thousand (1,000) feet of any source of pollution, including plants processing hazardous or toxic substances, sanitary landfills (active or closed), sewage percolation ponds, sewage spray irrigation fields, toxic waste disposal systems of any kind including known ground water contamination areas, or other such sources of pollution; or

6. The well, with an approved exemption from the District, is to be located within seventy-five (75) feet of an onsite sewage disposal system (OSDS).

(d) Wells constructed by the rotary method and completed into an unconsolidated formation, but which do not meet the conditions identified in paragraph (2)(c), shall be sealed by filling the annular space with uncontaminated, well-compacted sand and sealing the top of the casing with grout that contains a minimum of one (1) cubic foot of cement.

(3) Driven wells located north or south of the grout line. Wells with casing which is driven starting at the land surface and thence to its final depth in a borehole that is equal to or smaller in diameter than the outside diameter of the casing, or which is driven starting at the land surface and thence to its final depth ahead of the drill bit, shall be sealed with grout if:

(a) Any part of the well is constructed by setting the casing in a previously constructed borehole which is larger in diameter than the outside diameter of the final casing, or, for any other reason, a space is created between the borehole and the casing. Such a well shall be sealed by filling the annular space with grout from bottom to top.

(b) The well is a public water system as defined in subsection 40A-3.021(39), F.A.C., of this rule or is for Limited Use Public Supply use as defined in subsection 40A-3.021(35), F.A.C., and the well is constructed by driving casing into a consolidated formation. Such a well shall be sealed by under-cutting or under-reaming the last five (5) feet of the hole before seating the casing. A minimum of one (1) foot of the enlarged hole must be in the consolidated formation in which the casing will be seated. The entire enlarged portion of the hole shall be filled with grout and the casing driven through the grout to refusal. The upper twenty (20) feet of the well shall have an annulus not less than two inches, and shall be sealed by filling the annular space with grout.

(4) Grouting and sealing of water wells shall be accomplished in the following manner unless an exemption is granted by the District for the use of alternative methods or materials that are appropriate for the specific geological conditions encountered and that prevent degradation of the water resource.

(a) Composition of neat cement grout shall not exceed six (6) gallons of water per cubic foot or 94-pound sack of Portland cement.

(b) The casing shall be centered in the borehole prior to grouting and sealing.

(c) In all cases, neat cement grout will be introduced into the annular space from bottom to top.

(d) The minimum set time for grouting of casing before drilling operations may continue will be as specified in Table 3 below.

TABLE 3

GROUT SETTING REQUIREMENTS

 

TYPE OF WELL	STEEL CASING	PVC CASING
Public Supply Well	MINIMUM OF 72 HOURS	MINIMUM OF 72 HOURS
Limited Use Public Supply	MINIMUM OF 12 HOURS	MINIMUM OF 12 HOURS
Well
Other Wells:
4 Inches and	Driven into a consolidated	Constructed into a
Smaller in	formation with drive shoe	consolidated formation
Diameter	MINIMUM OF 2 HOURS	utilizing a shell packer
		MINIMUM OF 4 HOURS
	Not driven into a	Constructed into a
	consolidated formation	consolidated formation
	but utilizing a shell	not utilizing
	packer	a shell packer
	MINIMUM OF 4 HOURS	MINIMUM OF 12 HOURS
	Sand-and-gravel wells	Sand-and-gravel
	which penetrate a confining	wells which penetrate
	bed which do not	a confining
	utilize a shell packer	bed and which do not
	MINIMUM OF 12 HOURS	utilize a shell
		packer
		MINIMUM OF 12 HOURS
Larger than 4
Inches in
Diameter	MINIMUM OF 12 HOURS	MINIMUM OF 12 HOURS

(5) Other approved methods and materials may be used if they are appropriate for the specific geological conditions encountered and if they prevent degradation of the water resource. Prior approval for the use of alternative methods or materials shall be obtained from the District.

(6) In those cases where, during grouting operations, circulation of the neat cement grout is lost so that the annular space being grouted cannot be filled in one continuous operation, a tremie pipe shall be installed in the annular space to a point immediately above the zone of lost circulation; and the annulus shall be bridged at that point by sand or other suitable material introduced through the pipe until a level is reached at which grouting can be continued.

Rulemaking Authority 373.044, 373.113, 373.171, 373.309, 373.337 FS. Law Implemented 373.306, 373.308, 373.309 FS. History–New 1-9-86, Formerly 40A-3.701(2)(e), Amended 8-10-87, 4-5-88, 8-1-89, 12-1-90, 11-1-92, 11-1-93, 8-15-18.