La. Admin. Code tit. 51 § XII-169

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Current through Register Vol. 50, No. 11, November 20, 2024

Section XII-169 - Groundwater

A. A groundwater source includes all water obtained from:

1. dug;

2. drilled;

3. bored or driven wells;

4. springs; and

5. infiltration lines.

B. Groundwater quantity shall conform to the following standards.

1. Source capacity. The total developed groundwater source capacity, unless otherwise specified by the state health officer, shall equal or exceed the design maximum day demand with the largest producing well out of service.

2. Number of sources. When groundwater is the only source of water supply for any community water supply or for any non-community water supply serving a hospital, a minimum of two approved and active groundwater wells (or, if not a second well, connection to another approved water supply of sufficient capacity) shall be provided, unless otherwise specified by the state health officer.

a. Each of these two groundwater wells (or, if not a second well, connection to another approved water supply of sufficient capacity) shall be maintained and regularly operated to ensure that each one can immediately supply safe drinking water into the system when the other fails.

b. Consideration should be given to locating redundant sources in different aquifers or different locations of an aquifer.

3. Standby power. To ensure continuous service provided by any community water supply and any non-community water supply serving a hospital when the primary power has been interrupted, a standby power supply shall be provided through a dedicated portable or in-place auxiliary power of adequate supply and connectivity. When automatic pre-lubrication of pump bearings is necessary, and an auxiliary power supply is provided, design shall assure that the pre-lubrication is provided when auxiliary power is in use.

C. Groundwater Quality shall conform to the following standards.

1. An assessment should be made of the factors, both natural and man-made, which may affect water quality in the well and aquifer. Such an assessment may include, obtaining samples over a sufficient period of time to assess the microbiological and physical characteristics of the water including dissolved gases, chemical, and radiological characteristics.

2. Unless LDH-OPHs exclusion criteria are met, a ground water under the direct influence of surface water (GWUDISW) determination acceptable to the state health officer shall be provided for all new wells.

a. Part of this determination shall include the proper submission of one or more 1 micron filters through which at least 500 gallons of produced groundwater being tested have passed at a regulated flow rate over a period of no more than a 24 hours.

b. Such filters shall be refrigerated, as appropriate, and delivered to a laboratory for the identification of insects or other macroorganisms, algae, rotifers and large diameter pathogens such as Giardia or Cryptosporidium [see USEPAs "Consensus Method for Determining Groundwaters under the Direct Influence of Surface Water Using Microscopic Particulate Analysis (MPA)"].

c. The laboratory utilized shall be recognized by the USEPA for such work and it shall identify such macroorganisms found on the filter and, in the case of Giardia or Cryptosporidium, whether any observed specimens were alive or dead.

d. In addition, the laboratory report shall indicate the overall risk as being either a low, medium, or high occurrence of such macroorganisms.

e. This information, in combination, with other factors mentioned under the definition of GWUDISW contained in Chapter 11 of this Part, shall be used by the state health officer in determining whether or not a new well will be deemed as a GWUDISW source.

3. Microbiological quality. After disinfection of each new, modified or reconditioned groundwater source, one or more water samples shall be submitted to a LDH-OPH-certified drinking water laboratory for microbiological analysis with satisfactory results reported to the state health officer prior to placing the well into service.

4. Physical, chemical and radiological characteristics. Every new, modified or reconditioned groundwater source shall be examined for applicable physical, chemical and radiological characteristics as required by the state health officer by tests of representative samples in a LDH-OPH certified drinking water laboratory, with results reported to the state health officer.

a. Samples shall be collected and analyzed at the conclusion of the test pumping procedure.

b. Field determinations of physical and chemical constituents or special sampling procedures may be required by the state health officer.

D. Groundwater location shall conform to the following requirements.

1. Well location. The state health officer shall be consulted prior to design and construction regarding proposed well location as it relates to required separation between existing and potential sources of contamination and groundwater development.

a. All ground water sources of water supply shall comply with the following requirements.

i. The ground surface within a safe horizontal distance of the source in all directions shall not be subject to flooding (as defined in Footnote 4 of a.ii below) and shall be so graded and drained as to facilitate the rapid removal of surface water. This horizontal distance shall in no case be less than 10 feet for potable water supplies.

ii. Every potable water well, and the immediate appurtenances thereto that comprise the well, shall be located at a safe distance from all possible sources of contamination, including but not limited to, privies, cesspools, septic tanks, subsurface tile systems, sewers, drains, barnyards and pits below the ground surface. The horizontal distance from any such possible source of pollution shall be as great as possible, but in no case less than the following minimum distances, except as otherwise approved by the state health officer.

Table 169.D.1.a.ii. Sources of Contamination	Distance in Feet
Septic tanks	50
Storm or sanitary sewer	50¹
Cesspools, outdoor privies, oxidation ponds, subsurface absorption fields, pits, mechanical sewage treatment plants, etc.	100²
Another water-well	25³
Sanitary landfills, feed lots, manure piles, solid waste dumps and similar installations	100
Drainage canal, ditch or stream	50⁴

¹ This distance may be reduced to 30 feet if the sewer is of ductile iron with water-tight joints or pressure rated plastic pipe.

² For a private water well this distance may be reduced to 50 feet.

³ This minimum distance requirement does not take into consideration the effects of interference from pumping nearby wells in the same aquifer.

⁴ Horizontally measured from the water's edge to the well at the highest water level which may have occurred in a 10-year period.

iii. No toilet, sewer, soil pipe or drain shall be located above or where leakage therefrom can reach any water storage basin, reservoir or source of water supply.

iv. There shall be no unauthorized pits or unfilled spaces below level of ground surface, any part of which is within 50 feet of such water supply, except properly constructed well, pump, or valve pits as covered under §329. A.4 of this Part.

v. Earth formations above the water-bearing stratum shall be of such character and depth as to exclude contamination of the source of supply by seepage from the surface of the ground.

b. A well shall be located far enough from a building to allow reworking or rehabilitation with a drilling rig. A well shall not be located below ground surface, such as in pits and basements, and shall not be located within the foundation of a building, except a building constructed solely to house pumping and water system equipment.

c. Groundwater development shall be in conformance with the applicable standards, laws, and regulations of the government agency or agencies having jurisdiction.

2. Continued sanitary protection of the well site from potential sources of contamination shall be provided by having a minimum 50-foot radius of ownership and a minimum 100-foot radius of control from the well head. The radius of control required beyond the minimum 50-foot radius of ownership shall be provided either through ownership, zoning, easements, leasing or other means acceptable to the state health officer which shall be maintained for the life of the well until the well is ultimately properly abandoned.

3. Wellhead Protection. Wellhead protection assessment for continued protection of the wellhead from potential sources of contamination shall be provided as determined by the state health officer.

E. General Well Construction. All wells constructed to serve a potable water supply shall be constructed in accordance with LAC 56, Part I, Water Wells. Drillers of wells that serve a potable water supply shall comply with these requirements pursuant to Louisiana Revised Statutes 38:2226, 38:3098-3098.8. In addition, the following requirements shall be met.

1. Drilling fluids and additives shall:

a. not impart any toxic substances to the water or promote bacterial contamination; and

b. be acceptable to the state health officer.

2. Minimum protected depths of drilled wells shall provide watertight construction to such depth as may be required by the state health officer, to:

a. exclude contamination; and

b. seal off formations that are, or may be, contaminated or yield undesirable water.

3. All well and spring basin casings or curbings shall extend a safe distance below the ground surface. The minimum depth of casings or curbings shall not be less than 50 feet in the case of public water supplies and not less than 10 feet in the case of private water supplies.

4. Polyvinyl Chloride Plastic (PVC). The state health officer may approve the use of PVC casing for all or for limited applications. PVC casing shall not be used at sites where permeation by hydrocarbons or degradation may occur.

5. Other Nonferrous Casing Materials. Approval of the use of any nonferrous material as well casing shall be subject to special determination by the state health officer prior to submission of plans and specifications. Nonferrous material proposed as a well casing must be resistant to the corrosiveness of the water and to the stresses to which it will be subjected during installation, grouting and operation.

6. Packers. Packers shall be of material that will not impart taste, odor, toxic substances or bacterial contamination to the well water. Lead packers shall not be used.

7. Screens. Screens shall be provided with a bottom plate or washdown bottom fitting of the same material as the screen.

8. Upper terminal well construction shall be in accordance with the following requirements.

a. In wells with pipe casings, the casings shall project at least 12 inches above ground level or the top of the cover or floor, and the cover or floor shall slope away from the well casing or suction pipe in all directions.

i. Dug well linings shall extend at least 12 inches above the ground surface and cover installed thereon. The cover shall be watertight, and its edges shall overlap and extend downward at least 2 inches over the walls or curbings of such wells.

ii. In flood-prone areas the top of the casing shall be at least two feet above the 100-year flood elevation, but in no case less than two feet above the ground surface.

b. Where a well house is constructed, the floor surface shall be at least six inches above the final ground elevation.

c. Sites subject to flooding shall be provided with an earth mound to raise the pumphouse floor to an elevation at least two feet above the 100-year flood elevation or other suitable protection as determined by the state health officer.

d. Protection from physical damage shall be provided as required by the state health officer.

e. The upper terminal shall be constructed to prevent contamination from entering the well.

f. Where well appurtenances protrude through the upper terminal, the connections to the upper terminus shall be mechanical or welded connections that are water tight.

9. Disinfection of every new, modified or reconditioned groundwater source shall:

a. be provided after completion of work, if a substantial period elapses prior to test pumping or placement of permanent pumping equipment;

b. be provided after placement of permanent pumping equipment; and

c. be done in accordance with AWWA C654 or method approved by the state health officer.

10. Well Abandonment. Abandoned water wells and well holes shall be plugged in accordance with LAC 56, Part I, Water Wells.

F. Testing and records shall comply with the following requirements.

1. Yield and Drawdown Tests shall:

a. be conducted in accordance with a protocol pre-approved by the reviewing authority;

b. be performed on every production well after construction or subsequent treatment and prior to placement of the permanent pump;

c. utilize methods clearly indicated in the project specifications;

d. be performed with a test pump with a capacity at least 1.5 times the flow anticipated at maximum anticipated drawdown;

e. shall provide, as a minimum, for continuous pumping for at least 24 hours at the design pumping rate or until stabilized drawdown has continued for at least six hours when test pumped at 1.5 times the design pumping rate, or as required by the state health officer;

f. provide the following data to be submitted to the state health officer:

i. test pump capacity-head characteristics;

ii. static water level;

ii. depth of test pump setting;

iii. time of starting and ending each test cycle; and

iv. the zone of influence for the well or wells;

g. provide a report which details recordings and graphic evaluation of the following at one hour intervals or less as may be required by the state health officer:

i. pumping rate;

ii. pumping water level;

iii. drawdown; and

iv. water recovery rate and levels;

h. at the discretion of the state health officer, more comprehensive testing may be required.

2. Plumbness and alignment shall conform to the following requirements.

a. Every well shall be tested for plumbness and alignment in accordance with AWWA Standard for Water Wells (A100).

b. The test method and allowable tolerance shall be clearly stated in the specifications.

c. If the well fails to meet these requirements, it may be accepted by the engineer if it does not interfere with the installation or operation of the pump or uniform placement of grout or affect long term integrity.

3. Geological data shall:

a. be determined from samples collected at 5-foot intervals and at each pronounced change in formation;

b. be recorded and submitted to the Louisiana Department of Natural Resources, Office of Conversation (DNR-OC) and the state health officer.

c. be supplemented with a drillers log, accurate geographical location such as latitude and longitude or GIS coordinates, and other information on accurate records of drill hole diameters and depths, assembled order of size and length of casing, screens and liners, grouting depths, formations penetrated, water levels, and location of any blast charges.

4. The owner of each well shall retain all records pertaining to each well, until the well has been properly abandoned.

G. Aquifer Types and Construction Methods. Aquifer types and construction methods shall conform to the following requirements.

1. Criteria for Sand or Gravel Wells

a. If clay or hard pan is encountered above the water bearing formation, the permanent casing and grout shall extend through such materials or at least 50 feet below the original ground elevation, whichever is lower.

b. If a sand or gravel aquifer is overlaid only by permeable soils the permanent casing and grout shall extend to at least 50 feet below original or final ground elevation, whichever is lower. Excavation of topsoil around the well casing should be avoided.

c. If a temporary surface casing is used, it shall be completely withdrawn.

d. If a permanent surface casing is used, it shall be grouted in place.

2. The following requirements shall apply to gravel pack materials.

a. Gravel pack materials shall

i. be sized based on sieve analysis of the formation; and

ii. be well-rounded particles, 95 percent siliceous material, that are smooth and uniform, free of foreign material, properly sized, washed and then disinfected immediately prior to or during placement.

b. Gravel pack installation shall:

i. be in one continuous operation.

ii. provide the material be placed in a manner that prevents segregation and gradation during placement.

c. The annular space between the well screen and the hole shall be adequate to allow proper placement of gravel pack.

d. 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.

e. Gravel refill pipes located in the grouted annular opening shall be surrounded by a minimum of 1 1/2 inches of grout.

f. Gravel pack shall extend above the highest well screen with an allowance for settling.

g. Protection from leakage of grout into the gravel pack or screen shall be provided.

h. Permanent inner casing and outer casings shall meet requirements of §169. E.4 of this Part.

3. Radial collectors shall conform to the following:

a. Locations of all caisson construction joints and porthole assemblies shall be indicated.

b. The caisson wall shall be reinforced to withstand the forces to which it will be subjected.

c. Radial collectors shall be in areas and at depths approved by the state health officer.

d. Provisions shall be made to assure that radial collectors are essentially horizontal.

e. The top of the caisson shall be covered with a watertight floor.

f. All openings in the floor shall be curbed and protected from entrance of foreign material.

g. The pump discharge piping shall not be placed through the caisson walls. In unique situations where this is not feasible, a water tight seal must be obtained at the wall.

4. Infiltration lines should be considered only where geological conditions preclude the possibility of developing an acceptable drilled well.

a. The area around infiltration lines shall be under the control of the water purveyor for a distance acceptable to or required by the state health officer.

b. Flow in the lines shall be by gravity to the collecting well.

c. Water from infiltration lines shall be considered as groundwater under the direct influence of surface water unless demonstrated otherwise.

5. Limestone or sandstone wells, where the depth of unconsolidated formations is more than 50 feet, the permanent casing shall be firmly seated in uncreviced or unbroken rock.

a. Grouting requirements shall be determined by the state health officer.

b. Where the depth of unconsolidated formations is less than 50 feet, the depth of casing and grout shall be at least 50 feet or as determined by the state health officer.

6. Naturally flowing wells shall require special consideration by the state health officer where there is an absence of an impervious confining layer.

a. Flow shall be controlled. Overflows shall discharge at least 18 inches above grade and flood level, and be visible. Discharge shall be to an effective drainage structure.

b. Permanent casing and grout shall be provided.

c. If erosion of the confining bed appears likely, special protective construction may be required by the state health officer.

H. Well Pumps, Discharge Piping and Appurtenances. Well pumps, discharge piping and appurtenances shall conform to the following requirements.

1. Line Shaft Pumps. Wells equipped with line shaft pumps shall:

a. have the casing firmly connected to the pump structure or have the casing inserted into a recess extending at least one-half inch into the pump base;

b. have the pump foundation and base designed to prevent water from coming into contact with the joint; and

c. use lubricants that meet NSF International/American National Standards Institute (NSF/ANSI) Standard 60 or use well water itself as a lubricant.

d. All water pumps shall be so constructed and installed as to prevent contamination of the water supply.

i. Where pumps or pump motors are placed directly over the well, the pump or motor shall be supported on a base provided therefor. The well casing shall not be used to support pump or motor. This requirement shall not apply to submersible pumps/motors and single-pipe jet pumps/motors. The pump or motor housing shall have a solid watertight metal base without openings to form a cover for the well, recessed to admit the well casing or pump suction. The well casing or pump suction shall project into the base at least 1 inch above the bottom thereof, and at least 1 inch above the level of the foundation on which the pump rests. The well casing shall project at least 12 inches above ground level or the top of the floor.

ii. Where power pumps are not placed directly over the well, the well casing shall extend at least 12 inches above the floor of the pump house. In flood-prone areas the top of the casing shall extend at least two feet above the 100-year flood elevation, but in no case less than two feet above the ground surface. The annular space between the well casing and the suction pipe shall be closed by a sanitary well seal to prevent the entrance of contamination.

2. Submersible Pumps. Where a submersible pump is used:

a. the top of the casing shall be effectively sealed against the entrance of water under all conditions of vibration or movement of conductors or cables; and

b. the electrical cable shall be firmly attached to the riser pipe at 20 foot intervals or less.

3. Discharge Piping. The design criteria for discharge piping is as follows.

a. The discharge piping shall:

i. be designed to minimize friction loss;

ii. have control valves and appurtenances located above the pumphouse floor when an above-ground discharge is provided;

iii. be protected against the entrance of contamination;

iv. be equipped with a check valve in or at the well, a shutoff valve, a pressure gauge, and a means of measuring flow;

v. be equipped with a smooth nosed sampling tap located at a point before any treatment chemicals are applied. The sample tap shall be at least 18-inches above the floor to facilitate sample collection.

vi. where applicable, be equipped with an air release-vacuum relief valve located upstream from the check valve, with exhaust/relief piping terminating in a down-turned position at least 18 inches above the floor and covered with a 24 mesh corrosion resistant screen;

vii. be valved to permit test pumping and control of each well;

viii. have all exposed piping, valves and appurtenances protected against physical damage and freezing;

ix. be properly anchored to prevent movement, and be properly supported to prevent excessive bending forces;

x. be protected against surge or water hammer;

xi. conform to §235 of this Part; and

xii. be constructed so that it can be disconnected from the well or well pump to allow the well pump to be pulled.

b. The discharge piping should be provided with a means of pumping to waste, but shall not be directly connected to a sewer.

c. For submersible, jet and line shaft pumps, the discharge, drop or column piping inside the well shall:

i. conform to §235 of this Part; where such standards exist, or in the absence of such standards, conform to applicable product standards and be acceptable to the state health officer. Any lubricants, fittings, brackets, tape or other appurtenances shall meet NSF/ANSI Standards 60/61, where applicable; and

ii. be capable of supporting the weight of the pump, piping, water and appurtenances and of withstanding the thrust, torque and other reaction loads created during pumping. The actions of fatigue from repeated starting and stopping of the pump shall be considered when choosing a pipe and fittings.

4. Pitless Well Units. Pitless well units shall conform to the following standards and requirements.

a. The state health officer must be contacted for approval of specific applications of pitless units.

b. Pitless units shall:

i. be shop-fabricated from the point of connection with the well casing to the unit cap or cover;

ii. be threaded or welded to the well casing;

iii. be of watertight construction throughout;

iv. be of materials and weight at least equivalent and compatible to the casing;

v. have field connection to the lateral discharge from the pitless unit of threaded, flanged or mechanical joint connection; and

vi. terminate at least 18 inches above final ground elevation or three feet above the 100-year flood level or the highest known flood elevation, whichever is higher, or as the state health officer directs.

c. The design of the pitless unit shall make provision for:

i. access to disinfect the well;

ii. a properly constructed casing vent meeting the requirements of §169.H.6 of this Part;

iii. facilities to measure water levels in the well (see §169.H 7);

iv. a cover at the upper terminal of the well that will prevent the entrance of contamination;

v. a contamination-proof entrance connection for electrical cable;

vi. an inside diameter as great as that of the well casing, up to and including casing diameters of 12 inches, to facilitate work and repair on the well, pump, or well screen; and

vii. at least one check valve within the well casing or in compliance with requirements of the state health officer.

d. If the connection to the casing is by field weld, the shop-assembled unit must be designed specifically for field welding to the casing. The only field welding permitted will be that needed to connect a pitless unit to the casing.

5. Pitless Adapters. Pitless adapters may be acceptable at the discretion of the state health officer. The use of any pitless adapter must be pre-approved by the state health officer.

6. Casing Vent. All potable water well casings shall be vented to atmosphere as provided below, with the exception that no vent will be required when single-pipe jet pumps are used.

a. All potable water well vents shall be so constructed and installed as to prevent the entrance of contamination.

b. All vent openings shall be piped water tight to a point not less than 24 inches above the 100-year flood elevation, but in no case less than 24 inches above the ground surface.

i. Such vent openings and extensions thereof shall be not less than 1/2 inch in diameter, covered with a 24 mesh, corrosion resistant screen with extension pipe firmly attached thereto.

ii. The openings of the vent pipes shall face downward and shall be screened to prevent the entrance of foreign matter.

7. Water Level Measurement. Provisions shall be made for periodic measurement of water levels in the completed well.

a. Where pneumatic water level measuring equipment is used it shall be made:

i. using corrosion-resistant materials attached firmly to the drop pipe or pump column; and

ii. in such a manner as to prevent entrance of foreign materials.

8. Liners may be acceptable at the discretion of the state health officer. The use of any liner must be pre-approved by the state health officer.

La. Admin. Code tit. 51, § XII-169

Promulgated by the Department of Health, Office of Public Health, LR 44305 (2/1/2018), effective 8/1/2018, Amended LR 481101 (4/1/2022).

AUTHORITY NOTE: Promulgated in accordance with the provisions of R.S. 40:4(A)(8), 40:4.13.D.(1)(2) and 40:5(A)(2)(3)(5)(6)(7)(17).