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NRCS reviews and periodically updates conservation practice standards. To obtain the current 

version of this standard, contact your Natural Resources Conservation Service State office or 

visit the Field Office Technical Guide online by going to the NRCS website at 

https://www.nrcs.usda.gov/ and type FOTG in the search field. 

USDA is an equal opportunity provider, employer, and lender.

Natural Resources Conservation Service 

CONSERVATION PRACTICE STANDARD 

WATER WELL 

CODE 642 

(no)

DEFINITION 

A hole drilled, dug, driven, bored, jetted, or otherwise constructed into an aquifer for agricultural water

supply. 

PURPOSE 

This practice is used to accomplish one or more of the following purposes: 

• Address the need for adequate livestock water quality and quantity 

• Provide water for terrestrial wildlife 

• Provide irrigation water 

CONDITIONS WHERE PRACTICE APPLIES 

This practice applies to all types of agricultural land where the quality and quantity of underground water is

appropriate for the intended purpose. 

This practice does not apply to— 

• Wells constructed for domestic or public water supply. 

• Monitoring wells, NRCS Conservation Practice Standard (CPS) Monitoring Well (Code 353),

injection wells, temporary test wells, or piezometers. 

• Pumps, surface supply lines, storage facilities, and related appurtenances. 

CRITERIA 

General Criteria Applicable to All Purposes 

Law and regulations 

The investigation, design, and installation of an agricultural water supply well must comply with all

applicable governmental regulations, laws, permits, licenses, and registrations according to NRCS Title

450, General Manual (GM), Part 405, Subpart A, “Compliance with Laws and Regulations.” Where

applicable laws and regulations do not exist, follow industry standards, such as— 

• A proposed well must comply with criteria in the current version of American Water Works

Association (AWWA), A100-15, “Water Well Standard.” 

• A proposed irrigation well must comply with criteria in the current version of American Society of

Agricultural and Biological Engineers (ASABE or ASAE) EP400.3, “Designing and Constructing

Irrigation Wells.” 

• The well design and installation must comply with criteria in the current version of National Ground

Water Association (NGWA) 01, “Water Well Construction Standard.” 
Roles and responsibilities 

Licensed water well driller is responsible for drilling and installing the water well, according to State

regulations. 

The landowner is responsible for obtaining all necessary permits, rights, or approvals according to NRCS

450-GM-405 and applicable laws, rules, and regulations. 

The landowner and/or licensed contractor are responsible for locating all buried utilities in the project area,

including drainage tiles and other structural measures. 

Site suitability 

Use reliable local experience, and review all relevant geologic maps, reports, and well records maintained

by State and Federal agencies to evaluate ground water quantity and quality. When local hydrogeologic

data are limited or conditions are complex and uncertain, conduct onsite evaluation to provide

professional recommendations regarding site suitability. 

Locate the well according to the Occupational Safety and Health Administration (OSHA) Standard

1926.1408 (h), “Power line safety (up to 350 kV)–equipment operations” to comply with setback distances

from overhead or underground utility lines or other safety hazards. 

Locate the well away and upgradient from potential surface and subsurface contamination or pollution and

areas subject to flooding, according to State regulations. In determining hydraulic gradient, consider both

pumped and static water levels. 

Laterally locate the well to comply with applicable conservation practice standards and State-specific

water well setback zones and prohibitions. 

Clear the site of all trees, brush, and obstructions. Locate the drill rig, related equipment, and the well on

relatively flat, reasonably dry, working surface for a safe and effective working environment. 

Wellhead protection 

Divert all surface runoff, precipitation, and drainage away from the wellhead. Compact, mound, and slope

earth material away from the wellhead. 

Protect the wellhead and associated appurtenances from contamination or damage by wildlife, livestock,

farm machinery, vehicle parking, or other harmful human activity. 

Grouting and sealing the casing 

When drilling into hard rock formations or physically stable geologic materials, install a minimum of 10 feet

of casing. 

For erodible, friable, or otherwise unstable materials, install watertight grouted casing. 

Install a watertight seal in the annulus of all well casing. Acceptable sealants include mortar containing

expansive hydraulic cement, bentonite-based grout, bentonite chips and pellets, sand-cement grout, neat

cement, or concrete. 

Use sealant, packers, or similar retaining device to isolate one or more aquifers or zones that produce

poor ground water quality to prevent commingling or cross-contamination. Provide a similar positive seal

to separate water-bearing zones where comingling is not desired. 

For artesian wells (flowing and nonflowing), grout the casing and geologic units directly above and below

the aquifer to retain its confining pressure. 

When casing extends to the borehole bottom, install a watertight end cap or grout seal to prevent entry of

geologic material. For designs requiring telescoped screen assemblies, install one or more sand-tight

seals between the top of the telescoped screen assembly and the casing. 

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After well completion, provide a suitably threaded, flanged, welded cap, or compression seal to prevent

entry of contaminants into the well. 

Casing materials 

Acceptable materials for casing include steel, iron, stainless steel, copper alloys, plastic, fiberglass,

concrete, or other material of equivalent strength, which have sufficient chemical resistance to the ground

water for the design life of the well. To prevent galvanic corrosion, do not join dissimilar metals. Select a

casing diameter to permit satisfactory installation and efficient operation of a submersible pump, if used.

Typically, the casing diameter should be a minimum of 2 inches larger than the maximum outside diameter

of the pump and pump column. 

Select casing material that can withstand all anticipated static and dynamic pressures imposed on the

casing while maintaining a watertight seal during installation, well development, and use throughout the

design life of the well. When needed, mechanically support casing during installation to maintain joint

integrity. Refer to NRCS National Engineering Handbook (NEH) (Title 210), Part 631, “Geology,” for

guidance in determining proper differential head limitations for approved casing materials. 

Screen and filter pack 

Screen slot size and filter pack (artificial or natural) must conform to the characteristics listed in ASTM

D5092, “Standard Practice for Design and Installation of Groundwater Monitoring Wells” and ASTM

D6725, “Standard Practice for Direct Push Installation of Prepacked Screen Monitoring Wells in

Unconsolidated Aquifers.” Use only manufactured well screen that consists of corrosion-resistant material. 

Install a well screen and filter pack (artificial or natural) if any of the following conditions exist: 

• Presence of a poorly graded, fine sand aquifer or heaving or caving sands; 

• Presence of a highly variable aquifer, such as alternating sand and clay layers; 

• Presence of a poorly cemented sandstone or other loosely compacted material; 

• Requirement for maximum yield from a low-yielding aquifer; 

• Hole drilled by reverse circulation. 

Refer to ASTM D5092 for filter pack quality criteria and filter pack and well screen slot size compatibility

with formation rock and soil. 

Use a prepacked well screen for horizontal, vertical, or angled wells. Use an artificial filter pack if natural

filter pack is unavailable. 

Screen and filter pack installation 

Position the well screen according to the depth of the water-bearing zone(s) below the ground surface and

thickness of the water-bearing zone penetrated by the drill hole. Install a conventional filter pack from the

bottom up and place in a manner that avoids segregation and bridging of particles. Install filter pack

according to NRCS 210-NEH-631, and ASTM D5092. 

When bentonite seals are allowed, hydrate bentonite to facilitate expansion and fill voids. Hydrate

bentonite according to manufacturer’s recommendations. 

For a screened well cased to the well bottom, install several extra feet of blank screen or casing at the

bottom of the well to accommodate sediment that passes through the well screens and settles to the

bottom of the well. 

Access port 

Install an access port with a minimum diameter of 0.5 inch to allow for unobstructed measurement of

depth of the water surface, or for the installation of a pressure gage for measuring shut-in pressure of a

flowing well. 

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Seal or cap access ports, pressure gages, and all other openings in the well cover to prevent entry of

unwanted materials and to discourage tampering. A removable cap is acceptable for an access port. 

Well development 

After completing well construction, but before conducting well performance (aquifer) tests, develop the

well to remove fines, drill cuttings, mud, drilling fluids, and additives. Well development is required for all

water wells. Pump the well at approximately 120 percent of the anticipated normal production rate until

water discharge is clear. Do not use the permanent pump to conduct any well development work. Refer to

ASTM 5521 “Standard Guide for Development of Groundwater Monitoring Wells in Granular Aquifers” for

well development procedure. 

Water quality testing 

If local water quality conditions are unknown or questionable, test the well water using parameters that

pertain to well performance or the suitability of the water for its intended usage. Test well water according

to NRCS CPS Groundwater Testing (Code 355). 

Disinfection 

Prior to chemical disinfection, remove foreign substances, such as grease, soil, sediment, joint dope, and

scum from the well and near the wellhead. Clean all pump parts before placing them into the well.

Disinfect the well using a chlorine compound at a concentration of a minimum 50 mg/L (50 ppm). 

Well performance (aquifer) testing 

Design the well so at maximum drawdown, the water surface does not drop to the top of the highest

screen or pump intake. Wait no less than 24 hrs after well development is completed and the water level

has stabilized, to conduct a pumping test for determining specific capacity and dynamic water levels.

Refer to NRCS 210-NEH-631 and 210-NEH, Part 650, Chapter 12, Section 650.1205, “Wells” for guidance

on conducting, recording, and analyzing pumping tests. 

Discharge water a minimum of 300 feet from the well and in such a way that reduces erosion to the land

surface and prevents potential artificial recharge during the test. 

Take all measurements from the top of well casing. 

CONSIDERATIONS 

Consider the following when planning and designing a water well: 

• Evaluating the potential for adverse interference with existing nearby production wells when

planning and designing the water well 

• Health impacts of nitrates in groundwater used for livestock consumption. In areas of nitrogen

fertilizer use, consider checking with the local Health Department for excess nitrogen levels in

ground water 

• Health impacts of ground water mineral content used for irrigation or animal watering. Minerals

contained in ground water, such as selenium, sodium, sulfate, and others have the potential to

negatively impact soil, plant and animal health 

• For (aquifer) testing, consider the potential for ground water overdraft and the long-term, safe

aquifer yield 

PLANS AND SPECIFICATIONS 

Develop plans and specifications that clearly describe requirements for applying the practice to achieve its

intended purposes. If not already specified in the documentation required by the State regulatory

authority, record the following information in the installation record: 

• Location of water well by Global Positioning System (GPS) coordinates or in a sufficiently detailed

narrative description to readily locate the well. 

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• Name of well owner. 

• Type of casing material or schedule, and whether new or used. 

• Height of casing extending aboveground surface. 

• Static water level measured from top edge of casing or from ground surface. 

• Well diameter, total well depth, and screened depth/interval. 

• Notification of whether aquifer is artesian or non-artesian. If well is flowing artesian, provide flow

rate and pressure. 

• Screen slot size and filter gradation (if used). 

• Drilling method and bore hole diameter. 

• Well development methods used. 

• Results of pump test, drawdown, pumping rate, specific capacity, and well efficiency. 

• Driller’s log for water-bearing and dry holes. 

• If water quality was tested, record the parameters and test results, date of sampling, name of

person who took sample, and name of laboratory that conducted tests. 

• Schematic drawing of well construction showing well diameter and depth, casing and liner

diameters, fill, bentonite, or grouting surface elevation, and top of well head elevation. 

• Disinfection method and solution used, and date the well is disinfected. 

OPERATION AND MAINTENANCE 

Prepare a site-specific plan for operation and maintenance of the water well. The owner is responsible for

keeping and maintaining well construction records with the maintenance plan. The owner must ensure

periodic inspection of the well for proper functioning and water quality. 

Do not store or mix agricultural chemicals, such as fertilizers and pesticides, or rinse containers within a

100-foot radius of the wellhead. 

Regular inspection must include conditions that affect well performance, based upon the well’s intended

use. As a minimum, these conditions include— 

• Declines in discharge, static level, maximum pumping level, and pressure (for artesian wells) that

are outside acceptable limits for the well design. 

• Appearance of sediment that may damage the well, pump, or appurtenances. 

• Changes in water quality including odor, color, taste, and chemistry. 

• Presence of algae or iron bacteria. 

For wells that have blank casing installed below the screen, periodically bail or flush the well to remove

excessive, accumulated sediment. 

In the maintenance record, include statements describing identified problems, corrective action taken and

date, and specific capacity of well before and after corrective action. The owner must remedy

unacceptable conditions in a timely manner. 

In the event the well becomes unserviceable, it may be decommissioned according to NRCS

Conservation Practice Standard Well Decommissioning (Code 351). 

REFERENCES 

American National Standards Institute National Groundwater Association (ANSI/NGWA-01-14). 2014.

Water Well Construction. 

American National Standards Institute/American Society of Agricultural Engineers (ANSI/ASAE). 2017.

American National Standard EP400.3, Designing and Constructing Irrigation Wells. 

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American National Standards Institute/American Water Well Association (ANSI/AWWA). 2015. American

National Standard, A100, Standard for Water Wells. American National Standard/American Water Well

Association, Denver, CO. AWWA catalog no: 41100-2015, http://www.awwa.org. 

ASTM D5521. 2018. Standard Guide for Development of Groundwater Monitoring Wells in Granular

Aquifers. ASTM International, West Conshohocken, PA. DOI: 10.1520/D5521_D5521M-18,

http://www.astm.org. 

ASTM D5092. 2016. Standard Practice for Design and Installation of Groundwater Monitoring Wells.

ASTM International, West Conshohocken, PA. DOI: 10.1520/D5092-D5092M-16, http://www.astm.org. 

ASTM D6725. 2016.Standard Practice for Direct Push Installation of Prepacked Screen Monitoring Wells

in Unconsolidated Aquifers. ASTM International, West Conshohocken, PA. DOI: 10.1520/D6725-D6725M16, http://www.astm.org. 

Occupational Safety and Health Administration. 2012. Power Line Safety (up to 350 kv) - equipment

operations. Safety and Health Regulations for Construction Standard - 1926.1408, Subpart CC. Retrieved

from https://www.osha.gov/laws-regs/regulations/standardnumber/1926/1926.1408. 

USDA NRCS. 2010. National Engineering Handbook (Title 210), Part 631..

https://directives.sc.egov.usda.gov/

USDA NRCS. 2012. National Engineering Handbook (Title 210), Part 651, Chapter 1,Laws, Regulations,

Policy, and Water Quality Criteria. https://directives.sc.egov.usda.gov/

USDA NRCS. 2012. National Engineering Handbook (Title 210), Part 650, Chapter 12, Section 650.1203,

Chapter 12, Wells. https://directives.sc.egov.usda.gov/

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