United States Department of Agriculture 317-CPS-1

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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 

COMPOSTING FACILITY 

CODE 317 

(no)

DEFINITION 

A structure or device to contain and facilitate an aerobic microbial ecosystem for the decomposition of

manure, other organic material, or both, into a final product sufficiently stable for storage, onfarm use, and

application to land as a soil amendment. 

PURPOSE 

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

• Reduce water pollution potential 

• Conserve energy by reducing mass and improving handling characteristics of organic waste solids 

• Reuse organic waste as animal bedding 

• Transform organic waste into a soil amendment that improves soil health, provides slow-release

plant-available nutrients, and suppresses plant disease 

CONDITIONS WHERE PRACTICE APPLIES 

This practice applies where at least one of the following conditions occurs: 

• Organic solid wastes to be composted derive primarily from agricultural production or processing 

• The compost can be reused in the operation, utilized for crop production, improve soil health, or

marketed to the public 

This practice applies construction of a structure or device to contain and facilitate the composting process.

Use NRCS Conservation Practice Standard (CPS) Nutrient Management (Code 590) for producer land

application of finished compost to provide nutrients or as a soil amendment. 

This practice does not apply to the routine handling of livestock and poultry carcasses. Use NRCS

Conservation Practice Standard (CPS) Animal Mortality Facility (Code 316) for carcass composting facility

design. 

This practice does not apply to routine storage and handling of animal manure solids. Use NRCS CPS

Waste Storage Facility (Code 313) for animal manure solids dry stack facilities. 

CRITERIA 

General Criteria Applicable to All Purposes 

Plan, design, and construct the composting facility to comply with all Federal, State, and local laws and

regulations. The landowner is required to obtain all necessary permits for project installation prior to

construction. 
Siting 

Locate and design the composting facility so it is outside the 100-year floodplain unless site restrictions

require locating it within the floodplain. If located within the floodplain, protect the facility from inundation

or damage from a 25-year flood event. Additionally, follow the policy found in the NRCS General Manual

(GM) (Title 190), Part 410, Subpart B, Section 410.25, “Flood Plain Management,” which may require

providing additional protection for storage structures located within the floodplain. 

Locate facility a minimum of 50 feet from wells, streams, or other water features. Additional distances may

be required by local or State laws. Redirect upslope surface runoff away from the composting site. 

Locate the composting facility to ensure the floor is 2 feet or more above the site-identified seasonal high

ground water table unless special design features are incorporated that will address the potential for

leaching of contaminants to the water table. The water table may be lowered by use of drains to meet this

requirement. 

Ensure all-weather access to the composting facility. Use NRCS CPSs Access Road (Code 560) or Heavy

Use Area (Code 561) if the site lacks appropriate existing access. 

Capacity 

Size the composting facility in accordance with NRCS National Engineering Handbook (NEH) (Title 210),

Part 637, Chapter 2, “Composting.” Design the composting facility to accommodate the amount of organic

waste feedstock generated for active composting and compost curing, along with the needed volume of

additional bulking material or carbon source to achieve the composting action. Active composting includes

both the primary and secondary stages of composting. Space for both the active composting and compost

curing are required for making a stable finished compost product. Select facility dimensions to

accommodate all stages of composting with space for turning, handling, and processing. 

Moisture 

Orient and design the facility to enable the management of the compost moisture content. A water source

is needed for adding moisture in dry conditions. If considerable precipitation is likely, design a cover.

Minimize blown in precipitation on covered facilities by providing a roof overhang or orient the open side of

the facility away from the prevailing wind direction. 

Roofs and roof runoff 

If a roof is needed, design the roof using NRCS CPS Roofs and Covers (Code 367). Use NRCS CPS

Roof Runoff Structure (Code 558) when designing the collection, control, and conveyance of runoff from a

roof that could pose a resource concern. Use NRCS CPS Underground Outlet (Code 620) when designing

pipe outlets to prevent erosion or contamination of clean runoff water by composting materials. 

Foundation and structure 

Design the facility to prevent the contamination of ground water resources. Evaluate site soils for depth to

water table, permeability, texture, and bearing strength based on the design load and frequency of use. 

For the design of a stable surface treatment, where appropriate, use criteria in NRCS CPS Heavy Use

Area Protection (Code 561). Use the criteria in NRCS CPS Waste Storage Facility (Code 313) when

designing composting facility slabs, walls, and floors. Prevent seepage of compost stack leachate in

amounts that would pollute surface or ground water with collection and disposal of liquids in a safe

manner, as necessary. Where seepage will be an issue, use NRCS CPSs Pond Sealing or Lining—

Geomembrane or Geosynthetic Clay Liner (Code 521), Pond Sealing or Lining—Concrete (Code 522), or

Pond Sealing or Lining—Compacted Soil Treatment (Code 520). Guidance on restricting seepage through

foundation and subgrade material can be found in NRCS 210-NEH, Part 651, Chapter 10, Appendix 10D,

“Design and Construction Guidelines for Impoundments Lined with Clay or Amendment-treated Soil.”

Seepage control may not be necessary on sites that have a roof, waste material with little seepage

potential, or in certain climates. 

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Power supply 

Where needed for mechanically stirred composting systems, all power supply and electrical components,

including wiring, boxes, and connectors, must meet the requirements of the National Electric Code. If the

power supply is located in an area that is reasonably accessible by machinery, protect it with strategically

placed bollards or other appropriate safety measures. 

Wastewater 

If leachate or contaminated runoff is anticipated, use NRCS CPS Waste Transfer (Code 634) for collection

and conveyance of any leachate or contaminated runoff from the composting facility to a wastewater

storage or treatment facility for further management or reuse. Use NRCS CPS Waste Storage Facility

(Code 313) or other applicable NRCS CPS for that purpose. 

Safety 

Incorporate safety and personnel protection features and practices into the facility and its operation to

ensure biosecurity and minimize the occurrence of equipment and fire hazards associated with the

composting process as appropriate. For composting bins, limit the stack height to 6 feet unless a forced

aeration system is provided. This will allow air to reach the center of the pile for proper composting and

minimize the potential for spontaneous combustion. 

CONSIDERATIONS 

Select the type of composting facility and composting method based on landowner’s goals, kind of organic

waste solids, planned quality of finished compost, operator’s equipment, labor, time, and land available for

the facility footprint, and resource concerns. 

Consider the landscape elements when locating the facility. Landscape features can buffer prevailing

winds which will minimize odors and protect visual resources. 

Where appropriate, consider all-weather access roads for the composting facility site. 

When locating the facility, consider a location away from crops typically consumed raw, food contact

surfaces, water distribution systems, and other soil amendment sources where it could become a potential

source of contamination. 

If the site is located where fields have been artificially drained consider potential water quality issues.

Locate or remove field tiles where seepage from the composting facility to ground or surface water is a

resource concern. 

Consider equipment access for the facility location and determine if a heavy use area apron is needed to

properly manage the compost. 

If the composting facility is in a higher precipitation area or the site will have heavy vehicle traffic, consider

using a concrete base for the facility. 

When designing for windrows, consider the compost site grade and pile alignment. Grade site to prevent

ponding from occurring. Align windrows north to south to maximize solar warming. 

Consider protecting the composting facilities from wind in cold or dry climates. Wind in cold climates can

cause heat loss through convection, limiting microbial metabolism. In low humidity climates wind can

cause drying, limiting water availability for microbial metabolism. Dry, pulverized compost is also

susceptible to undesirable wind transport from the facility. 

Consider the options for finished compost storage. Storage space may be included in the compost curing

space or in a separate facility that also protects the resources. 

Consider the impact of using treated lumber for the construction of composting facilities on the quality and

acceptability of the compost. For production of certified organic compost have the producer consult with

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an organic certifier as to the use and acceptability of treated lumber that will meet the design life span for

bins and compost storage structures. 

PLANS AND SPECIFICATIONS 

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

intended use, including, but not limited to— 

• Plan view showing layout and location of composting facility; if applicable, access road to facility;

and setback distances from water bodies, streams, sensitive areas, property line, etc. 

• Drainage and grading plan showing excavation, fill, and drainage containment, as appropriate. 

• Pertinent elevations of the facility. 

• Notification to the landowner and contractor of their responsibility to locate all buried utilities in the

project area. 

• Subgrade work (excavation, earthfill/drainfill, compaction requirements). 

• Structural details of all components. 

• Construction material quantities and specifications. 

• Safety features (i.e., fire suppression). 

OPERATION AND MAINTENANCE 

Develop an operation and maintenance plan that is consistent with the purposes of this practice and the

design life of the composting facility. Outline periodic inspections and maintenance of equipment and

facilities. Include structural elements of the facility to be inspected or maintained, an inspection interval

time frame, and recommendations for preventative maintenance. 

Describe essential safety features of the facility to provide protection from or prevention of a compost fire. 

Provide procedures to monitor and maintain vibrant microbiological decomposition of the organic materials

according to the design and site conditions and pertinent nuances of the organic materials to be

composted. Guidance provided should be based on the needs and goals of the producer using literature

provided by local university extension publication; NRCS 210-NEH, Part 637, Chapter 2, “Composting”;

“NRAEAS 54: On-Farm Composting Handbook”; or other appropriate composting literature. Monitoring the

temperature and moisture content of composting material reflects the phases of successive populations of

microorganisms and their metabolism as they decompose the organic matter. The operation may need to

undergo some trial and error in the startup of a new composting facility while the operator determines an

efficient operating process. The operator must keep accurate records to aid in learning how to operate the

facility efficiently. 

Specify the types and volumes of animal waste and other sources of organic feedstock to be composted.

Provide information on planned compost recipe ingredients and the sequence for mixing and building the

compost piles. Direct the operator to land grant universities and other recognized entities that provide

compost mixture calculators to balance feedstocks to meet a target carbon-to-nitrogen (C:N) ratio and

moisture content. The NRCS CPS Waste Recycling (Code 633) may be used when nonagricultural

byproducts are included in the composting feedstock. 

Manage the compost for temperature, moisture, oxygen, and pH, as appropriate. Test the finished

compost, as appropriate, to assure the product is stable and no longer heating from biological

decomposition. Guidance for composting management, monitoring, and the testing of compost stability is

in NRCS 210-NEH, Part 637, Chapter 2, Section 637.0209(h), “Determination of compost stability.” 

Monitoring Documentation 

Provide a recordkeeping form for the operator to use listing at a minimum the date, amounts, and types of

material added, compost temperature, weather conditions, and actions taken to manage the compost.

Monitoring may include but is not limited to— 

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• Compost Mix.—Build a compost mix that encourages aerobic microbial decomposition and avoids

nuisance odors. Blend feedstock, build compost pile, and handle the compost mix to develop a

porous structure for uniform aeration during composting. 

• C:N Ratio.—Developing a composting recipe is a balancing act as both the C:N ratio and the

moisture content of the individual materials need to be within acceptable ranges. The

recommended initial C:N ratio of 20:1 to 40:1 for rapid composting is consistent with the nutrient

needs of the bacteria and fungi in the compost pile. The composting process relies on the balance

of carbon- and nitrogen-containing materials. If carbon is present in excessive amounts relative to

nitrogen so that the C:N ratio is above the optimal range, the composting process slows. For

composting animal mortalities, C:N ratios as low as 14:1 may be effective and practical. Lower C:N

ratios may lead to increased odor and ammonia loss. 

• Carbon.—If needed, store a dependable source of carbonaceous material with a high C:N ratio for

mixing with nitrogen-rich waste materials. Minimize odors and ammonia volatilization by blending

sufficient carbonaceous material with the nitrogenous material (C:N ratio). 

• Bulking Materials.—Add bulking materials to the mix as necessary to enhance aeration. The bulking

material may be carbonaceous material used in the mix, slowly-degradable natural organic

material, or nonbiodegradable or slowly biodegradable material salvaged from the compost mix at

the end of the cycle. Make provisions for the salvage of any nonbiodegradable or slowlydecomposing material used in the composting process. 

• Moisture Level.—Throughout the composting period, maintain moisture in the compost mix within

the range of 40 to 60 percent (wet basis). Prevent excess moisture from accumulating in the

compost. This may require covering the pile. 

• Temperature of Compost Mix.—Manage the compost to attain and then maintain the target internal

temperature for the duration required to meet the desired compost product. It will be necessary for

the compost to reach 145°F to adequately kill weed seeds. Closely monitor temperatures above

165°F as that will inhibit the composting process by destroying the thermophilic bacteria. Take

action immediately, generally applying water and then mixing, to cool piles that have reached

temperatures above 185°F to prevent combustion. Include the need to train workers regarding the

recognition of the potential for spontaneous combustion for their safety and to prevent damages. 

• Turning/Aeration.—Schedule the turning/aeration frequency to attain the desired amount of oxygen,

moisture removal, and temperature control appropriate for the composting method used to optimize

aerobic biodegradation. 

• Odors.—If the initial compost mixing and compost pile structure do not accomplish adequate odor

reduction, strategies may include altering the recipe to add more carbon, modifying the moisture

content, modifying the pH by applying a material compatible with compost quality and with any

specifications for its end use (e.g., certified organic), or using a biological inoculant. 

Composting 

Time, temperature, and turning the compost materials is critical, and if not carried out properly the

composted materials may have limited uses. 

Composted materials, to be used in the same way as manure solids, must store safely without

undesirable odors. Typically, this requires a temperature phase to be maintained above 104°F for 5 days

with at least 4 hours above 131°F during that time period. 

Compost, for vegetable crops and off-farm use or sale, or compost used on any organic crops, must meet

USDA National Organic Program requirements. For this, the compost must be stable when finished, be

adequately dried, and contain limited quantities of pathogens. This includes compost used onfarm for

crops subject to the Food Safety Modernization Act (FSMA) Standards for the Growing, Harvesting,

Packing, and Holding of Produce for Human Consumption (Produce Safety Rule). 

• For processing compost in either a static aerated pile or in-vessel compost system, the temperature

of the compost is required to be maintained between 131°F and 170°F for 3 days. 

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• For a windrow system the temperature of the compost is required to be between 131°F and 170°F

for 15 days with a minimum of five turnings of the compost to ensure the windrow is mixed and

evenly composted. 

For crops subject to the FSMA Produce Safety Rule, direct growers to the rule for additional criteria that

may be applicable. See https://www.fda.gov/food/food-safety-modernization-act-fsma/fsma-final-ruleproduce-safety. 

Local compost certification regulations may vary. 

Use of Finished Compost 

Compost can be reused in the operation and utilized for crop production or bedding. It also serves to

improve soil quality and can be marketed to the public. 

Use NRCS CPS Nutrient Management (Code 590) for producer land application of finished compost to

provide nutrients, as a soil amendment, or both where the finished compost is stable decomposed

material that will not reheat, is reduced in pathogenic organisms, and most weed seed are no longer

viable. 

When applying a general compost material that is not a stable pathogen-reduced product, follow NRCS

CPS Nutrient Management (Code 590) criteria for manure solids application. For this, abide by any State

or local rules that may detail crop type, location, and timing restrictions for manure application. 

REFERENCES 

Rynk, R., M. van de Kamp, G.B. Willson, et al. 1992. On-Farm Composting Handbook, NRAEAS-54.

Northeast Regional Agricultural Engineering Service. Ithaca, NY.

https://ecommons.cornell.edu/handle/1813/67142

USDA Agricultural Marketing Service. 2000. National Organic Program. 7 CFR 205.203, (c) (2). Soil

Fertility and Crop Nutrient Management Practice Standard. Washington, D.C. 

USDA NRCS. 2000. National Engineering Handbook (Title 210), Part 637, Chapter 2, Composting.

Washington, D.C. https://directives.sc.egov.usda.gov/

U.S. Food and Drug Administration. 2015. Food Safety Modernization Act. 21 CFR 112. Standards for the

Growing, Harvesting, Packing, and Holding of Produce for Human Consumption. Silver Spring, MD.

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