Water Quality & Management on Organic Farms

Water quality and management is an explicit NOP compliance requirement, not simply a best practice recommendation. Under 7 CFR § 205.200 and § 205.203, certified organic producers are required to implement management practices that maintain or improve the natural resources on their operation — including water quality.

Specifically, NOP requires certified producers to:

• Implement tillage and cultivation practices that minimize soil erosion and prevent contamination of surface water, groundwater, and wetlands (§ 205.203)

• Manage plant and animal materials in ways that do not contribute to the contamination of crops, soil, or water by plant nutrients, pathogenic organisms, heavy metals, or prohibited substances

• Avoid practices that would adversely affect the quality of surface or groundwater

• Maintain natural resource buffers and practices that protect water quality on and adjacent to the operation

These requirements connect directly to some of the most practical farm management decisions organic producers make: how and when manure is applied, how fields are buffered from waterways, how irrigation water is sourced and managed, and what tillage systems reduce runoff and erosion.

USDA NRCS's EQIP Organic Initiative provides financial and technical assistance for implementing many of the conservation practices that directly support NOP water quality compliance — making this an area where organic certification and conservation program participation naturally align.

Manure is one of the most valuable fertility inputs in certified organic systems — and one of the most significant water quality risk factors if not managed properly. Excess nutrients from manure applications, particularly nitrogen and phosphorus, can leach to groundwater or run off to surface water, causing water quality impairment.

NOP manure management requirements that directly protect water quality:

Application timing:

• Raw manure must be incorporated at least 90 days before harvest for crops not in contact with soil, and 120 days before harvest for crops in contact with soil (§ 205.203). These restrictions protect both food safety and reduce the risk of untreated manure reaching water bodies during runoff events.

Application rate management:

• NOP requires that nutrient applications not create deficiency OR excess — meaning over-application of manure that loads phosphorus or nitrogen beyond crop removal is a compliance risk, not just an environmental concern. Regular soil testing is the primary tool for demonstrating appropriate application rates.

Setback from waterways:

• Manure applications must not contribute to contamination of water resources. Maintaining setbacks from streams, ditches, tile inlets, and sinkholes is both an NOP compliance expectation and an NRCS EQIP practice requirement.

USDA NRCS Nutrient Management Practice (590):

NRCS provides financial assistance for developing formal nutrient management plans that define application rates, timing, and setbacks that protect water quality — directly supporting both NOP compliance and Clean Water Act goals.

Irrigation water quality is a critically important and often overlooked aspect of organic farm compliance. NOP regulations require that water used in organic production not introduce prohibited substances or contaminants that could compromise organic integrity — and irrigation water drawn from certain sources can carry exactly these risks.

Key irrigation water quality considerations:

Source water quality:

• Irrigation water should be tested for indicators of contamination, particularly if drawn from surface water sources (ponds, streams, irrigation canals) that may receive agricultural runoff containing pesticide residues, heavy metals, or pathogens

• Well water used for irrigation should be tested for nitrates, coliform bacteria, and chemical contamination

• Your certifier will typically ask about your irrigation water source in your OSP review

Proximity to prohibited substance sources:

• If your irrigation water source is downstream or downslope from conventional fields where prohibited substances are applied, there is a contamination risk that your OSP must address

• Riparian buffer strips help filter runoff before it reaches irrigation water sources

Overhead vs. drip irrigation and food safety:

• Overhead irrigation of crops with edible portions that contact the soil creates pathogen transfer pathways that interact with both NOP and FSMA food safety requirements

• Drip irrigation significantly reduces this risk for many crops

USDA NRCS Irrigation Water Management Practice (449):

NRCS provides financial assistance for irrigation system improvements that improve water use efficiency and protect water quality — eligible under EQIP for certified organic and transitioning producers.

Certified organic farms have a natural alignment with conservation practices that protect water quality — the prohibition on synthetic pesticides and synthetic fertilizers eliminates two of the largest sources of agricultural water quality impairment. But organic farms can still contribute to water quality issues through erosion, manure runoff, and poor irrigation management. The most effective protective practices:

Cover cropping:

Continuous live soil cover is one of the most powerful water quality tools available. Cover crop root systems hold soil and absorb excess soil moisture, dramatically reducing erosion and nutrient runoff from bare soils during the non-cropping period. USDA NRCS EQIP pays for cover crop establishment (Practice 340).

Riparian buffers and filter strips:

Vegetated buffer strips along streams, ditches, and drainage outlets intercept surface runoff before it reaches water bodies, filtering sediment, nutrients, and any manure runoff. NRCS funds riparian buffer establishment through EQIP (Practice 391) and the Conservation Reserve Program (CRP).

Contour farming and terracing:

On sloping land, farming on the contour rather than up-and-down slope dramatically reduces water velocity and erosion. Terracing provides more structural water flow management on steeper terrain. Both practices are eligible under EQIP.

Grassed waterways:

Vegetated channels that carry concentrated runoff safely from fields without causing erosion or carrying sediment to waterways. NRCS EQIP Practice 412.

Constructed wetlands and water control structures:

On farms with significant drainage infrastructure, constructed wetlands and controlled drainage can capture and filter runoff before discharge. NRCS provides both technical and financial assistance for these systems.

Improving soil organic matter is one of the most powerful long-term investments an organic producer can make — and its water quality benefits are substantial and durable.

How organic matter improves water quality:

1. Improved water infiltration:

Higher organic matter content improves soil aggregate stability and pore structure, allowing more rainfall to infiltrate rather than running off the surface. Each 1% increase in soil organic matter increases the soil's water-holding capacity by approximately 1.5 inches per foot of soil depth. More infiltration means less surface runoff carrying sediment and nutrients to waterways.

2. Reduced erosion:

Biologically active soils with good organic matter content have more stable aggregate structures that resist raindrop impact and surface flow erosion — the primary mechanism for sediment and nutrient delivery to surface water.

3. Nutrient retention:

Organic matter acts as a slow-release nutrient reservoir and a cation exchange site that holds nutrients in the soil rather than allowing them to leach to groundwater. Higher organic matter soils have greater capacity to retain nitrogen and phosphorus between crop demand periods.

4. Reduced nitrate leaching:

In high organic matter soils with strong biological activity, nitrogen cycling is more tightly controlled — microbial immobilization of nitrogen during non-cropping periods reduces nitrate leaching to groundwater.