Water Use on Produce Farms: A Focus on Food Safety

From dwindling ground water supplies in the west to flooded fields around the country, water use on produce farms has certainly been in the news.  As part of UNH Extension’s on-farm water-related programming, we have been collaborating with growers to evaluate the safety of the water used during growing and handling activities. Water plays a crucial role in the farm environment and consequently has the potential to transport contaminants throughout the production system. The primary focus of this current work has been on assessing microbial risks since water contaminated with pathogens, such as Salmonella and E. coli O157:H7, has been implicated in recent foodborne illness outbreaks.

Water safety, like any aspect of farming, is a multifaceted issue. During these visits, we delve into various aspects of water management, including pond water maintenance, groundwater depth and surface water infiltration, human pathogen survival and die-off rates in the environment, animal sources of human pathogens, the pros and cons of anti-microbial pesticide management in produce wash water, pack shed water discharge practices, water sampling, UV light, and other water treatment options for managing pathogens, amongst others.

The visits have demonstrated that many New Hampshire growers are already using strategies to minimize the risk of produce being contaminated by water. Another piece of good news is that many of the practices which support public health, such as drip irrigation, also help to reduce water usage, manage plant diseases, and extend shelf life by minimizing postharvest spoilage losses.

Photo: Water being pulled from the Connecticut River to irrigate produce crops.

These water quality visits also aim to assist farmers in fulfilling the requirements mandated by the water section of the Food Safety Modernization Act (FSMA) Produce Safety Rule. The comprehensive set of water quality rules went into effect for large farms in April 2025 and will be gradually phased in for smaller farms over the next two years. While some growers in the state utilize a single water source to meet all of their irrigation and postharvest handling needs, others in New Hampshire rely on up to 15 water sources and may utilize a single source for multiple crops. Consequently, UNH Extension collaborated with growers to modify national-level record forms and create examples tailored to local farming conditions.  The remainder of this article provides an overview of the FSMA water-related requirements, resources, and records that growers can utilize to fulfill these requirements.

FSMA Produce Safety Rule Water Requirements

The New Hampshire Department of Agriculture, Markets and Food oversees the Food Safety Modernization Act (FSMA) Produce Safety Rule program in the state.  The Rule has a general requirement that all agricultural water used in growing, harvesting, packing and holding produce “must be safe and of adequate sanitary quality for its intended use”. It defines agricultural water as water that is intended to, or is likely to, contact any fresh produce subject to the rule, as well as any food contact surfaces.  Here are the detailed requirements broken down into three key areas:

1. Annual Inspection and Maintenance of all Agriculture Water Systems

Requirements: Inspect each agricultural water system to identify produce safety hazards found in the system - at the beginning of the growing season and at least once a year.  The system must also be monitored and maintained to prevent contamination. Requirements apply to both pre-harvest and post-harvest water use and the findings of the inspection must be documented.

Records: Utilize the New Hampshire Annual Agriculture Water Inspection Template to compile a list of your water systems and complete the required record documenting the inspection. This document provides an example of how to fill out the record (pg. 2) and guidelines for determining your inspection findings and maintaining your water system (pg. 3).

Resources: Here is a video (5 minutes) from MSU Extension showing how to conduct a water system inspection and the items that must be inspected and maintained.

2. Annual Pre-harvest Agriculture Water Assessment

Requirements: Make a determination of the water quality for each water system by completing a written Agricultural Water Assessment at least annually. This assessment is different from the inspection in that it is only required for water that contacts the harvestable portion of a crop during growing. The assessment includes evaluating five factors, using the factors to make a written determination of water safety risk, and then complete actions based on the risk determination. The factors included in the assessment are: water source and distribution system risks, water application method and timing, crop characteristics, environmental conditions, and other factors (such as water testing results).

Records: Use the New Hampshire Annual Pre-Harvest Agriculture Water Assessment Record to complete the assessment for each of water source. Growers can use the pond water and well water examples as a resource when completing the form.  Both examples are based on New Hampshire farm scenarios collected in Spring 2025.

Exemptions: An Agriculture Water Assessment is not required if Public Water Supply is the water source (documentation required), ground water has no detectable Generic E. coli (Testing results required), or agriculture water is treated (documentation required). 

Resources: Here are links to FDA Fact Sheets providing an overview of the assessment and risk-based outcomes and factors to consider during the assessment.  Here is a link to the  Produce Safety Alliance’s Fact Sheet describing the difference between the Annual Inspection and the Annual Agriculture Water Assessment.

3. Harvest and Post-harvest Water Requirements

Requirements: Water used in harvest and post-harvest activities (produce cooling or rinsing, cleaning or sanitizing of food contact surfaces, handwashing, ice making, or any other direct contact with produce or food contact surfaces) must meet the following standards:

• Untreated ground water – test for generic E. coli 4 or more times during the growing season or over the period of a year (no detectable generic E. coli allowed). Take 1 or more tests per year after initial year (if initial tests all meet requirement).
• Public water supply – obtain copy of test results or compliance certificate from municipality.
• Untreated surface water cannot be used for postharvest activities.
• Treated water must follow treatment guidelines in 21 CFR112.46

Growers must have a plan for maintaining and monitoring the quality of recirculated and batch water.

Resources: The Harvest and Post-Harvest Agriculture Water Testing for New Hampshire Farms includes water sampling locations and information on sampling procedures.

Records: The records required for post-harvest water are:

• results of water tests if using untreated ground water,
• compliance certificate if using municipal water,
• sanitizer treatment and water management monitoring logs, if using sanitizer, or
• treatment records if treating ground or surface water (record type depends on treatment type).

For More Information

Contact Wendy Johnecheck, Associate Extension State Specialist/Professor, Food Safety at wendy.johnecheck@unh.edu and (781) 521-6897 for questions about UNH Extension’s on-farm water programs and the FSMA Produce Safety Rule Water Requirements.

This work is supported by a grant from the New Hampshire Department of Agriculture, Markets and Food and the Food and Drug Administration (FDA) of the U.S. Department of Health and Human Services (HHS). The contents are those of the author and do not necessarily represent the official views of, nor an endorsement, by FDA/HHS, or the U.S. Government.