Agricultural Water

Agricultural water can be divided into two groups: production water and postharvest water.

Production water: Any water that is used during growing activities. Production water use includes irrigation, fertigation, crop sprays, cooling, frost protection, and dust abatement.

Postharvest water: Any water that is used during and after harvest, including during packing and holding activities. Postharvest water use includes rinsing/washing, commodity movement, cooling, ice making, postharvest fungicide and wax, handwashing, cleaning and sanitizing.

Agricultural water from different water sources inherently carry different levels of risk.

Public water supply: Water from public water supplies has been treated and monitored by the public water utility and therefore has the lowest risk of being contaminated.

Ground water: Ground water, or well water, is generally less likely than surface water to be contaminated. The potential for well heads to be installed incorrectly and for contamination of ground water from septic tanks puts ground water at a slightly higher risk of contamination than a public water supply.

Surface water: Surface water, including rivers, streams, lakes, ponds, man-made reservoirs, and any other water source that is open to the environment, is the most risky agricultural water. Water quality from surface water can vary greatly between sites and over time. Some major contamination risks include wildlife, water runoff from upstream livestock operations, and wastewater discharge.

General Recommendations for Managing Production Water

Test your water. It is important to know the microbial quality of your water, both at the water source and at the output. While public water is tested and treated accordingly by the public water utility, it is still important to test public water from your faucets/hoses/etc. For information on how to collect and where to send water samples, and what test to order, see relevant questions under the heading "General FSMA Water Requirements" below.
Make a water distribution map. Map your water sources, permanent fixtures (wells, holding tanks, valves, etc) in your water distribution system, and the flow of the system. Include the following for each water source: the extent of your control, the degree of protection, the use of adjacent, nearby, and upstream land, the likelihood of contamination before water from each source reaches your farm. This allows you to identify risks in your water system and plan accordingly.
Think about your water usage and make changes to lower your risk. Keep potentially risky water (usually surface water) from contacting the harvestable portion of any crop. In general, the less contact produce has with water, the lower risk it has of becoming contaminated. For example, this may mean switching from overhead irrigation to drip irrigation in some crops. See below for some relevant fact sheets.

General Recommendations for Postharvest Water

Remember that all postharvest water, including water for produce washing and cooling, handwashing, ice-making, and cleaning and sanitizing of food contact surfaces needs to be done with potable water (water with no generic E. coli).
Test your water if you use ground water as your postharvest water source, or obtain the testing certificate for municipal water. All water used post-harvest should be potable (with no generic E. coli) when it leaves the tap. Untreated surface water should not be used for any postharvest activities. For information on how to collect and where to send water samples, and what test to order, see relevant questions under the heading "General FSMA Water Requirements" below.
Think about your water usage and make changes to lower your risk. For produce washing, single-pass water (e.g. spray from a hose, conveyer, or barrel washer) is less risky than recirculated or batch water (e.g., from a recirculating conveyor or dunk tank). Recirculating water can become contaminated and present a cross-contamination risk, and must be maintained to be of adequate quality.
Consider including a sanitizer in produce wash water. Sanitizers can help reduce the risk of cross-contamination in recirculated water and can help reduce the build-up of microbes and biofilms in single pass systems. Be aware, though, that sanitizers are pesticides (they kill microbes) and must be labeled for their intended use and handled and monitored carefully. The Produce Safety Alliance has compiled a list of sanitizers that are labeled for use on produce and food contact surfaces; see the resources and video tutorial below for more information.