Agricultural Water FAQs - What rose to the surface

Recently, the FDA posted additional frequently asked questions related to Subpart E – Agricultural Water of the FSMA Produce Safety Rule. We took a deep dive into the ones that stood out to us. For the curious and for those with lots of extra time, there are 53 in total now to read on the FDA's website. The comments below reference the numbered list here (as of October 6, 2025): https://www.fda.gov/food/food-safety-modernization-act-fsma/frequently-asked-questions-agricultural-water-requirements-under-fsma-produce-safety-rule

For anyone who has followed the evolution of Subpart E or is familiar with the preamble to the final rule, these FAQs are not much more insightful. If you haven’t read the preamble to the rule, then some of the FAQs and highlights below might be useful to your understanding of the topic. 

If you decide not to read further, I would break down this piece of the regulation and FAQs into three main takeaways and reminders:

1. Testing cannot be relied upon as the sole means for decision-making for agricultural water use. Even if you are testing, the agricultural water assessment must still evaluate the greater environment and potential hazards to the water source. This transition from the 2015 proposed rule which relied heavily on testing metrics for decisionmaking is meant to provide a more holistic approach. See the “Testing as part of an assessment” section - #29-31 & #41.

2. There is a difference between the agricultural water assessment and the agricultural water system inspection. This Produce Safety Alliance fact sheet does a fantastic job describing the two and how they are not necessarily interchangeable, though there may be bits of information that are used to inform both. This is an important distinction, because in the event of an inspection, you’ll see that the records and requirements differ. See #6-15 & #52.

3. Growers must support their agricultural water assessment with “scientifically valid” information. This is likely to be a challenge for growers, large and small. Of course, if the farm has scientifically valid data or information from their own operation, that can be utilized; but most don’t. In addition, there is not (yet) scientific information to support every commodity, growing region, or environmental condition, nor can we expect that all growers will have the time, knowledge, expertise, and access to publications that leverage peer reviewed scientific information. For this reason, we encourage growers to work with local Extension professionals in your region, Associations, Center for Produce Safety, or other qualified food safety professionals (like Food Safety Strategy!) to help gather this information and evaluate how it can support the agricultural water assessment for your operation.

FAQ Takeaways

Numbered in reference to this website.

• #4 & #5 Take note of FDA’s interpretation of adjacent vs. nearby. You’ll see this language pop up quite frequently in this part of the rule because there are certain expectations FDA has if you have control over a hazard vs. the hazard being beyond your immediate control (in which case, they’ll expect to see other measures you’ve taken to reduce risks). This language also appears in many outbreak investigation reports, so it’s a good one to file away in your brain for how FDA views the two terms. 

• #7 You should be aware there is an ag water system inspection required by the rule. Are you expected to inspect portions of the water system not under your control? The answer is No, but it will influence how you identify and characterize the hazards. 

• #12 This one builds on #7. How can you assess potential hazards to the water NOT under your control? FDA lists a few potential sources of information you might consider (e.g., Extension, associations, irrigation district managers) that can help inform what might be happening regionally or upstream if you are using a shared water source. 

• #14 There are certain exemptions from having to do the ag water assessment – such as if you’re using water from a municipal water source that is delivered in a closed distribution system to the crop that allows quality to be maintained. However, if the municipal water is conveyed to the farm and then enters an open irrigation canal which could be influenced by other sources of contamination, the exemption no longer stands and you’d need to conduct an ag water assessment. 

• #17 Following on #14, if the water system has both closed and open elements for distribution, you must consider the individual properties of each component in the ag water assessment (e.g., detail potential hazards to an open canal vs. how hazards are managed in the closed distribution portion, such as through installation of backflow prevention devices).

• #18 & 19 Both use an example of traffic patterns in relation to the water source, particularly for vehicles containing animal waste – perhaps this was an observation in the past by an inspector? In any case, think about where vehicles (farm or regular civilian traffic) travel and how things like dust and other sources of contamination from vehicles passing by can pose. 

• #21 Beyond the obvious sources of contamination like BSAAO and human feces (e.g., sewage) – there is also expectation that growers will assess the “degree of protection” of a water source and if applicable to the farm, consider things like upstream maintenance, urban development, and human activities (like RV parks or water recreation) in their ag water assessment. 

• #23 I think this one has been a frustrating one for growers to wrap their heads around since such little data for every crop currently exists. But essentially, FDA expects you to evaluate crop characteristics. Some examples are provided here: like netted cantaloupe or surface area of leafy greens, the growth characteristics that make the crop susceptible to splash from rain and soil, or physical damage from weather events (like epidermal peel and hail). No resources are specified to help bring awareness to these characteristics that may make a crop more susceptible, but we encourage you to leverage information from organizations like the Center for Produce Safety, Extension, or us to help! And by the way, #24 that follows notes that FDA doesn’t expect you to do an assessment for every commodity, but characterizing commodity groups could be acceptable (e.g., characterizing citrus, leafy greens). 

• #25 & 26 Though FDA says they are not expecting a complex analysis of weather/environmental conditions (e.g., installation of a weather station is the example used) for the ag water assessment, the environmental condition guidance still lacks practical and accessible information for growers on how to assess these risks – i.e., from die-off of pathogens due to environmental conditions. While growers, especially those who have been growing on the land for a number of years, have a keen understanding of weather trends, many do not have degrees in microbiology that would enable them to understand die-off kinetics of human pathogens given a variety of environmental conditions. This is one place it might be helpful to bring in expertise to help you assess the “normal” conditions in your growing region, taking into consideration the crop and potential hazards that exist.  

• #28 FDA does give insight to what they think are examples of “significant changes” requiring a reassessment of the water system. One example provided is if a new dairy production operation starts up next door to a growing area. This would warrant a reassessment of the water quality. 

• #29 IF testing as part of the assessment, growers have the flexibility to use any sampling frequency and microbial criterion that is “scientifically valid” and meets 112.43(d)(3). However, if they have scientifically valid data or information that is more reflective of the unique water conditions than the approach proposed in the 2015 PSR, then the grower must use that information. I read this to say, use the most recent and relevant data you have for the water source, even if you have lots of historical data (which can be helpful too). 

• #30 Even if you are testing, testing is NOT the sole determinant of whether corrective actions or mitigation measures are necessary. 

• #33 Many growers don’t realize there is a difference between corrective actions and mitigation measures provided in the rule. Corrective actions are for immediate public health risks whereas mitigation measures provide more flexibility in the timing and implementation of actions to manage the risk. Additionally, corrective actions require that you immediately stop using the water until corrective measures are implemented. This could be important in the way you document your ag water management decisions during an inspection. 

• #41 Gives insight to what FDA considers appropriate to determine the effectiveness of any corrective actions or mitigation measures you may take. FDA re-emphasizes here that farms must not rely on test results alone in making decisions around the safe use of their agricultural water.

• #43 While FDA does still reference the 2015 standards for microbial die-off (0.5 log/d for up to 4 days), there are a few approaches outlined as appropriate. If a farm decides not to test pre-harvest water, they are allowed to rely on an increased application interval at a minimum of 4 days between application and harvest. A word of caution about this approach though – as many factors could affect whether die-off of pathogens does occur. For example, weather (high or low UV index, relative humidity, rain events) or starting concentration of organisms in the water.  Don’t just blindly use 4 days and call it good. 

• #44 Also a word of caution on the use of mitigation measures during post-harvest activities such as washing and storage. It is well known that “washing” is not going to eliminate the pathogens, if present, from the produce. Though some log reductions may be achieved, the outcome will be highly dependent on the incoming load from the product, the water quality parameters of the water (such as pH, turbidity, etc.), type of sanitizer used and overall wash system functionality. You’re better off focusing on minimizing the pathogens from getting onto the produce in the first place, then to rely on a post-harvest water “treatment” to reduce the risk. 

• #47 Reminder – if you do decide to treat pre-harvest water with a chemical treatment (i.e., sanitizer or antimicrobial compound), you must use the product for its specifically registered uses only. There are products on the market that have historically been used for bacteria or algae control in irrigation systems, but they are NOT labeled for use against human pathogens. If you aren’t sure where to find a sanitizer labeled for your specific use – check out this great tool from the Produce Safety Alliance. You can sort by product, active ingredient, labeled uses, organic certification, and more. 

• #48 While treating pre-harvest water can be a good option, it’s not just as simple as adding sanitizer to the water and calling it good. FDA specifically calls out that other water quality parameters and monitoring that need to be conducted to ensure the sanitizer is effective. You can expect that an inspector might ask to see recordkeeping to support your treatment process, beyond just what the level of sanitizer was in the water. 

• #49 Hey, don’t forget you can use publicly available data sets too! If your water source is tested by a third party and adequately represents the quality of water used during the farm’s growing season, by all means, use it. Just be sure that other factors that could impact the water quality, such as impacts along the distribution system from the source, are accounted for!

• #50 This is not new, but if you are looking for the list of acceptable test methods, here they are.

• #52 Let me reiterate here that the ag water inspection and ag water assessment are two different things. FDA will expect you to have evaluated a much wider set of information for the water assessment. Check out the PSA fact sheet again if you need help distinguishing what’s required for the two components of Subpart E. 

• #53 In the rule, there are multiple places where FDA states that the approach must be based on “scientifically valid” data. Most growers don’t have access to databases containing peer reviewed literature (though many are now open source). Reach out to your local Extension contact, association, or Food Safety Strategy if you need help locating the literature you need to support your practices. Don’t forget, you can use your own data and findings too!

Do these FAQs leave you feeling more like you’re treading water than using smooth strokes to get to the finish line on managing agricultural water safety and quality? Reach out to us! We’d love to dive into the deep end with you. Pooling our knowledge can get you flowing in the right direction. Contact me directly for more eye rolling water puns.