Free Microbial Water Testing for Farmers

Photo from the Western Center for Food Safety

Are you a farmer who needs to conduct water testing on your farm? CAFF will cover the costs of microbiological water testing for your farm. This program lasts until funding runs out.  

Why does my farm need to test our water?

To ensure acceptable water quality and reduce on-farm food safety risks. Water can be a source of pathogens that spread to crops during pre-harvest, harvest or post-harvest practices. Annual water testing helps ensure that your water quality is maintained and identifies any increased risks that need to be addressed.

How do I get water tests for free?

Farmers in California can drop off their water samples to the closest BSK Associates lab location and have their water tested for total coliform and generic E. coli at no cost.

How should farmers collect their water samples?
  1. Pick up sterilized bottles, and if needed, an ice chest with blue ice, from the BSK lab near you. You can contact the lab at least 24 hours before you pick up your bottles and they can prepare the supplies for you. 
  2. Follow the Microbiology Sampling Guidelines for collecting water samples on your farm
  3. Refer to the General Sampling Guidelines for completing the Chain of Custody paperwork and transporting samples back to the lab
  4. Deliver samples to the laboratory as soon as possible, no later than 24 hours after sample collection
What microbial water tests can/should I get?

Good Agricultural Practices (GAPs) recommends that farmers conduct microbiological water testing at least annually.

  • For surface water sources (e.g., ponds, canals) GAPs recommends 3 tests throughout one year.
  • For groundwater sources (e.g., wells) GAPs recommends 1 test per year.
  • If your farm receives water from a municipal source, look for the municipality’s water test results online. If there are increased risks on your farm, municipal water sources can be tested on-farm once annually.
  • We recommend testing your production water (water used prior to harvest) for total coliform and generic E. Coli by Quantitray, which is available through BSK Associates. This test will provide a numeric value of total coliform and generic E. Coli in your water.
  • You can test water used at harvest or during postharvest using the method above, or you can test for total coliform and generic E. Coli by Colilert 18, which is available through BSK Associates. This test will provide a presence/absence result of total coliform and generic E. Coli in your water. 
Will I be reimbursed for the costs of water testing?

No, CAFF will pay for the water testing upfront. CAFF has a contract with the BSK Associates, so farmers participating in this program will need to provide the CAFF account information on their chain-of-custody (COC) form. Download the COC form with CAFF’s information here and drop off the form, complete with the required information, with your water sample(s).

Can I combine my water sample order with another farmer?

Yes! Farmers can combine orders with another farmer and drop off their orders together. To do this, follow the sampling instructions and submit samples collectively on one chain-of-custody.

How do I interpret my water test results?

It depends on your water source. Water used for pre-harvest (e.g., irrigation) should have less than or equal to 126 MPN of generic E. coli per 100 mL and water used for harvest or post-harvest should have less than 0 MPN of generic E. coli per 100 mL or no detectable generic E. coli per 100 mL. If your farm is covered under the Food Safety Modernization Act Produce Safety Rule (FSMA PSR), the law requires that water used for harvest or post-harvest must have less than 0 MPN of generic E. coli per 100 mL or no detectable generic E. coli per 100 mL. The FSMA PSR requirements for pre-harvest agricultural water have not been finalized. See this resource for more guidance about interpreting your water test results.

Is there someone at BSK or CAFF who can answer any questions related to this opportunity?

BSK Associates

Jaime LaFave, Project Manager at BSK Associates

P: 916.853.9293., ext. 145

C: 916.597.8207


Grace Perry, Organic Certification Specialist

C: 404.405.7933