Ag Order 4.0 requires well owners/operators to annually sample all on-farm domestic wells for Nitrate and 1,2,3-Trichloropropane (123-TCP).  Any users of the on-farm domestic wells must be provided with a summary of the laboratory testing results and information regarding health risks within three (3) business days of the operator or landowner receiving results from the laboratory. 

To provide the required notice to users of on-farm domestic wells, the well operator or landowner must use the notification form posted by the Central Coast Water Board (see links below).  Any alternative templates must be approved by the Executive Officer of the Water Board.  The notification is required for all on-farm domestic wells, regardless of whether or not the results showed exceedances of water quality objectives.

The MCL (Maximum Contaminant Level) for Nitrate measured as N (nitrogen) is 10 mg/L.  (Laboratory results that report nitrate “as nitrate” or “as NO3” should be compared to a drinking water standard of 45 mg/L.  For Preservation, Inc’s members in 2022, all lab results are being reported “as nitrogen” or “as N,” which has an MCL of 10 mg/L.)

The MCL for 1,2,3-TCP is 0.005 micrograms per liter (ug/L), which can also be expressed as 5 nanograms per liter (ng/L, or parts per trillion).