Just my two cents to add to the body of knowledge, here. I base the following on direct experience: the possibility exists that a well/septic field separation could have been approved by the jurisdiction for less than the required separation distance if the casing had been sunk deeper than that normally required. Some jurisdictions allow it, some don’t. In my state, the waivers can be found on the actual well permit.
Also, look at FAC Rule 64E-8.003(1). I offer no interpretation, just one paragraph from the rule. This should be confirmed locally:
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[FONT=Times New Roman]64E-8.003 New Private and Multi-family Water System Construction.[/FONT]
****FONT=Times New Roman All potable wells serving private water systems and multi-family water systems shall be separated from major contaminant sources per subsection 64E-8.001(4) and subparagraphs 64E-8.002(2)(a), (b)1. and 3., F.A.C., and shall be constructed at least 75 feet from any OSTDS. Paragraph 64E-8.002(2)©, F.A.C., shall also apply to wells serving private and multi-family systems.[/FONT]
Link: https://www.flrules.org/gateway/ruleno.asp?id=64E-8.003