How to Disinfect Wells
The protocol listed in the pdf attachment here explains an inexpensive and relatively simple process to follow. This information comes courtesy of Delavalle Laboratory, Inc, a regional environmental/agricultural laboratory.
Note: The telephone numbers at the bottom of the document listing who to contact for additional assistance are for Fresno County. You’ll need to contact similar offices in your own county, if you live elsewhere.
It is assumed that the procedure described in the link above would be permissible for organic growers, as well as conventional growers, because the bleach would be sufficiently diluted to meet the maximum residual disinfectant levels specified in the Safe Drinking Water Act (currently 4 ppm, expressed as chlorine).
For more information regarding organic food rules on chlorine, download the free publication: Making Sense of Rules Governing Chlorine Contact in Postharvest Handling of Organic Produce, written by UCCE Postharvest Handling Specialist Trevor Suslow.