You also want to drop a hose from an outside tap down the top of the well casing after pouring the bleach down to really circulate it through the whole casing.

You also want to drop a hose from an outside tap down the top of the well casing after pouring the bleach down to really circulate it through the whole casing. High concentration bleach is also better than household. Then once you’ve opened all your taps and gotten bleachy water out of each, close the taps and leave it in the lines for as long as you can. Days if possible