We purchased the zero water bottle a few years back and it has made island living so much easier. You put the bottle on the cooler, fill the top with tap (lake) water and it runs through the built in filters and then the cooler operates as normal. No carrying 5 gallon bottles, no little plastic bottles to waste, it's a great device anywhere but on the island, it's even better.
And it comes with a water tester too.
https://www.zerowater.com/products-accessories