UV Water Filter - LED UV Water Purifier for Under Sink, Reduce up to 99.999% Bacteria, Maintenance-Free for Reverse Osmosis System with Instant Flow Sensor, Mercury-Free, 1GPM

Main thing for a spring is a spring box to cover the spring to keep animals and such from shitting in it. This will get your Total Dissolved Solids (TDS) down also from other organics getting in the water. You dont need reverse osmosis system, Just 2 filters and a sediment UV at the end. I use this brand for UV source. https://www.amazon.com/dp/B0FBQTM1Q6 And for a filter I use this for the filter canister https://www.amazon.com/dp/B07799BBST?