Municipal water arrives treated, disinfected and pressurised. A well, a river or a lake supplies none of those three, and a system designed for a tap will not simply work when pointed at one.
The load is different in kind, not only in amount
Surface water carries silt, organic matter and seasonal swings a municipal supply does not. Groundwater can carry iron, manganese and hardness at levels that foul a membrane quickly. Pre-treatment ahead of the membrane is not an optional refinement here; it is what decides whether the membrane lasts months or years.
Nothing supplies the pressure
A pump-free system works because a utility already pumped. Away from that, something has to. This is the reason the A95R exists in the KomiBright range as the one model with a 25W priming pump and a 12-24V supply, and the one rated for open sources such as a river or a lake. Every other system in the range is municipal-tap-only, no pump and no electricity.
Disinfection is now yours to think about
On a private supply there is no residual protecting the water between source and tap, and testing is the owner's responsibility rather than a utility's published report. Test before specifying, and test again seasonally — a source that was clean in February is not thereby clean in August.
