I’ve seen it when a person has well water, then city water becomes available, they might still se the well for lawn irrigation, washing the car etc…
Well water for sure with pressure tank. Another smaller pressure tank on hot water.
Top horizontal unit may be a UV light. Whatever it is has bypass valves, which may be open but hard to tell. Wish picture was bit better resolution. Where does that cord go to when it reaches the floor.
In some areas around here (not this picture) they add a pump (you’d see it there) and pressure tank if you’re on public water but at the end of the line to augment pressure in the home.
Have seen that, but meter would be before the pump in that case one would think.
Some people in my area will maintain the well for use with their landscaping/gardening/animals/livestock etc., and only use the municipal water for the home.
Nice