A common layout is pump → pressure tank → coarse sediment as needed → iron/sulfur filter → softener → fine prefiltration if required → UV → house. Exact order can change with chemical feed, pH correction or specialty equipment.
Pressure tank comes early
Standard whole-house treatment is normally installed after the pressure tank so the equipment receives stable pressurized flow.
Iron treatment before softening
Dedicated iron removal upstream protects ion-exchange resin from heavy iron loading and lets the softener focus on hardness.
UV belongs near the end
UV performs best on already-treated clear water. Upstream sediment and chemistry control help the chamber receive water with fewer interfering particles and color.
Do not build the train without lab data
Bacteria, nitrate, arsenic, pH, iron, manganese and hardness can require different technologies. CDC recommends routine private-well testing and certified laboratory analysis.