Choose a UV system with validated flow above the home’s realistic peak demand at the relevant dose condition. VIQUA’s current Arros line includes 9, 15 and 22 GPM classes for different whole-home demands.
Flow rate is tied to dose
A UV system should be evaluated at its validated treatment flow, not merely by chamber size or lamp wattage.
9 GPM class
VIQUA Arros 9 is rated 9 GPM and fits smaller residential demand when peak flow stays below that range.
15 GPM class
Arros 15 is rated 15 GPM and provides more margin for larger households or overlapping fixture use.
Pretreatment protects UV performance
Sediment, color and other water-quality issues can interfere with UV delivery. Whole-home UV is normally placed after upstream filtration so the chamber receives clearer water.
Testing and treatment order for UV Water System Flow-Rate Sizing: 9 vs 15 vs 22 GPM
Private-well treatment should start with measured water chemistry. Iron, manganese, hardness, pH, sulfur and sediment can interact, and bacterial concerns require a different treatment step from aesthetic staining or odor. A symptom can point toward a likely cause, but it is not a substitute for a source-appropriate laboratory or field test when equipment selection depends on concentration.
Treatment order matters because each stage protects the next. Coarse sediment is generally removed before media tanks, iron or sulfur oxidation is commonly handled before a softener when loading is meaningful, and UV disinfection is most reliable after upstream treatment has reduced turbidity and interfering material. The correct train depends on the actual chemistry rather than a one-size-fits-all diagram.
Size for service flow and backwash—not only household count
Whole-house equipment has to treat water at the rate the home actually uses during peak demand. Add simultaneous showers, laundry and fixtures, then compare that demand with the system's continuous service-flow rating. A treatment tank can remove the target contaminant in a laboratory and still be the wrong size if it causes a noticeable pressure drop in the home.
Backwashing systems also need enough pump capacity to clean the media bed. Oversizing a tank can create its own problem when the well pump cannot deliver the required backwash flow. Check both service flow and regeneration requirements before buying, and include ongoing media, chemical, electricity and maintenance costs in the decision.