Whole House Water Filter | 4 Stage | UV

The 4-stage upgrade of the 3-stage whole-house filter and UV system — same Big Blue 20" × 4.5" housings, same 254 nm UV-C disinfection chamber, with an additional carbon stage for longer chlorine-reduction service intervals and finer chemical polishing before the water enters the UV chamber.

Why 4 Stages Over 3

A 3-stage UV system handles sediment, basic carbon polishing, and UV disinfection. Where the 3-stage version puts the carbon work on a single cartridge, this 4-stage build splits that work across two distinct carbon stages: one bulk-reduction granular activated carbon stage and one polish carbon block. Three practical effects:

• The carbon stages share the chlorine and chemical adsorption load, so each stage lasts longer between replacements
• Better chemical reduction in the finished water reaching the UV chamber — cleaner water means more effective UV pathogen kill
• Less risk of chemical breakthrough during the back-half of the cartridge service cycle

For properties with heavier chlorine loads, persistent taste/odour issues, or installations where missing a service interval is likely, the 4-stage build buys real margin over the 3-stage equivalent.

Four-Stage Configuration

• Stage 1 — Sediment filtration: removes silt, dirt, and rust from the incoming water
• Stage 2 — Granular activated carbon (GAC): bulk reduction of chlorine and organic contaminants
• Stage 3 — Carbon block polish: finer chemical polishing and additional chlorine adsorption
• Stage 4 — UV disinfection chamber: 254 nm UV-C germicidal lamp

Maintenance

Replace the UV lamp every 12 months. Cartridges every 6–12 months depending on incoming water quality. The same UV-maintenance discipline applies as for the 3-stage system: a degraded UV lamp or fouled quartz sleeve compromises pathogen kill even with healthy lamp glow, so calendar-based replacement matters.

Installation and Power

Professional installation recommended. The system requires a 240 V mains connection at the install point and connects to the cold supply line at the point of entry. A licensed plumber and a basic electrical connection are needed for compliant installation.