Whole-House Water Filtration in Markham

Markham switched from free chlorine to chloramine for residual disinfection in 2004. Chloramine is more stable in distribution but harder to remove with standard granular activated carbon (GAC). Catalytic carbon (Calgon Centaur, Jacobi AquaSorb CX) has surface-modified active sites that catalytically reduce chloramine. Most cheap fridge/pitcher filters are GAC-only and underperform on chloramine.

Add up the simultaneous fixture demand (shower 2.5 GPM, toilet 1.6 GPM, kitchen sink 2.2 GPM, dishwasher 2.0 GPM). A 3-bath family of 4 typically needs 10–15 GPM peak. Pick a cartridge rated at ≥1.5x peak (so 15–22 GPM rated cartridge for that home). Undersizing creates pressure drop and shower-trickle complaints.

Sediment pre-filter every 3 months. Catalytic carbon main filter every 12 months on Markham Lake Ontario water (chloramine load is moderate). KDF-55 stage every 18–24 months. Set a calendar reminder; we e-mail homeowners on schedule. Replacement cartridges $80–$220 per set.

Only if undersized or clogged. A correctly-sized cartridge with ≥1.5x peak GPM rating produces under 5 PSI drop at full demand. If your shower trickled the moment the filter was installed, the cartridge GPM rating was too low — pick a larger housing or split into parallel housings. Backwashing systems eliminate this concern entirely.

Yes — strongly recommended at install. Lets you isolate the filter for cartridge changes without shutting off house water, and lets a plumber service the system without water-pressure surprises. Retrofitting a bypass after install is 3x the cost. Standard bypass tee + ball valves $80–$150 in parts; included in our quotes.