AQ-4100NSF-R replacement cartridge
The Aquasana AQ-4100NSF-R is the replacement filter cartridge for both the AQ-4100NSF and AQ-4105 systems. The cartridge contains the KDF-55 copper-zinc media and activated carbon stages in a single sealed unit. Price: $29-$35 per cartridge at aquasana.com, Amazon, Home Depot, and Whole Foods Market locations. Subscribe and save options at aquasana.com provide 10-20% discount on automatic repeat deliveries. Keep one spare cartridge on hand to avoid a gap in filtration at the end of each filter cycle.
Housing cap O-ring
The filter housing cap uses an O-ring that seals the cartridge chamber. Inspect and re-seat the O-ring at every cartridge replacement. If the housing cap drips at the cap-to-housing seam after replacement, the O-ring is displaced. The O-ring is a specific size -- contact Aquasana customer service at 1-866-662-6885 for the correct replacement O-ring part number. Aquasana will ship the O-ring at no charge if the housing is within the 1-year warranty period.
AQ-4105 spray head -- separate replacement
The AQ-4105 massaging spray head can be replaced independently of the filter housing. If the spray head fails while the filter housing is in good condition, purchase only the AQ-4105 head from Aquasana directly. Contact customer service at 1-866-662-6885 or shop aquasana.com for the current replacement head part number. The head threads onto the filter housing outlet using the same 1/2-inch NPT connection as the filter-to-arm connection.
Aquasana 1-year warranty
Aquasana covers the AQ-4100NSF and AQ-4105 hardware (filter housing, showerhead, and connections) under a 1-year warranty for defects in materials and workmanship. Contact Aquasana at 1-866-662-6885 with proof of purchase for warranty service. Aquasana offers a Healthy Home Trial for direct purchases -- a satisfaction guarantee that allows return within a defined period if the product does not meet expectations. Filter cartridge depletion is not a warranty claim -- it is normal consumable use.