At current one-time list prices, the three core G3P600 cartridges annualize to about $145 per year: roughly $60 for CF, $30 for CB and $55 for the RO membrane.
CF cost per year
G3-N1CF is $29.99 and is rated up to six months, producing about $59.98 per year on the nominal schedule.
CB cost per year
G3-N3CB is $29.99 and rated up to 12 months, or about $29.99 per year.
RO membrane cost per year
G3P600-RO is $109.99 and rated up to 24 months, equivalent to about $55 per year when annualized.
What can change the real number
Source-water quality, household volume, subscription discounts, promotions and optional MNR35 or ALK35 cartridges can move real ownership cost above or below the nominal figure.
How to verify fit before buying Waterdrop G3P600 Replacement Filter Cost per Year
Treat compatibility as a model-number decision, not a shape-matching exercise. Start with the appliance or system model label, then confirm the exact cartridge or replacement code listed by the manufacturer. Similar-looking filters can use different tabs, seals, RFID features or bypass interfaces, so a cartridge that appears to fit can still leak, restrict flow or fail to lock correctly.
For aftermarket replacements, separate physical compatibility from filtration performance. A seller can correctly state that a cartridge fits a refrigerator while the contaminant-reduction scope differs from the original filter. If lead, cysts, PFAS or another health-related claim matters, verify the exact replacement model in the current certification or performance documentation rather than assuming an OEM-equivalent claim set.
Compare recurring cost, availability and replacement risk
Replacement products should be evaluated over several service cycles. Multiply the current cartridge price by the realistic replacement frequency, add shipping, and check whether the same model is consistently stocked. A low first-purchase price is less useful if the cartridge becomes difficult to source or if replacement intervals are short.
Watch for vague phrases such as “uses certified media” or “tested to a standard.” Finished-product certification is stronger evidence than a statement about one component. For marketplace listings, clear manufacturer identity, exact model numbers, return policies and traceable certification reduce the risk of counterfeit-style or poorly fitting replacements.