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    The residential stack

    System types side by side, using what sellers list. Missing data is labeled, not guessed.

    Listed figures come from sellers. Confirm current pricing at the seller. How we make money

    Under-sink RO

    Waterdrop G3P800 Tankless RO
    Format
    Under-sink RO
    Listed output
    800 GPD; fills a 6 oz cup in 5 s (manufacturer-listed)
    Filter interval
    G3-N1CF up to 6 mo / 550 gal, $29.99; G3-N3CB up to 12 mo / 1,100 gal, $29.99; G3P800-N2RO up to 24 mo / 2,200 gal, $139.99 (list prices, Oct 2026)
    Install
    Not listed by seller
    Seller-listed cert
    Waterdrop states: system certified by IAPMO R&T to NSF/ANSI 42, 53 and 58 for claims on its Performance Data Sheet, and to NSF/ANSI 372 for low lead (as listed by the seller)
    Price band
    $500 – $1,500
    Check today's price (referral link, opens in a new tab)

    ReferralEditor's referral. We may earn a commission; the seller fulfills the order. How we make money · Disclosure

    Softener / conditioner

    Format
    Not listed by seller
    Listed output
    Not listed by seller
    Filter interval
    Not listed by seller
    Install
    Not listed by seller
    Seller-listed cert
    Not listed by seller
    Price band
    Not listed by seller
    Seller listing unavailable

    ReferralSeller links are referrals; untracked brands show the review instead. How we make money · Disclosure

    Examples are the highest-scored product with an approved seller link in each review group, not a ranking of the type.

    Atmospheric water generators we cover

    • WaterVO Countertop Vapor OptimizerWaterVO Countertop Vapor OptimizerUp to about 2.5 gallons a day (manufacturer-reported); lower in drier or cooler air$1,499 (launch price)Read full review
    • WaterVO Floor Model Vapor OptimizerWaterVO Floor Model Vapor OptimizerRoughly 1.5–2.5 gallons a day in coastal Southern California (about 2.5–3.0 on humid summer days); 5.3 gallons a day manufacturer high-humidity rating at 86°F/80% RH$1,999 (launch price)Read full review
    • Spout AWGSpout AWGUp to 2.5 gal/day$1,495Read full review
    • Kara Pure AWGKara Pure AWG2.5 Gal/Day$3,800Read full review

    Independent seller. Hydrology University is the publisher and referral source, not the seller.