These lists sort systems by the job they do in the home, not by brand. As read on October 14, 2026, Frizzlife's non-electric M800-Basic was $319.99 one-time, the lowest tankless price on these lists. Start from your utility's annual water quality report or a test of your well.
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Shop Waterdrop systems →Pick by job: tankless RO under the sink, countertop RO with no plumbing, or a whole-house filter at the main line. Waterdrop sells all three; pick iSpring for tank RO or AquaTru for a money-back guarantee.
Frizzlife's non-electric M800-Basic, $319.99, is the lowest price here. Pick Waterdrop's G3P800, $999.00, for IAPMO R&T certification to NSF/ANSI 42, 53 and 58 per Waterdrop, or iSpring's RO800G, $527.99, for less.
Waterdrop's Direct Connect WD-10UA, $58.99, works with your existing faucet. Aquasana's Claryum, $349.99, names NSF/ANSI 53 with P473; for reverse osmosis, iSpring's RCC7 tank system is $229.99.
Waterdrop's WHF2E-PC, $165.99, and Express Water's WH250SCS, $166.99, are the lowest prices here. Waterdrop's WHF3T-FG, $419.99, is for iron and manganese; pick Aquasana's Rhino, $1,998.00, for a 10-year warranty.
A renter who cannot drill does best with countertop RO or a pitcher. Waterdrop's K19-SFK, $349.00, needs no installation; AquaTru's Carafe, $375.00, adds a 30 Day Money Back Guarantee.