Purewell K Series 1.5 Gallon Gravity System

The K Series 1.5 is the smallest serious gravity system we have looked at. The housing is 304 stainless rather than plastic, it includes the stand, and there is a water-level window in the side — a small thing that matters daily, because gravity systems are opaque by nature and you otherwise lift the lid to see how much is left.

Capacity is 1.5 gallons, which Purewell sizes for two to three people. Flow is rated up to 4 gallons an hour on two filters installed, so a full tank is roughly twenty minutes of drip. That is the honest cost of not having a pump: you trade speed for needing no power and no plumbing at all.

The filter economics are the strongest part. A box of two is rated for up to 6,000 gallons, and the maker's own footnote is that actual life depends on source water and usage. At that rating the per-gallon cost is very low, though it is a rating and not a measurement we made.

The system ships without filters chosen — you pick a 3-stage, a 3-stage with fluoride reduction, or a 3-stage that raises pH, and the price changes with the pick. Make sure you are comparing the configuration you actually want, because the system price and the filter price are separate.

What the page does not do is point to a certificate naming this 1.5-gallon model, and our own check of NSF's public listing was blocked, so HU has not verified certification for this model. Treat its model-specific certification as unverified.