Watts Premier OneFlow Plus Review

Why we chose it

We wanted to reduce hard-water scale and improve water quality without salt or electricity. The OneFlow Plus pairs a carbon block filter with scale-prevention media. It's a wait-and-see system: the real test is whether scale in pipes, faucets, toilets and the water heater gradually decreases.

Installation: tools, fittings and four hours

We installed it ourselves with a PEX crimping tool, clamps and a PEX cutter from a kit. The parts list was longer than expected: 6 elbows, 2 tees, 3 ball valves, 2 female threaded adapters, 2 PEX crimp fittings, two 5-foot lengths of 3/4-inch PEX, crimp clamps and mounting hardware. The threaded adapters for the 1-inch NPT connections were surprisingly hard to find: four local hardware stores didn't have them, and we ordered them online.

The whole job took about four hours, including fixing the wall bracket with 3-inch and 1.5-inch wood screws, measuring and cutting the PEX, and crimping every joint. The most nerve-wracking moment was cutting into the existing water line. Connecting to an existing PEX section rather than the building's copper pipe made it much easier.

First startup

After restoring pressure and checking every fitting: no leaks. After four hours of measuring, cutting and crimping, that was a relief. The bracket holds the unit firmly in place.

Results so far

It's too early to say how much scale it prevents; salt-free systems show their effect gradually, and water still tests hard because the minerals stay in the water. We'll watch pipes, faucets, toilets and the water heater over the coming months and update this review. We haven't recorded before-and-after measurements yet.

Verdict so far

The installation went well and finished leak-free, but it needs plumbing skills, the right tools and quite a few fittings, so it isn't a plug-and-play job. Cautiously optimistic; the real verdict comes after several months of use.