I expected the remineralized water to taste obviously different, but the difference was subtle. For a rough side-by-side check, I poured one glass from the Viomi Master M1 and one glass of plain RO water from the system I had been using before the M1. I let both come to room temperature. I knew which glass was which, so this was not a blind test. At first, they tasted pretty similar. After a few sips from each, the M1 water seemed a little less flat and slightly fuller. I liked it better.

That was enough for me. I chose the mineral stage for taste, not because I expected a health benefit. I wanted RO water that tasted a little less neutral for everyday drinking.

I had three fairly different setups on my list. Bluevua ROPOT sits on the counter and sends the finished water to a carafe. Waterdrop X12 and the M1 install under the sink and use smart faucets. I didn't want to refill a countertop feed tank, so I crossed the Bluevua off. The X12 is rated at 1200 GPD and the M1 at 1000 GPD. I didn't need the extra rating, and I preferred the M1's incoming and final TDS display at the faucet.

The TDS display was the part I nearly misunderstood. The faucet shows incoming water and the finished water from the M1. That finished-water reading comes after the mineral stage, not directly after the RO membrane. Because the system adds selected dissolved minerals back after RO, a higher final TDS than I expected does not by itself mean the membrane is doing a worse job. The number also does not identify what is dissolved in the water or prove that it is safe, so I use it as a trend instead of a score.

I chose the M1 because I wanted an under-sink system that did not need refilling and I wanted to try remineralized water. After installation, I found that I preferred its slightly fuller taste to the plain RO sample. The change is modest, but it is the difference I cared about. For my kitchen, the under-sink format and mineral stage made more sense.

Viomi Master M1 taste review: I expected a bigger difference