Dropkin goes live on Product Hunt tomorrow. Before it does, I'd like to hear what has actually worked for you, since habits are what decide whether any water tracker gets used.
The bet Dropkin makes: logging is the hard part, not remembering. So you save the bottle you already carry once, with its real size, and log it whole, half or a quarter in one tap, in ounces or liters. Reminders only arrive during the hours you choose, stay quiet when you're on pace and stop once you hit your goal. There's an Apple Watch app, widgets and Shortcuts, plus optional Apple Health sync. The full tracker is free, with no account and no ads, and it works offline.