Single-use long-life faucet mounted water filtration devices are disclosed. A bathroom water filtration device having two outlets for filtered water is disclosed. Additionally, a fountain head is included for use in the bathroom water filtration device. The water filtration device is of unibody construction formed by ultrasonically welding certain parts thereof together. Since the devices disclosed are disposable, no filter replacement or other maintenance is performed. A gate, magnet(s), sensor and electronics provide an indication of filter performance enabling disposal of the water filtration device and installation of a new device. A kitchen water filtration device is larger than the bathroom device. Both the kitchen and bathroom water filtration devices are small and are mounted behind the faucet connection so as to facilitate full utilization of the sink or wash basin.