I'm such a seltzer addict that I can pound through a two-liter bottle on my own in a day. The SodaStream, an ingenious countertop carbonator, turns tap water into sparkling water, housed in BPA-free, reusable plastic bottles — instant thirst-quenching with no landfill guilt. The best part is that you can adjust the carbonation levels: make your water tickle with the gentlest fizz, or sting the nostrils with beady bubbles.