Originally Posted by dellwear

Not that much but I do know that they waste about 90% of the water you put through them making them a little impractical if your on a water meter

Theres a good article here:

http://www.ext.nodak.edu/extpubs/h2o...m#disadvantage

Edit- Thinking about it an activated charcoal filter may remove Prozac from the water as it traps organic/complex molecules. Worth looking into as they should be a lot cheaper!