Well, I had to get a system, and I got a Pur filter that attaches to the faucet. The first filter cartridge lasted 4 months before requiring a new one- $20. It does the job just fine, and despite being attached to the faucet, never really gets in my way. I think I paid 30 bucks for the housing, which came with a filter cartridge, and installed it in 5 minutes. There may be better ways to do it, but this has worked just fine for me.