We live in a townhome, and pay a flat fee for water usage, so washing dipes only costs us the electricity. DH calculated it out, and it costs us about $50/year. Considering the vast majority of my stash from DD1 is now in use on DD2, I know we are saving tons. That and my girls both have crazy sensitive skin, so I change them often and DD1 could never wear generic sposies at all without constant rashes, yeah. It's definitely a savings for us.
Rebecca, married to J (2007), DD1 Anna (11/09) and DD2 Ada born at home 7/12 DS Henry born at home 3/14