Water Efficiency and Conservation Investment Act of 2009 - Amends the Internal Revenue Code to: (1) allow, through 2014, individual taxpayers a tax credit for 50% of the cost, up to $750 per year, of installing qualified water efficiency property in a residence; (2) allow building contractors, through 2014, a $1,500 tax credit for each qualified, new, water efficient home constructed and sold to a homeowner; (3) allow the issuance of tax-exempt water conservation bonds; and (4) exempt prepayments under a qualified electricity supply contract from tax-exempt bond arbitrage rules.