Water Efficiency Improvement Act of 2014 - Amends the Internal Revenue Code to allow a tax credit for 30% of amounts paid for certified WaterSense program property (defined as any plumbing fixture or fitting that has been tested and certified in accordance with the WaterSense program of the Environmental Protection Agency [EPA], a voluntary partnership program for protecting the water supply by using less water with water-efficient products, new homes, and services, or an analogous successor program). Limits the lifetime dollar amount of such credit to $2,000. Terminates such credit after 2015.