Water woes!

We have water in our basement. Back in the storage area....got a lot of our boxes wet. I think it's coming from our water heater, but our water heater was just replaced right before we moved in so it's only 3 years old. I called our plumber (I can't believe I have a plumber! Who I might add has been to our house 4 times in the past three years) and he suggested calling the folks that put the water heater in because he said it should be warrantied for 6 years. There was a sticker on the water heater w/ the name of the plumber who did it and his phone number....I'm waiting for him to call me back. UGH!