To a certain extent, it's not unusual to have a brick wall absorb a certain amount of moisture (and you're right, it's usually through the mortar). You may find that there might be slight separations between the mortar and some of the brick just because of settlement of the structure. You'll want to re-tuckpoint these so you don't get further damage from moisture in there during the freeze/thaw season, because that can REALLY blow open a hole.
My house is 100 years old and is brick through-and-through. Over the bottom course of brick (and over the window/door lintels) there are "weep outs" that wick away the moisture which may find its way inside the walls...pieces of rope that were imbedded in the mortar from inside the wall and run to the outside.
David, Dodgeman, Ron J....do they still do masonry like that today?
But if you're really having a bad leakage problem on a 1-year-old home, I'd be back in the builder's face lickety-spit. Could be the water's coming down the inside of the brick veneer from the top of improperly flashed windows and doors. Have you tried standing outside with a hose and generously spraying over these areas to see if that gives you same results?