Now let me please introduce LeRoy Nosbaum, Itron's President and CEO.
LeRoy D. Nosbaum
Good afternoon, everyone. Thanks for joining today's call. I'll begin with some thoughts regarding Q1 results. Philip will add some comments on smart grid opportunities around the world. Steve will cover financial results in more detail, and then I'll return with some closing comments before we open up the questions.
So let's begin with some thoughts about the first quarter. Some explanation of results and what we are working to achieve at Itron. Revenue for the quarter was $572 million. On a constant currency basis, revenues were up about 4% from Q1 of last year, including up about 5% in Water, 5% in electricity and 1% in gas. Given the economy around the world, I am pleased with the revenue in Q1.
Gross margin for Energy is a bit complicated, but if you adjust for onetime warranty insurance claim recovery we received in Q1 of '11, Energy gross margin was up by 90 basis points. In Water, gross margin was up 30 basis points. Total gross margin was 32%. While I'm pleased with 32% for now, we still have a lot of work to do in reducing the cost of parts and materials and increasing the efficiency of our factories.
We are working on better parts and material purchasing and expect continued improvement throughout the year. We are continuing with our factory rationalization effort, which will help as the year progresses. We are working the necessary adjustments, driven by slowing of OpenWay activity in North America, including cost reductions which are planned and budgeted for later this year.
Our Q1 -- For Q1, our warranty expenses were at a more reasonable level than they have been in past quarters. We have some potential to see gross margin improve further, but we're also working to mitigate potential downward pressure in the second half of the year. With one quarter in the books, we are on track so far.