After 3 months, all of the sudden, no water came out.  We called a plumber and $150 later, he put 6 batteries in, and we had water! But no hot water! Called Delta and they are sending a new cartridge, which we will replace ourselves...hopefully we'll be able to do it and hopefully that solves the problem.  I don't think we should have to replace batteries after only 3 months!.  After questioning this, I have now ordered a power supply to keep plugged in, and battery pack will be the backup. Customer service was very helpful....too bad I had to call them though. Faucet looks beautiful and touch faucet is a good idea, but has too many things that go wrong.