We have a two story home and the water has been fine for all 30 years we have lived there. After being away from home for a week, warm water started coming out of the cold water faucets in all bathrooms, both upstairs and downstairs. I'm afraid it's a sign my water heater will burst? Also, we've been running out of hot water during showers. I'm a good do-it-yourself'er but this one stumps me. Any suggestions?