If hard water is a problem in your house, you might want to look into getting a water softener. The scale in your water can build up stubborn deposits in the plumbing, decreasing water flow and reducing the life of your appliances. A water-softening system uses tiny resin beads to attract and remove calcium and magnesium ions from the water. It's powered by the water's flow, so it won't add to your electric bill.
For more on plumbing, consider:
Radio: Water Filtration
8 Common Water Problems (and Their Cures)
Top Tips for Troubleshooting Low Water Pressure