Getting water to a point where it will do the least amount of damage to your home's plumbing usually takes a water conditioning system. Most of the complaints about water come from it being "hard," which means that it contains a certain level of calcium and magnesium. Hardness is measured by how much of those two elements are in each gallon; 1 to 3.5 grains, and your water is considered "slightly hard." Another complaint is water that has a bad taste to it.
A water conditioning system can help improve your water. There are actually several types of systems, and a recent article by AZCentral.com described a bit about what each one does to your water.
Water softening system:
"The main way of reducing water hardness is by installing an ion exchange water softener. It will remove the scale-forming calcium and magnesium, replacing them with sodium chloride or potassium chloride."
Water purification system:
"To improve the taste of Arizona water, consider reverse-osmosis drinking-water systems. These units fit under the kitchen sink and will supply water to a holding tank, and, in some cases, connect to a refrigerator.Water flows through a sediment filter, which removes large particulates, then goes through a carbon filter to remove organic material, chlorine and the bad taste."
Catalytic system:
"...a catalytic system will provide soft water without using sodium chloride or potassium chloride as water softeners do."