Pay attention to what's happening around your water source and its watershed. Watch for dead animals, contamination by human sewage, and chemical contamination.

Filter your water. Consider putting a filter/chlorinator system at the well head and installing purifiers on or before the faucets that will be used for drinking and cooking water. When it comes to filters, you generally get what you pay for. Expect to fork out some dollars for a good system and be aware that high-tech filtering systems require periodic filter replacement and water testing.