Fertilizers, animal wastes, and sewage systems should be located and managed so that they do not contaminate the well. If a nitrate source is too close to the well and cannot be moved, then you may need to consider having the well permanently sealed and replaced by a licensed well contractor. Home water treatment units are not recommended for treating high nitrate water which will be given to infants. There is no foolproof way of knowing when the treatment system may fail, and blue baby syndrome has been known to occur after just one day of exposure to high nitrate water. Private wells should be tested at least once a year for bacterial safety .
Spring is usually a good time to test.
It is also wise to test well water for bacteria any time the water changes in taste, odor, or appearance. In addition, water can absorb lead from old lead pipes, lead-soldered copper pipes, or brass plumbing components, when the water stands idle in the pipes for more than a few hours. Also, never use water from hot water faucets for drinking or cooking. Other contaminants sometimes occur in private water systems, but much less frequently than bacteria, nitrate, or lead. If the well is located close to fuel tanks or a commercial or industrial area, a test for volatile organic chemicals may be a good idea.