Yes that is right.It is necessary to know whether you have the right kind of water.Water may not always be pure it can contain a lot of impurities that can cause sickness and water-borne diseases.To ensure water is safe, the right purification technology should be used.Yes water purifiers depend on the type of water you receive.Log onto http://www.waterconsumer.org and get your water tested and get suggestions for the right water purifier you need.