Whole-house water treatment systems, also known as Point-of-Entry (POE) systems, are designed to reduce and/or remove contaminants in the water which is coming into your household through the water main and intended for showering, taking baths, brushing teeth, washing clothes, and washing dishes. For the most part, municipalities do a fantastic job of meeting the minimum drinking water requirements for the regulated contaminants, especially considering the number of households they supply and finite budgets. However, municipalities can only realistically and economically do so much, and it is unrealistic to think that any public water supply would be able to completely remove all of the emerging contaminants, known or unknown, regulated or unregulated. This is the precise reason why whole-house water purification systems were developed, and there are two main types of systems which play different but very important roles.