Resistivity is a measure of how much resistance the water offers to the flow of current. Healthy water should have a resistivity of about 6,000. This means that it would offer a very high resistance to the current. Clean water will also have a high resistivity. As more and more substances are dissolved in water the resistivity of water drops. As the resistivity of water drops, it means the kidneys have to work overtime processing the contaminants and other substances from the water. MRET water has been shown to the resistivity value close to ideal.