Rule 806. Requirements or criteria of this part for the various types of public water supplies shall be based on the facilities which the public water supply is intended to serve. If the volume of water used or the type of facilities or number of units served by a public water supply changes in such a way as to cause a change in the classification of a public water supply, the public water supply shall meet requirements applicable to the new classification.
Mich. Admin. Code R. 325.10806