The DAO No. 90-34 is a revision of the water usage and classification or water quality criteria. Under the order is the water usage and classification of fresh surface waters, coastal and marine waters, the general provisions on water classification, the water quality criteria, the approved methods of analysis, as well as the significant parameters for selected types of industries. The order helps classify the varying bodies of water found in the Philippines. This is specially helpful with industries that would make use of bodies of water, such as the tourism industry or water services providers.