Water quality is not absolute. One person may judge a waterbody as being high quality, while someone with a different set of values may judge the same waterbody as being poor quality. For example, a lake with an abundance of aquatic macrophytes in the water may not be inviting for swimmers but may look like a good fishing spot to anglers.

Water quality guidelines for freshwaters have been developed by various regulatory and governmental agencies. For example, the Canadian Council of Resource and Environmental Ministers provides basic scientific information about the effects of water quality parameters in several categories, including raw water for drinking water supply, recreational water quality and aesthetics, support of freshwater aquatic life, agricultural uses, and industrial water supply.

SURFACE WATER CLASSIFICATION
Water quality guidelines developed by the Florida Department of Environmental Protection (FDEP) provide use standards (Florida Administrative Code 62.302.5.0). The FDEP guidelines provide different water quality standards for waterbodies in each of five classes that are defined by their respective designated uses as follows:

• Class I waters are for POTABLE WATER SUPPLIES;
• Class II waters are for SHELLFISH PROPOGATION OR HARVESTING;
• Class III waters are for RECREATION and PROPOGATION AND MAINTENANCE OF A HEALTHY, WELL-BALANCED POPULATION OF FISH AND WILDLIFE;
• Class IV waters are for AGRICULTURAL WATER SUPPLIES; and
• Class V waters are for NAVIGATION, UTILITY AND INDUSTRIAL USE.