All surface waters in Iowa are classified for protection of general uses. In addition, many waters are also classified for designated uses. Surface waters classified for designated uses maintain flow throughout the year or contain sufficient pooled areas during intermittent flow periods to maintain a viable aquatic community.

• Primary contact recreational use (Class “A1”): Waters in which recreational or other uses may result in prolonged and direct contact with the water, involving considerable risk of ingesting water in quantities sufficient to pose a health hazard. Such activities would include, but not be limited to, swimming, diving, water skiing, and water contact recreational canoeing.
  
  
  
  
• Secondary contact recreational use (Class “A2”): Water is which recreational or other uses may result in contact with the water that is either incidental or accidental. During the recreational use, the probability of ingesting appreciable quantities of water is minimal. Class A2 uses include fishing, commercial and recreational boating, any limited contact incidental to shoreline activities and activities in which users do not swim or float in the water body while on a boating acivity.
  
  
• Children’s recreational use (Class “A3”): Waters in which recreational uses by children are common. Class A3 waters are water bodies having definite banks and bed with visible evidence of the flow or occurrence of water. This type of use would primarily occur in urban or residential areas.
  
  
• Aquatic life use: uses of waters by fish, aquatic and semiaquatic species and wildlife. Surface waters in Iowa designated for aquatic life uses are termed Class "B" waters for which there are four different designated aquatic life uses. The Class B uses are protected by criteria for dissolved oxygen, pH, temperature, ammonia, toxic metals, toxic organic and inorganic compounds, and heat.
  
  
  
• Drinking water use: surface waters that are used as a raw water source of a potable water supply. Surface waters in Iowa designated for drinking water use are termed Class "C" waters. The Class "C" uses are protected by criteria for radioactive substances, pH, pesticides, toxic metals, toxic organic and inorganic compounds.
  
  
• High Quality: Some surface waters with unique physical, biological or chemical features are also designated in one of two "High Quality" type of uses. Waters designated as High Quality (HQ) receive additional protection for their unique physical, biological and chemical features present. HQ waters have exceptional recreational and ecological importance. Waters designated as High Quality Resource (HQR) receive additional protection for their unique physical, biological features, but the chemical integrity will be maintained to the numerical criteria noted in the Water Quality Standards. HQR waters posses unusual, outstanding or unique characteristics that enhance the beneficial uses and warrant special protection. HQ and HQR waters are specifically protected in the antidegradation policy.

• A discussion of the Water Quality Criteria that protect the designated uses.
• A discussion of the antidegradation policy. (*.pdf file)