Water Protection Program
Water Quality Standards
Antidegradation
Antidegradation requirements are consistent with 40 Code of Federal Regulation 131.12 that outlines methods used to assess activities that may impact the integrity of a water and protect existing uses. This policy may compel the state to maintain a level of water quality above those mandated by criteria.
Antidegradation language in Missouri's rules are available on the Secretary of State's website at www.sos.mo.gov/adrules/csr/current/10csr/10c20-7.pdf, page 12, beginning middle of right-hand column. This rule references the May 7, 2008, Missouri Antidegradation Rule and Implementation Procedure.
Missouri Tiers in Summary:
Tier 1 - 10
CSR 20-7.031(2)(A)
For waters that just maintain a level of water
quality that protect public health and existing in-stream
water uses there will be no impairment or loss of existing
uses.
Tier 2 - 10
CSR 20-7.031(2)(B)
For waters that maintain a level of water
quality better than applicable water quality criteria. Existing
levels of water quality shall be fully maintained and protected
unless lowered water quality is necessary to allow important
economic and social development in the area.
Tier 3 - 10
CSR 20-7.031(2)(C)
There shall be no lowering of water quality
in outstanding state or national resource waters as designated
in Tables D and E.
Corresponding Rules at the Federal Level
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