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This website publishes administrative rules on their effective dates, as designated by the adopting state agencies, colleges, and universities.

Rule 3745-1-37 | Water quality criteria for recreation use designations and aesthetic conditions.


[Comment: For dates of non-regulatory government publications, publications of recognized organizations and associations, federal rules and federal statutory provisions referenced in this rule, see rule 3745-1-03 of the Administrative Code.]

(A) General information.

The chemical-specific criteria listed in this rule apply as "Outside Mixing Zone" or "Inside Mixing Zone Maximum." For the purpose of setting water quality based effluent limits, the criteria which apply "Outside Mixing Zone" shall be met after the effluent and the receiving water are reasonably well mixed as provided in rules 3745-1-06 and 3745-2-05 of the Administrative Code. The criteria listed as "Inside Mixing Zone Maximum" shall be applicable as end-of-pipe maximum effluent limits or as criteria to be met within a short distance of the effluent pipe except as provided in rule 3745-2-08 of the Administrative Code.

(B) Aesthetic conditions.

(1) The water quality criteria for the protection against adverse aesthetic conditions, or site-specific modifications thereof, shall apply as follows:

(a) The "Inside Mixing Zone Maximum" and "Outside Mixing Zone Maximum" water quality criteria, or site-specific modifications thereof, shall apply to all water bodies.

(b) The "Drinking" water quality criteria shall apply to all water bodies within five hundred yards of drinking water intakes.

(2) For any pollutant for which it is demonstrated that a methodology or procedure cited in this chapter is not scientifically defensible, the director may apply an alternative methodology or procedure acceptable under 40 C.F.R. 131 when developing water quality criteria.

MBAS (foaming agents)Tmg/l--0.50--
Oil & greaseTmg/l--10b--

1 T= total.

2 mg/l = milligrams per liter (parts per million); g/l = micrograms per liter (parts per billion).

3 IMZM = inside mixing zone maximum; OMZM = outside mixing zone maximum.

a This criterion is based on the protection against organoleptic (taste or odor) effects.

b Surface waters shall be free from floating oils and shall at no time produce a visible sheen or color film. Levels of oils or petrochemicals in the sediment or on the banks of a watercourse which cause deleterious effects on the biota will not be permitted.

c Total phosphorus as P shall be limited to the extent necessary to prevent nuisance growths of algae, weeds, and slimes that result in a violation of the water quality criteria set forth in paragraph (E) of rule 3745-1-04 of the Administrative Code or, for public water supplies, that result in taste or odor problems. In areas where such nuisance growths exist, phosphorus discharges from point sources determined significant by the director shall not exceed a daily average of one milligram per liter as total P, or such stricter requirements as may be imposed by the director in accordance with the international joint commission (United States-Canada agreement).

(C) Recreation.

(1) The water quality criteria for the protection of recreational uses shall apply outside the mixing zone to all water bodies assigned a recreation use designation.

Recreation useE. coli (colony counts per 100 ml)
90-day geometric meanStatistical threshold value1
Bathing water126410a
Primary contact recreation126410
Secondary contact recreation10301030

1 These criteria shall not be exceeded in more than ten per cent of the samples taken during any ninety-day period. a A beach action value of 235 E. coli colony counts per 100 ml shall be used for the purpose of issuing beach and bathing water advisories.

a A beach action value of 235 E. coli colony counts per 100 ml shall be used for the purpose of issuing beach and bathing water advisories.

Supplemental Information

Authorized By: 6111.041
Amplifies: 6111.041
Five Year Review Date: 2/1/2023
Prior Effective Dates: 2/14/1978, 4/4/1985, 8/19/1985, 4/30/1987, 5/1/1990, 4/26/1997, 10/31/1997, 7/31/1998, 7/31/1999, 2/22/2002, 12/30/2002, 3/15/2010, 1/4/2016