(a) Small discharges (less than or equal to five hundredths (0.05) MGD):

1. (1) The most stringent effluent limitations for oxygen demanding flows from small dischargers will be ten/fifteen milligrams per liter (10/15 mg/L) CBOD₅/TSS, with nutrient removal where appropriate, which is considered as best conventional treatment for dischargers in this flow range; and
2. (2) On a case-by-case basis, less stringent effluent limitations may be permitted if stream modeling shows that water quality standards will be maintained.

(b) Outstanding state resource waters.

1. (1) Outstanding state resource waters include all water bodies designated in the Arkansas Water Quality Standards, 8 CAR pt. 21, as:

   1. (A) Extraordinary resource waters;
   2. (B) Natural and scenic waterways; or
   3. (C) Ecologically sensitive water bodies.
2. (2) For extraordinary resource waters and natural and scenic waters, in no event shall the effluent limitations be greater than ten/fifteen milligrams per liter (10/15 mg/L) CBOD₅/TSS.
3. (3) For ecologically sensitive waterbodies, limitations shall be determined on a case-by-case basis to protect the specific species in the waterbody.

(c) Reservoirs/domestic water supply:

1. (1) In all cases, applicable water quality standards shall be met; and
2. (2) All oxygen demanding effluent flows that are discharged into any lake shall have effluent limitations of ten/fifteen milligrams per liter (10/15 mg/L) CBOD₅/TSS with nutrient removal as appropriate.

(d) Discharge of domestic wastewater to the Illinois River Basin:

1. (1) No permit for discharge of domestic wastewater into the Illinois River or its tributaries by the cities of Fayetteville, Springdale, Rogers, and Siloam Springs shall authorize more than one milligram per liter (1.0 mg/L) total phosphorus based on a monthly average; and
2. (2) Compliance with subdivision (d)(1) of this section shall be attained as soon as feasible, but no later than January 1, 2012.

(e) Discharge of domestic wastewater to the Osage Creek Basin, a tributary of the Kings River:

1. (1) No permit for discharge of domestic wastewater into Osage Creek or its tributaries by the City of Berryville shall authorize more than one milligram per liter (1.0 mg/L) total phosphorus based on a monthly average; and
2. (2) Compliance with subdivision (e)(1) of this section shall be attained as soon as feasible, but no later than January 1, 2012.

(f) Discharge of domestic wastewater to Little Sugar Creek Basin:

1. (1) No permit for discharge of domestic wastewater into Little Sugar Creek or its tributaries by the City of Bentonville shall authorize more than one milligram per liter (1.0 mg/L) total phosphorus based on a monthly average; and
2. (2) Compliance with subdivision (f)(1) of this section shall be attained as soon as feasible, but no later than January 1, 2012.

(g) Discharge of domestic wastewater to Spavinaw Creek Basin:

1. (1) No permit for discharge of domestic wastewater into Spavinaw Creek or its tributaries by the City of Decatur shall authorize more than one milligram per liter (1.0 mg/L) total phosphorus based on a monthly average; and
2. (2) Compliance with subdivision (g)(1) of this section shall be attained as soon as feasible, but no later than January 1, 2012.