a) Facilities which meet the following conditions need not perform the analysis required by Section 373.304:

1. 1) The facility must be designed for a waste load less than 750 P.E., and
2. 2) The critical length of stream below the discharge is not subject to significant sediment oxygen demand from bottom deposits as described in Section 373.302(d).

b) After review of the application for smaller facilities the Agency shall require further stream study if warranted by local conditions including:

1. 1) the impact of other dischargers on the stream,
2. 2) the stream use designation or stream segment classification, or
3. 3) other characteristics that would limit the assimilative capacity of the stream.