(1) Any NPDES permit issued by the council shall apply and insure compliance with all of the following, whenever applicable:

(a) All known, available, and reasonable methods of treatment; including effluent limitations established under sections 301, 302, 306, and 307 of the act. The effluent limitations shall not be less stringent than those based upon the treatment facility design efficiency contained in approved engineering plans and reports or approved revisions thereto. The effluent limitations shall reflect any seasonal variation in industrial loading;

(b) Any more stringent limitation, including those:

(i) Necessary to meet water quality standards, treatment standards or schedules of compliance established pursuant to any state law or regulation under authority preserved to the state by section 510 of the act; or

(ii) Necessary to meet any applicable federal law or regulation other than the act or regulations thereunder; or

(iii) Required to implement any applicable water quality standards; such limitations to include any legally applicable requirements necessary to implement total maximum daily loads established pursuant to section 303(d) and incorporated in the continuing planning process approved under section 303(e) of the act and any regulations and guidelines issued pursuant thereto;

(iv) Prevent or control pollutant discharges from facility site runoff, spillage or leaks, sludge or waste disposal, or materials handling or storage; and

(v) Meet the permit by rule provisions of the state dangerous waste regulation, WAC 173-303-802 (4) or (5).

(c) Any more stringent legal applicable requirements necessary to comply with a plan approved pursuant to section 208(d) of the act; and

(d) Prior to promulgation by the administrator of applicable effluent standards and limitations pursuant to sections 301, 302, 306 and 307 of the act, such conditions as the council determines are necessary to carry out the provisions of the act.

(2) In any case where an issued NPDES permit applies the effluent standards and limitations described in paragraph 1 of this section, the council shall make a finding that any discharge authorized by the permit will not have reasonable potential to violate applicable water quality standards and will have prepared some explicit verification of that finding.

(3) In the application of effluent standards and limitations, water quality standards and other legally applicable requirements pursuant to subsections (1) and (2) of this section, each issued NPDES permit shall specify:

(a) Average and maximum daily quantitative or other appropriate limitations for the level of pollutants in the authorized discharge. The average and maximum daily quantities must be made by weight except where the parameters are such that other measures are appropriate;

(b) If a dilution zone is authorized within which water quality standards are modified, the dimensions of such dilution zone.