15a ncac 02b .0216 FRESH SURFACE WATER QUALITY STANDARDS FOR CLASS WS-IV WATERS

The following water quality standards shall apply to surface waters within water supply watersheds classified as WS-IV. Water quality standards applicable to Class C waters as described in Rule .0211 of this Section shall also apply to Class WS-IV waters.

(1) The best usage of waters classified as WS-IV shall be as a source of water supply for drinking, culinary, or food-processing purposes for those users where a more protective WS-I, WS-II or WS-III classification is not feasible as determined by the Commission in accordance with Rules .0212 through .0215 of this Section and any other best usage specified for Class C waters.

(2) The best usage of waters classified as WS-IV shall be maintained as follows:

(a) Water quality standards in a WS-IV watershed shall meet the requirements as specified in Item (3) of this Rule.

(b) Wastewater and stormwater point source discharges in a WS-IV watershed shall meet the requirements as specified in Item (4) of this Rule.

(d) Following approved treatment, as defined in Rule .0202 of this Section, the waters shall meet the Maximum Contaminant Level concentrations considered safe for drinking, culinary, or food‑processing purposes that are specified in 40 CFR Part 141 National Primary Drinking Water Regulations and in the North Carolina Rules Governing Public Water Supplies, 15A NCAC 18C .1500.

(e) Sources of water pollution that preclude any of the best uses on either a short‑term or long‑term basis shall be deemed to violate a water quality standard.

(f) The Class WS-II or WS-III classifications may be used to protect portions of Class WS-IV water supplies. For reclassifications of these portions of WS-IV water supplies occurring after the July 1, 1992 statewide reclassification, a WS-IV classification that is requested by local governments shall be considered by the Commission if all local governments having jurisdiction in the affected areas have adopted a resolution and the appropriate ordinances as required by G.S. 143-214.5(d) to protect the watershed or if the Commission acts to protect a watershed when one or more local governments has failed to adopt protective measures as required by this Sub-Item.

(3) Water quality standards applicable to Class WS-IV Waters shall be as follows:

(a) MBAS (Methylene-Blue Active Substances): not greater than 0.5 mg/l to protect the aesthetic qualities of water supplies and to prevent foaming;

(b) Odor producing substances contained in sewage, industrial wastes, or other wastes: only such amounts, whether alone or in combination with other substances or waste, as will not cause organoleptic effects in water supplies that cannot be corrected by treatment, impair the palatability of fish, or have an adverse impact, as defined in 15A NCAC 02H .1002, on any best usage established for waters of this class;

(c) Chlorinated phenolic compounds: not greater than 1.0 ug/l to protect water supplies from taste and odor problems due to chlorinated phenols shall be allowed. Specific phenolic compounds may be given a different limit if it is demonstrated not to cause taste and odor problems and not to be detrimental to other best usage;

(d) Total hardness: not greater than 100 mg/l as calcium carbonate (CaCO₃or Ca + Mg);

(e) Solids, total dissolved: not greater than 500 mg/l;

(f) Toxic and other deleterious substances that are non-carcinogens:

(i) Barium: 1.0 mg/l;

(ii) Chloride: 250 mg/l;

(iii) Nickel: 25 ug/l;

(iv) Nitrate nitrogen: 10.0 mg/l;

(v) 2,4‑D: 70 ug/l;

(vi) 2,4,5‑TP (Silvex): 10 ug/l; and

(vii) Sulfates: 250 mg/l;

(g) Toxic and other deleterious substances that are carcinogens:

(i) Aldrin: 0.05 ng/1;

(ii) Arsenic: 10 ug/l;

(iii) Benzene: 1.19 ug/1;

(iv) Carbon tetrachloride: 0.254 ug/l;

(v) Chlordane: 0.8 ng/1;

(vi) Chlorinated benzenes: 488 ug/l;

(vii) DDT: 0.2 ng/1;

(viii) Dieldrin: 0.05 ng/1;

(ix) Dioxin: 0.000005 ng/l;

(x) Heptachlor: 0.08 ng/1;

(xi) Hexachlorobutadiene: 0.44 ug/l;

(xii) Polynuclear aromatic hydrocarbons (total of all PAHs): 2.8 ng/l;

(xiii) Tetrachloroethane (1,1,2,2): 0.17 ug/l;

(xiv) Tetrachloroethylene: 0.7 ug/l;

(xv) Trichloroethylene: 2.5 ug/l; and

(xvi) Vinyl Chloride: 0.025 ug/l.

(4) Wastewater and stormwater point source discharges in a WS-IV watershed shall meet the following requirements:

(a) Discharges that qualify for a General NPDES Permit pursuant to 15A NCAC 02H .0127 shall be allowed in the entire watershed.

(b) Discharges from domestic facilities, industrial facilities and trout farms that are subject to Individual NPDES Permits shall be allowed in the entire watershed.

(c) Stormwater discharges that qualify for an Individual NPDES Permit pursuant to 15A NCAC 02H .0126 shall be allowed in the entire watershed.

(d) No discharge of sewage, industrial wastes, or other wastes shall be allowed in the entire watershed except for those allowed by Sub-Items (a) through (c) of this Item or Rule .0104 of this Subchapter, and none shall be allowed that have an adverse effect on human health or that are not treated in accordance with the permit or other requirements established by the Division pursuant to G.S. 143-215.1. Upon request by the Commission, dischargers or industrial users subject to pretreatment standards shall disclose all chemical constituents present or potentially present in their wastes and chemicals that could be spilled or be present in runoff from their facility which may have an adverse impact on downstream water supplies. These facilities may be required to have spill and treatment failure control plans as well as perform special monitoring for toxic substances.

(e) New industrial discharges of treated wastewater in the critical area shall meet the provisions of Rule .0224(c)(2)(D), (E), and (G) of this Section and Rule .0203 of this Section.

(f) New industrial connections and expansions to existing municipal discharges with a pretreatment program pursuant to 15A NCAC 02H .0904 shall be allowed in the entire watershed.

(g) No new landfills shall be allowed in the Critical Area.

(h) No new permitted sites for land application residuals or petroleum contaminated soils shall be allowed in the Critical Area.

(5) Nonpoint source pollution in a WS-IV watershed shall meet the following requirements:

(a) Nonpoint source pollution shall not have an adverse impact on waters for use as a water supply or any other designated use.

(b) Class WS-IV waters shall be protected as water supplies that are located in watersheds that meet average watershed development density levels specified for Class WS-IV waters in Rule .0624 of this Subchapter.

History Note: Authority G.S. 143‑214.1; 143‑215.3(a)(1);

Eff. February 1, 1986;

Amended Eff. January 1, 2015; May 1, 2007; April 1, 2003; June 1, 1996; October 1, 1995; August 1, 1995; June 1, 1994;

Readopted Eff. November 1, 2019.