Current through Register Vol. 39, No. 6, September 16, 2024
The following water quality standards shall apply to
surface waters within water supply watersheds classified as WS-I. Water quality
standards applicable to Class C waters as described in Rule .0211 of this
Section shall also apply to Class WS-I waters.
(1) The best usage of waters classified as
WS-I shall be as a source of water supply for drinking, culinary, or food
processing purposes for those users desiring maximum protection of their water
supplies in the form of the most stringent WS classification, and any best
usage specified for Class C waters. Class WS-I waters are waters located on
land in public ownership and waters located in undeveloped
watersheds.
(2) The best usage of
waters classified as WS-I shall be maintained as follows:
(a) Water quality standards in a WS-I
watershed shall meet the requirements as specified in Item (3) of this
Rule.
(b) Wastewater and stormwater
point source discharges in a WS-I watershed shall meet the requirements as
specified in Item (4) of this Rule.
(c) Nonpoint source pollution in a WS-I
watershed shall meet the requirements as specified in Item (5) 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, and 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, incorporated by reference
including subsequent amendments and editions.
(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-I classification may be used
to protect portions of Class WS-II, WS-III, and WS-IV water supplies. For
reclassifications occurring after the July 1, 1992 statewide reclassification,
a WS-I 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-I 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) Total
coliforms shall not exceed 50/100 ml (MF count) as a monthly geometric mean
value in watersheds serving as unfiltered water supplies;
(c) Chlorinated phenolic compounds: not
greater than 1.0 ug/l to protect water supplies from taste and odor problems
from chlorinated phenols;
(d)
Solids, total dissolved: not greater than exceed 500 mg/l;
(e) Total hardness: not greater than 100 mg/l
as calcium carbonate (CaCO3 or Ca + Mg);
(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-I watershed shall be permitted pursuant to
15A NCAC
02B .0104.
(5) Nonpoint source pollution in a WS-I
watershed shall not have an adverse impact, as defined in
15A NCAC
02H .1002, on use as a water supply or any
other designated use.
Authority
G.S.
143-214.1;
143-215.3(a)(1);
Eff. February 1, 1976;
Amended Eff. January 1, 2015; May 1, 2007;
April 1, 2003; October 1, 1995; February 1, 1993; March 1, 1991; October 1,
1989;
Readopted Eff. November 1,
2019.
