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Chapter 11
North Carolina Water Quality Standards and Classifications
11.1 Description of Surface Water Classifications and Standards
North Carolina’s Water Quality Standards Program adopted classifications and water quality
standards for all the state’s river basins by 1963. The program remains consistent with the
Federal Clean Water Act and its amendments. Water quality classifications and standards have
also been modified to promote protection of surface water supply watersheds, high quality
waters, and the protection of unique and special pristine waters with outstanding resource values.
11.1.1 Statewide Classifications
All surface waters in the state are assigned a primary classification that is appropriate to the best
uses of that water. In addition to primary classifications, surface waters may be assigned a
supplemental classification. Most supplemental classifications have been developed to provide
special protection to sensitive or highly valued resource waters. Table 13 briefly describes the
best uses of each classification. A full description is available in the document titled:
Classifications and Water Quality Standards Applicable to Surface Waters of North Carolina.
Information on this subject is also available at DWQ’s website: http://h2o.enr.state.nc.us/csu/.
11.1.2 Statewide Water Quality Standards
Each primary and supplemental classification is assigned a set of water quality standards that
establish the level of water quality that must be maintained in the waterbody to support the uses
associated with each classification. Some of the standards, particularly for HQW and ORW
waters, outline protective management strategies aimed at controlling point and nonpoint source
pollution. These strategies are discussed briefly below. The standards for C and SC waters
establish the basic protection level for all state surface waters. The other primary and
supplemental classifications have more stringent standards than for C and SC, and therefore,
require higher levels of protection.
Some of North Carolina’s surface waters are relatively unaffected by pollution sources and have
water quality higher than the standards that are applied to the majority of the waters of the state.
In addition, some waters provide habitat for sensitive biota such as trout, juvenile fish, or rare
and endangered aquatic species.
High Quality Waters (Class HQW)
There are no stream miles classified as HQW waters in the Roanoke River basin except for the
WS-II waters that have a supplemental HQW classification (Figure 16). Special HQW
protection management strategies are intended to prevent degradation of water quality below
present levels from both point and nonpoint sources. HQW requirements for new wastewater
discharge facilities and facilities which expand beyond their currently permitted loadings address
oxygen-consuming wastes, total suspended solids, disinfection, emergency requirements,
volume, nutrients (in nutrient sensitive waters) and toxic substances.
Chapter 11 – NC Water Quality Standards and Classifications 111
Table 13 - Primary and Supplemental Surface Water Classifications
PRIMARY FRESHWATER AND SALTWATER CLASSIFICATIONS
Class* Best Uses
C and SC Aquatic life propagation/protection and secondary recreation.
B and SB Primary recreation and Class C and SC uses.
SA Suitable for commercial shellfish harvesting and SB and SC uses.
WS Water Supply (WS): Assigned to watersheds based on land use characteristics. The WS classifications have
management strategies to protect the surface water supply. For WS-I through WS-IV, these include limits on
point source discharges and local programs to control nonpoint source and stormwater runoff. A WS Critical
Area (CA) has more stringent protection measures and is designated within one-half mile from a WS intake
or WS reservoir. All WS classifications are suitable for Class C uses.
WS-I Generally located in natural and undeveloped watersheds.
WS-II Generally located in predominantly undeveloped watersheds.
WS-III Generally located in low to moderately developed watersheds.
WS-IV Generally located in moderately to highly developed watersheds.
WS-V Generally upstream of and draining to Class WS-IV waters. No categorical restrictions on watershed
development or treated wastewater discharges.
SUPPLEMENTAL CLASSIFICATIONS
Class Best Uses
Sw Swamp Waters: Waters that have low velocities and other natural characteristics that are different from
adjacent streams (e.g., lower pH, lower levels of dissolved oxygen).
Tr Trout Waters: Provides protection to freshwaters for natural trout propagation and survival of stocked trout.
HQW High Quality Waters: Waters that have excellent water quality, primary nursery areas and other functional
nursery areas, WS-I and WS-II or SA waters.
ORW Outstanding Resource Waters: Unique and special waters of exceptional state or national recreational or
ecological significance, which require special protection.
NSW Nutrient Sensitive Waters: Waters subject to excessive plant growth and requiring limitations on nutrient
inputs.
• Primary classifications beginning with "S" are assigned to saltwaters.
For nonpoint source pollution, development
activities which require a Sedimentation and
Erosion Control Plan in accordance with rules
established by the NC Sedimentation Control
Commission or an approved local erosion and
sedimentation control program, and which drain to
and are within one mile of HQWs, are required to
control runoff from the development using either a
low density or high density option. The low-density
option requires a 30-foot setback between
development activities and the stream; whereas, the
high-density option requires structural stormwater
controls (e.g., stormwater infiltration system, wet
detention ponds). In addition, the Division of Land
Resources (DLR) requires more stringent erosion
controls for land-disturbing projects within one mile of and draining to HQWs.
Criteria for HQW Classification
• Waters rated as Excellent based on
DWQ’s chemical and biological
sampling.
• Streams designated as native or special
native trout waters by the Wildlife
Resources Commission.
• Waters designated as primary nursery
areas or other functional nursery areas
by the Division of Marine Fisheries.
• Waters classified by DWQ as WS-I,
WS-II or SA.
112 Chapter 11 – NC Water Quality Standards and Classifications
Outstanding Resource Waters (Class ORW)
There are 1.6 stream miles of ORW waters in the
Roanoke River basin (Figure 16). These waters
have excellent water quality (rated based on
biological and chemical sampling as with HQWs)
and an associated outstanding resource.
The requirements for ORW waters are more
stringent than those for HQWs. Special
protection measures that apply to North Carolina
ORWs are set forth in 15A NCAC 2B .0225. At a
minimum, no new discharges or expansions are
permitted, and a 30-foot setback or stormwater
controls for new developments are required. In some circumstances, the unique characteristics
of the waters and resources that are to be protected require that a specialized (or customized)
ORW management strategy be developed.
The ORW rule defines outstanding resource
values as including one or more of the
following:
• an outstanding fisheries resource;
• a high level of water-based recreation;
• a special designation such as National Wild
and Scenic River or a National Wildlife
Refuge;
• within a state or national park or forest; or
• a special ecological or scientific significance.
Primary Recreation (Class B)
There are 111 stream miles, 31,543 freshwater acres and 1,475.5 estuarine acres classified for
primary recreation in the Roanoke River basin. Waters classified as Class B are protected for
primary recreation, include frequent and/or organized swimming, and must meet water quality
standards for fecal coliform bacteria. Sewage and all discharged wastes into Class B waters must
be treated to avoid potential impacts to the existing water quality.
Trout Waters
There are 92.0 stream miles classified as Trout (Tr) waters in the Roanoke River basin (Figure
16). Different water quality standards for some parameters, such as dissolved oxygen,
temperature and turbidity, have been developed to protect freshwaters for natural trout
propagation and survival of stocked trout. These water quality standards result in more
restrictive limits for wastewater discharges to trout water streams. There are no watershed
development restrictions associated with the Tr classification; however, the NC Division of Land
Resources (DLR), under the NC Sedimentation and Pollution Control Act (SPCA), has
requirements for protecting trout streams from land-disturbing activities. The SPCA states that
“waters that have been classified as trout waters by the Environmental Management Commission
(EMC) shall have an undisturbed zone either 25 feet wide or of sufficient width to confine
visible siltation within the twenty-five percent (25 percent) of buffer zone nearest the land-
disturbing activity, whichever is greater” [G.S. 113A-57(1)]. This rule applies to all named and
unnamed tributaries flowing to the affected trout water stream. For more information regarding
land-disturbing activities along designated trout streams, refer to the DLR website at
www.dlr.enr.state.nc.us/.
The NC Wildlife Resources Commission administers a state fishery management classification
known as the Designated Public Mountain Trout Waters. It provides for public access to streams
for fishing and regulates fishing activities (seasons, size limits, creel limits, and bait and lure
restrictions). Although many of these waters are also classified Tr by DWQ, this is not the same
classification.
Chapter 11 – NC Water Quality Standards and Classifications 113
Swamp Waters
There are 237.3 stream miles and 1,475.5 estuarine acres classified as Swamp (Sw) waters in the
Roanoke River basin. These waters are recognized as waters that will naturally be more acidic
(have lower pH values) and have lower levels of dissolved oxygen.
Water Supply Watersheds (Class WS)
There are 246 stream miles and 26,320 freshwater acres currently classified for water supply in
the Roanoke River basin (Figure 16). The purpose of the Water Supply Watershed Protection
Program is to provide a proactive drinking water supply protection program for communities.
Local governments administer the program based on state minimum requirements. There are
restrictions on wastewater discharges, development, landfills and residual application sites to
control the impacts of point and nonpoint sources of pollution to water supplies.
There are five water supply classifications (WS-I to WS-V) that are defined according to the land
use characteristics of the watershed. The WS-I classification carries the greatest protection for
water supplies. No development is allowed in these watersheds. Generally, WS-I lands are
publicly owned. WS-V watersheds have the least amount of protection and do not require
development restrictions. These are either former water supply sources or sources used by
industry. WS-I and WS-II classifications are also HQW by definition because requirements for
these levels of water supply protection are at least as stringent as those for HQWs. Those
watersheds classified as WS-II through WS-IV require local governments having jurisdiction
within the watersheds to adopt and implement land use ordinances for development that are at
least as stringent as the state’s minimum requirements. A minimum 30-foot setback is required
on perennial streams in those watersheds in low-density areas; a minimum 100 feet setback is
required in high-density areas. The Roanoke River basin currently contains, WS-II, WS-III, WS-
IV and WS-V water supply watersheds. Water supply watersheds in the Roanoke River basin
cover 26,320 Acres and 246 stream miles.
11.2 Reclassification of Surface Waters
The classification of a surface water may be changed if a request is submitted by a local
government, watershed group, or a local citizen. DWQ reviews each request for reclassification
and conducts an assessment of the surface water to determine if the reclassification is
appropriate. If it is determined that a reclassification is justified, the request must proceed
through the state rule-making process. To initiate a reclassification, the “Application to Request
Reclassification of NC Surface Waters” must be completed and submitted to DWQ’s
Classification and Standards Unit. For more information on requests for reclassification and
contact information, visit http://h2o.enr.state.nc.us/csu/.
11.2.1 Pending and Recent Reclassifications in the Roanoke River Basin
In Chapters 1 through 10, DWQ identified those surface waters as having Excellent
bioclassification, and therefore, may be eligible for reclassification. There may also be many
other surface waters eligible for reclassification that were not identified with the subbasin
chapters. Both private and public stakeholders play an important role in the reclassification
process and are responsible for filing formal requests with DWQ for reclass consideration.
114 Chapter 11 – NC Water Quality Standards and Classifications
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Figure 16 ORW* , Water Supply Watershed, and Trout Waters
in the Roanoke River Basin**
Planning Section
Basinwide Planning Unit
May 30, 2006
*The only ORW for this basin is in Stokes County, southwest of Danbury.
**All ORW's, WSW's and Trout Waters are located between subbasins 03-02-01 and 03-02-08.
0 102030405
Miles
Legend
Trout Waters
WS-II
WS-IV
ORW
WS-III
Hydrography
Subbasin Boundary
Counties
116 Chapter 11 – NC Water Quality Standards and Classifications