Current through Register Vol. 39, No. 6, September 16, 2024
(a) Sewer and sewer
extensions shall not be constructed in the following areas:
(1) a natural area designated on the State
Registry of Natural Heritage Areas by a protection agreement between the owner
and the Secretary, unless no prudent, feasible, or technologically possible
alternative exists; or,
(2) a
natural area dedicated as a North Carolina Nature Preserve by mutual agreement
between the owner and State of North Carolina represented by the Governor and
Council of State, unless the Governor and Council of State agree that no
prudent, feasible, or technologically possible alternative exists;
(b) Engineering design documents.
The following documents shall be prepared prior to submitting a permit
application to the Division. If submittal of such documents is not requested in
the permitting process (i.e., fast-track), they shall be available upon request
by the Division. If required by G.S. 89C, a professional engineer shall prepare
these documents:
[Note: The North Carolina Board of Examiners for Engineers
and Surveyors has determined, via letter dated December 1, 2005, that
preparation of engineering design documents pursuant to this Paragraph
constitutes practicing engineering under G.S. 89C.]
(1) a plan and profile of sewers, showing
their proximity to other utilities and natural features such as water supply
lines, water lines, wells, storm drains, surface waters, wetlands, roads and
other trafficked areas;
(2) design
calculations, including pipe and pump sizing, velocity, pump cycle times and
level control settings, pump station buoyancy, wet well storage, surge
protection, detention time in the wet well and force main, ability to flush low
points in force mains with a pump cycle, and downstream sewer capacity
analysis; and
(3) sewer system
specifications describing all materials to be used, methods of construction,
and means for assuring the quality and integrity of the finished
project.
(c) All deeds,
easements, and encroachment agreements necessary for installation, operation,
and maintenance of the system shall be obtained prior to operation of the
system.
(d) There shall be no
by-pass or overflow lines designed in any new sewer system except for valved
piping and appurtenances intended for emergency pumping operations.
(e) Two feet protection from a 100-year flood
shall be provided unless there is a water-tight seal on all station hatches and
manholes, with control panels and vents extending two feet above the 100-year
flood elevation.
(f) The following
separations shall be provided from the sewer system to the listed feature
except as allowed by Paragraph (g) of this Rule:
|
Storm sewers and other utilities not listed below
(vertical) |
18 inches |
|
Water mains (vertical-water over sewer including in
benched trenches) or (horizontal) |
18 inches
10 feet |
|
Reclaimed water lines (vertical - reclaimed over
sewer) or (horizontal) |
18 inches
2 feet |
|
Any private or public water supply source
consisting of wells, WS-I waters, Class I, Class II, or Class III reservoirs
used as a source of drinking water |
100 feet |
|
Waters classified WS-II, WS-III, WS-IV, B, SA, ORW,
HQW, or SB from normal high water or tide elevation, wetlands that are directly
abutting these waters, and wetlands classified as UWL or SWL
|
50 feet |
|
Any other stream, lake, impoundment, wetlands
classified as WL, waters classified as C, SC, or WS-V, or ground water lowering
and surface drainage ditches |
10 feet |
|
Any building foundation
|
5 feet |
|
Any basement |
10 feet |
|
Top slope of embankment or cuts of 2 feet or more
vertical height
|
10 feet |
|
Drainage systems and interceptor
drains |
5 feet |
|
Any swimming pool |
10 feet |
|
Final earth grade (vertical) |
36 inches |
(g) The following separations shall be
permitted if separations in Paragraph (f) of this Rule cannot be achieved,
provided that nothing in this Paragraph shall supersede the allowable
alternatives provided in the Commission for Public Health Public Water Supply
Rules (15A NCAC 18C), Commission for
Public Health Sanitation Rules (15A NCAC 18A) or the
Groundwater Protection Rules (15A NCAC 02L and
15A NCAC
02C) that pertain to the separation of sewer
systems from water mains or public or private wells:
(1) for storm sewers, engineering solutions
such as ductile iron pipe or structural bridging to prevent crushing the
underlying pipe;
(2) for public or
private wells, piping materials, testing methods, and acceptability standards
meeting water main standards shall be used where these separations cannot be
maintained. All appurtenances shall be outside the 100-foot radius of the well.
The separation shall however not be less than 25 feet from a private well or 50
feet from a public well;
(3) for
public water main horizontal or vertical separations, alternatives as described
in 15A
NCAC 18C .0906;
(4) for less than 36-inches cover from final
earth grade, ductile iron pipe shall be required in any alternative. Ductile
iron pipe or other pipe with proper bedding to develop design supporting
strength shall be provided where sewers are subject to traffic bearing loads;
and
(5) for all other separations,
materials, testing methods, and acceptability standards meeting water main
standards (15A NCAC 18C) shall be required
in any alternative.
(h)
The following criteria shall be met for all pumping stations and force mains:
(1) Pump Station Reliability:
(A) Pump stations shall be designed with
multiple pumps such that peak flow can be pumped with the largest pump out of
service. Simplex pump stations, which are pump stations with only one pump,
shall serve only a single building with an average daily design flow less than
or equal to 600 gallons per day as calculated using Rule .0114 of this
Subchapter.
(B) A standby power
source or pump shall be required at all pump stations except for simplex pump
stations. Controls shall be provided to automatically activate the standby
source and signal an alarm condition.
(C) As an alternative to Part (B) of this
Subparagraph for pump stations with an average daily design flow less than
15,000 gallons per day as calculated using Rule .0114 of this Subchapter, a
portable power source or pumping capability may be used. The portable source
shall be owned or contracted by the permittee and shall be compatible with the
station. If the portable power source or pump is dedicated to multiple pump
stations, an evaluation of all the pump stations' storage capacities and the
rotation schedule of the portable power source or pump in a multiple station
power outage, including travel timeframes, shall be provided.
(D) Simplex pump or vacuum stations
connecting a single building to a sewer system shall provide 24-hours worth of
wastewater storage or shall provide storage in excess of that needed during the
greatest power outage over the last three years or the documented response time
to replace a failed pump, whichever is greater. Documentation of wastewater
storage shall be provided with the permit application. In no case shall less
than 6 hours worth of wastewater storage be provided above the pump-on
level.
(E) All pump stations
designed for two pumps or more shall have a telemetry system to provide remote
notification of a problem condition, including power failure and high water
alarm.
(F) All pump stations shall
have a high water audio and visual alarm.
(2) Pump stations shall have a permanent
weatherproof sign stating the pump station identifier, 24-hour emergency
number, and instructions to call in case of emergency. Simplex pump or vacuum
stations serving a single-family residence shall have a placard or sticker
placed inside the control panel with a 24-hour emergency contact
number.
(3) Wet wells shall be
equipped with screened vents.
(4)
The public shall be restricted from access to the site and equipment.
(5) Air relief valves shall be provided at
all high points along force mains where the vertical distance exceeds ten
feet.
(i) The following
criteria shall be met for gravity sewers:
(1)
public gravity sewers shall be equipped with a minimum eight inch diameter pipe
and private gravity sewers shall be equipped with a minimum six inch diameter
pipe;
(2) the maximum separation
between manholes shall be 425 feet unless documentation is submitted with the
application that the owner has the capability to perform routine cleaning and
maintenance of the sewer at the specified manhole separation; and
(3) drop manholes shall be provided where
invert separations exceed 2.5 feet.
(j) The following criteria shall be met for
low pressure sewers, vacuum sewers, STEP, and other alternative sewers
discharging into another sewer system:
(1)
Hydraulic modeling of the system shall be submitted using the statistically
projected number of pumps running at one time. If computer modeling is provided
by a pump manufacturer, it shall be indicated and shall be considered part of
the design calculations pursuant to Subparagraph (b)(2) of this Rule.
(2) Simplex pump stations shall only serve a
single building with an average daily design flow less than 600 gallons per day
as calculated using Rule .0114 of this Subchapter. All other buildings
connected to the system shall at a minimum have duplex pumps.
(3) Septic tanks shall adhere to the
standards established in
15A NCAC
18A .1900.
Authority
G.S.
143-215.1;
143-215.3(a);
Eff. September 1, 2006;
Readopted Eff. September 1,
2018;
Amended Eff. April 1, 2021.
