North Carolina Administrative Code
Title 15A - Environmental Quality
Chapter 02 - ENVIRONMENTAL MANAGEMENT
Subchapter T - WASTE NOT DISCHARGED TO SURFACE WATERS
Section .0100 - GENERAL REQUIREMENTS
Section 02T .0114 - WASTEWATER DESIGN FLOW RATES

Universal Citation: 15A NC Admin Code 02T .0114

Current through Register Vol. 39, No. 6, September 16, 2024

(a) This Rule shall be used to determine wastewater flow rates for all systems governed by this Subchapter unless alternate criteria are provided by a program-specific rule or for flow used for the purposes of 15A NCAC 02H .0105. Higher flow rates shall be required where usage and occupancy are atypical, including those in Paragraph (e) of this Rule. Wastewater flow calculations shall take hours of operation and anticipated maximum occupancies and usage into account when calculating peak flows for design.

(b) In determining the volume of sewage from dwelling units, the flow rate shall be 120 gallons per day per bedroom. The minimum volume of sewage from each dwelling unit shall be 240 gallons per day and each additional bedroom above two bedrooms shall increase the volume by 120 gallons per day. Each bedroom or any other room or addition that can function as a bedroom shall be considered a bedroom for design purposes. When the occupancy of a dwelling unit exceeds two persons per bedroom, the volume of sewage shall be determined by the maximum occupancy at a rate of 60 gallons per person per day.

(c) The following table shall be used to determine the minimum allowable design daily flow of wastewater facilities. Design flow rates for establishments not identified below shall be determined using available flow data, water-using fixtures, occupancy or operation patterns, and other measured data.

Type of Establishments

Daily Flow For Design

Barber and beauty shops

Barber Shops

50 gal/chair

Beauty Shops

125 gal/booth or bowl

Businesses, offices and factories

General business and office facilities

25 gal/employee/shift

Factories, excluding industrial waste

25 gal/employee/shift

Factories or businesses with showers or food preparation

35 gal/employee/shift

Warehouse

100 gal/loading bay

Warehouse . self storage (not including caretaker residence)

1 gal/unit

Churches

Churches without kitchens, day care or camps

3 gal/seat

Churches with kitchen

5 gal/seat

Churches providing day care or camps

25 gal/person (child & employee)

Fire, rescue and emergency response facilities

Fire or rescue stations without on site staff

25 gal/person

Fire or rescue stations with on-site staff

50 gal/person/shift

Food and drink facilities

Banquet, dining hall

30 gal/seat

Bars, cocktail lounges

20 gal/seat

Caterers

50 gal/100 sq ft floor space

Restaurant, full Service

40 gal/seat

Restaurant, single service articles

20 gal/seat

Restaurant, drive-in

50 gal/car space

Restaurant, carry out only

50 gal/100 sq ft floor space

Institutions, dining halls

5 gal/meal

Deli

40 gal/100 sq ft floor space

Bakery

10 gal/100 sq ft floor space

Meat department, butcher shop or fish market

75 gal/100 sq ft floor space

Specialty food stand or kiosk

50 gal/100 sq ft floor space

Hotels and Motels

Hotels, motels and bed &breakfast facilities,

without in-room cooking facilities

120 gal/room

Hotels and motels, with in-room cooking facilities

175 gal/room

Resort hotels

200 gal/room

Cottages, cabins

200 gal/unit

Self service laundry facilities

500 gal/machine

Medical, dental, veterinary facilities

Medical or dental offices

250 gal/practitioner/shift

Veterinary offices (not including boarding)

250 gal/practitioner/shift

Veterinary hospitals, kennels, animal boarding facilities

20 gal/pen, cage, kennel or stall

Hospitals, medical

300 gal/bed

Hospitals, mental

150 gal/bed

Convalescent, nursing, rest homes without laundry facilities

60 gal/bed

Convalescent, nursing, rest homes with laundry facilities

120 gal/bed

Residential care facilities

60 gal/person

Parks, recreation, camp grounds, R-V parks and other outdoor activi

y facilities

Campgrounds with comfort station, without water or sewer hookups

75 gal/campsite

Campgrounds with water and sewer hookups

100 gal/campsite

Campground dump station facility

50 gal/space

Construction, hunting or work camps with flush toilets

60 gal/person

Construction, hunting or work camps with chemical or portable toilets

40 gal/person

Parks with restroom facilities

250 gal/plumbing fixture

Summer camps without food preparation or laundry facilities

30 gal/person

Summer camps with food preparation and laundry facilities

60 gal/person

Swimming pools, bathhouses and spas

10 gal/person

Public access restrooms

325 gal/plumbing fixture

Schools, preschools and day care

Day care and preschool facilities

25 gal/person (child & employee)

Schools with cafeteria, gym and showers

15 gal/student

Schools with cafeteria

12 gal/student

Schools without cafeteria, gym or showers

10 gal/student

Boarding schools

60 gal/person (student & employee)

Service stations, car wash facilities

Service stations, gas stations

250 gal/plumbing fixture

Car wash facilities

1200 gal/bay

Sports centers

Bowling center

50 gal/lane

Fitness, exercise, karate or dance center

50 gal/100 sq ft

Tennis, racquet ball

50 gal/court

Gymnasium

50 gal/100 sq ft

Golf course with only minimal food service

250 gal/plumbing fixture

Country clubs

60 gal/member or patron

Mini golf, putt-putt

250 gal/plumbing fixture

Go-kart, motocross

250 gal/plumbing fixture

Batting cages, driving ranges

250 gal/plumbing fixture

Marinas without bathhouse

10 gal/slip

Marinas with bathhouse

30 gal/slip

Video game arcades, pool halls

250 gal/plumbing fixture

Stadiums, auditoriums, theaters, community centers

5 gal/seat

Stores, shopping centers, malls and flea markets

Auto, boat, recreational vehicle dealerships/showrooms with restrooms

125 gal/plumbing fixture

Convenience stores, with food preparation

60 gal/100 sq ft

Convenience stores, without food preparation

250 gal/plumbing fixture

Flea markets

30 gal/stall

Shopping centers and malls with food service

130 gal/1000 sq ft

Stores and shopping centers without food service

100 gal/1000 sq ft

Transportation terminals . air, bus, train, ferry, port and dock

5 gal/passenger

(d) Design daily flow rates for proposed non-residential developments where the types of use and occupancy are not known shall be designed for a minimum of 880 gallons per acre, or the applicant shall specify an anticipated flow based upon anticipated or potential uses.

(e) Design daily flow rates for residential property on barrier islands and similar communities located south or east of the Atlantic Intracoastal Waterway and used as vacation rental as defined in G.S. 42A-4 shall be 120 gallons per day per habitable room. Habitable room shall mean a room or enclosed floor space used or intended to be used for living or sleeping, excluding kitchens and dining areas, bathrooms, shower rooms, water closet compartments, laundries, pantries, foyers, connecting corridors, closets, and storage spaces.

(f) An adjusted daily sewage flow design rate shall be granted for permitted but not yet tributary connections and future connections tributary to the system upon showing that the capacity of a sewage system is adequate to meet actual daily wastewater flows from a facility included in Paragraph (b) or (c) of this Rule without causing flow violations at the receiving wastewater treatment plant or capacity-related sanitary sewer overflows within the collection system as follows:

(1) Documented, representative data from that facility or a comparable facility shall be submitted by an authorized signing official in accordance with Rule .0106 of this Section to the Division for all flow reduction requests, as follows:
(A) dates of flow meter calibrations during the time frame evaluated and indication if any adjustments were necessary;

(B) a breakdown of the type of connections (e.g. two bedroom units, three bedroom units) and number of customers for each month of submitted data as applicable. Identification of any non-residential connections including subdivision clubhouses and pools, restaurants, schools, churches and businesses. For each non-residential connection, information identified in Paragraph (c) of this Rule (e.g. 200 seat church, 40 seat restaurant, 35 person pool bathhouse);

(C) a letter of agreement from the owner or an official, meeting the criteria of Rule .0106 of this Section, of the receiving collection system or treatment works accepting the wastewater and agreeing with the adjusted design rate;

(D) age of the collection system;

(E) analysis of inflow and infiltration within the collection system or receiving treatment plant, as applicable;

(F) if a dedicated wastewater treatment plant serves the specific area and is representative of the residential wastewater usage, at least the 12 most recent consecutive monthly average wastewater flow readings and the daily total wastewater flow readings for the highest average wastewater flow month per customers, as reported to the Division;

(G) if daily data from a wastewater treatment plant cannot be used or is not representative of the project area: 12 months worth of monthly average wastewater flows from the receiving treatment plant shall be evaluated to determine the peak sewage month. Daily wastewater flows shall then be taken from a flow meter installed at the most downstream point of the collection area for the peak month selected that is representative of the project area. Justification for the selected placement of the flow meter shall also be provided; and

(H) an estimated design daily sewage flow rate shall be determined by calculating the numerical average of the top three daily readings for the highest average flow month. The calculations shall also account for seasonal variations, excessive inflow and infiltration, age and suspected meter reading and recording errors.

(2) The Division shall evaluate all data submitted but shall also consider other factors in granting, with or without adjustment, or denying a flow reduction request including: applicable weather conditions during the data period (i.e. rainy or drought), other historical monitoring data for the particular facility or other similar facilities available to the Division, the general accuracy of monitoring reports and flow meter readings, and facility usage, such as whether the facility is in a resort area.

(3) Flow increases shall be required if the calculations required by Subparagraph (f)(1) of this Rule yield design flows higher than that specified in Paragraphs (b) or (c) of this Rule.

(4) The permittee shall retain the letter of any approved adjusted daily design flow rate for the life of the facility and shall transfer such letter to a future permittee.

Authority G.S. 143-215.1; 143-215.3(a)(1);
Eff. September 1, 2006;
Readopted Eff. September 1, 2018.

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