North Carolina Administrative Code › Title 15A - Environmental Quality › Chapter 18 - ENVIRONMENTAL HEALTH › Subchapter A - SANITATION › Section .1900 - SEWAGE TREATMENT AND DISPOSAL SYSTEMS › Section 18A .1949 - SEWAGE FLOW RATES FOR DESIGN UNITS

Current through Register Vol. 39, No. 2, July 15, 2024
(a) 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 of sewage by 120 gallons per day. In
				  determining the number of bedrooms in a dwelling unit, each bedroom and any
				  other room or addition that can reasonably be expected to 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.
(b) Table No. I shall be used
				  to determine the minimum design daily flow of sewage required in calculating
				  the design volume of sanitary sewage systems to serve selected types of
				  establishments. The minimum design volume of sewage from any establishment
				  shall be 100 gallons per day. Design of sewage treatment and disposal systems
				  for establishments not identified in this Rule shall be determined using
				  available flow data, water-using fixtures, occupancy or operation patterns, and
				  other measured data.
TABLE NO. I
TYPE OF ESTABLISHMENT
DAILY FLOW FOR DESIGN
Airports
5 gal/passenger
(Also R.R. stations, bus terminals --not including
								food service facilities)
Barber Shops
50 gal/chair
Bars, Cocktail Lounges (Not including food
								service)
20 gal/seat
Beauty Shops (Style Shops)
125 gal/chair
Bowling Lanes
50 gal/lane
Businesses (other than those listed elsewhere in
								this table)
25 gal/employee
Camps
Construction or Work Camps
60 gal/person
40 gal/person (with chemical toilets)
Summer Camps
60 gal/person
Campgrounds -- With Comfort Station
(Without water and sewer hookups)
100 gal/campsite
Travel Trailer/Recreational Vehicle Park (With
								water and sewer hookups)
120 gal/space
Churches (Not including a Kitchen, Food Service
								Facility, Day Care or Camp)
3 gal/seat
Churches (With a Kitchen but, not including a Food
								Service Facility, Day Care, or Camp)
5 gal/seat
Country Clubs
20 gal/member
Day Care Facilities
15 gal/person
Factories (Exclusive of industrial
								waste)
25 gal/person/shift
Add for showers
10 gal/person/shift
Food Service Facilities Restaurants
40 gal/seat or 40 gal/15 ft2 of dining area,
								whichever is greater
24-hour Restaurant
75 gal/seat
Food Stands
(1) Per 100 square feet of food stand floor
								space
50 gal
(2) Add per food employee
25 gal
Other Food Service Facilities
5 gal/meal
Hospitals
300 gal/bed
Marinas
10 gal/boat slip
With bathhouse
30 gal/boat slip
Meat Markets
(1) Per 100 square feet of market floor
								space
50 gal
(2) Add per market employee
25 gal
Motels/Hotels
120 gal/room
With cooking facilities
175 gal/room
Offices (per shift)
25 gal/person
Residential Care Facilities
60 gal/person
Rest Homes and Nursing Homes
With laundry
120 gal/bed
Without laundry
60 gal/bed
Schools
Day Schools
With cafeteria, gym, and showers
15 gal/student
With cafeteria only
12 gal/student
With neither cafeteria nor showers
10 gal/student
Boarding Schools
60 gal/person
Service Stations
250 gal/water closet or urinal
24-hour Service Stations
325 gal/water closet
Stores, Shopping Centers, and Malls (Exclusive of
								food service and meat markets)
120 gal/1000 ft2 of retail sales area
Stadium, Auditorium, Theater,
								Drive-in
5 gal/seat or space
Swimming Pools, Spas, and
								Bathhouses
10 gal/person
(c) An adjusted design daily sewage flow may
				  be granted by the local health department upon a showing as specified in
				  Subparagraphs (c)(1) through (c)(2) that a sewage system is adequate to meet
				  actual daily water consumption from a facility included in Paragraph (b) of
				  this Rule.
(1) Documented data from that
				  facility or a comparable facility justifying a flow rate reduction shall be
				  submitted to the local health department and the State. The submitted data
				  shall consist of at least 12 previous consecutive monthly total water
				  consumption readings and at least 30 consecutive daily water consumption
				  readings. The daily readings shall be taken during a projected normal or above
				  normal sewage flow month. A peaking factor shall be derived by dividing the
				  highest monthly flow as indicated from the 12 monthly readings by the sum of
				  the 30 consecutive daily water consumption readings. The adjusted design daily
				  sewage flow shall be determined by taking the numerical average of the greatest
				  ten percent of the daily readings and multiplying by the peaking factor.
				  Further adjustments shall be made in design sewage flow rate used for sizing
				  nitrification fields and pretreatment systems when the sampled or projected
				  wastewater characteristics exceed those of domestic sewage, such as wastewater
				  from restaurants or meat markets.
(2) An adjusted daily sewage flow rate may be
				  granted contingent upon use of extreme water-conserving fixtures, such as
				  toilets which use 1.6 gallons per flush or less, spring-loaded faucets with
				  flow rates of one gallon per minute or less, and showerheads with flow rates of
				  two gallons per minute or less. The amount of sewage flow rate reduction shall
				  be determined by the local health department and the State based upon the type
				  of fixtures and documentation of the amount of flow reduction to be expected
				  from the proposed facility. Adjusted daily flow rates based upon use of
				  water-conserving fixtures shall apply only to design capacity requirements of
				  dosing and distribution systems and nitrification fields. Minimum pretreatment
				  capacities shall be determined by the design flow rate of Table I of this
				  Rule.