NEBRASKA ADMINISTRATIVE CODE
NEBRASKA DEPARTMENT OF ENVIRONMENTAL QUALITY

Title 124 - Rules And Regulations For The Design, Operation And Maintenance of Onsite Wastewater Treatment Systems
Chapter 12 - Design Flow

001 The design flow for components of an onsite wastewater system other than a lagoon shall be as follows:

001.01 For a single-family dwelling, the design flow shall not be less than 100 gallons per day plus 100 gallons per day per bedroom. (See Table 12.1)

001.02 For a multi-family dwelling or multiple single-family dwellings connected to a common onsite wastewater system component, the design flow shall not be less than 100 gallons per day per dwelling unit plus 100 gallons per day per bedroom based on the total number of bedrooms. (See Table 12.2)

001.03 For a non-dwelling facility, the design flow shall not be less than the highest daily wastewater flow that is calculated to be generated based on the characteristics of the occupancy and use of the facility.

002 The design flow for an onsite wastewater lagoon shall be as follows:

002.01 For a single-family or multi-family dwelling, the design flow for a lagoon shall be 150 gallons per day for a one-bedroom dwelling plus 75 gallons per day for each additional bedroom. (See Table 12.3)

002.02 For a non-dwelling facility, the design flow for a lagoon shall be the average daily wastewater flow that is calculated to be generated based on the characteristics of the occupancy and use of the facility. Where the quantity of wastewater generated varies by day, week, month, or season, the design flow may be the average for that period of time provided that the lagoon is designed to have adequate storage volume below the maximum operating level to contain the peak period flows.

003 For non-dwelling facilities, the quantity of flow generated for various occupancy and uses shall be consistent with nationally recognized data published by the United States Environmental Protection Agency, state onsite wastewater regulatory agencies, or nationally recognized plumbing codes. If use of a non-dwelling facility includes residential occupancy, the estimated flow from the non-residential use shall be added to a residential design flow of 100 gallons per day plus 100 gallons per day per bedroom.

Table 12.1 โ€“ Design Flow for Single Family Dwelling

Number of Bedrooms*
1
2
3
4
5
6
7
8
9
Design Flow, Gallons per Day
200
300
400
500
600
700
800
900
1,000
* Design flow for a dwelling with more than 9 bedrooms exceeds 1,000 gallons per day and a construction permit is required.

Table 12.2 โ€“ Design Flow for Multi-Family Dwelling

Number of Dwelling Units
Total Number of Bedrooms
2
3
4
5
6
7
8
Design flow in Gallons per Day
2
400
500
600
700
800
900
1,000
3
500
600
700
800
900
1,000
**
4
600
700
800
900
1,000
**
**
5
700
800
900
1,000
**
**
**
** Design flow exceeds 1,000 gallons per day and a construction permit is required.

Table 12.3 โ€“ Design Flow for a Lagoon for a Single or Multi-Family Dwelling
(Design flow in Gallons per Day)
Total *** Bedrooms
1
2
3
4
5
6
7
8
9
10
11
12
Lagoon Design Flow
150
225
300
375
450
525
600
675
750
825
900
975
*** For lagoon design when the total number of bedrooms exceeds twelve, design flow exceeds 1,000 gallons per day and a construction permit is required.

Enabling Legislation: Neb. Rev. Stat. ยง81-1505(8).

Legal Citation: Title 124, Ch. 12, Nebraska Department of Environmental Quality.