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 10 - Tank Capacity

001 Dwelling

001.01 The minimum septic tank capacity for a single family or multi-family dwelling shall be determined using the design flow (see Chapter 12) and the tank capacity listed in Table 10.1. The capacity of any pump tank or pump chamber is not considered part of or applicable to the required minimum septic tank capacity.

001.02 For a dwelling served by more than one septic system, the total design flow for the dwelling shall be distributed between the separate systems based on the percentage of the design flow that will be conveyed to each system. The minimum septic tank capacity for each system shall be as listed in Table 10.1. In no case shall the minimum septic tank capacity for any system be less than 1,000 gallons.

001.03 A holding tank serving a dwelling shall have a minimum capacity of 1,000 gallons for two or fewer bedrooms plus 300 gallons for each additional bedroom.

001.04 A pump tank serving a dwelling or non-dwelling shall have a minimum storage capacity above the normal high (pump start) operating level for one day of flow at the design flow rate.

002 Non-dwelling facility

002.01 The liquid capacity of a septic tank serving a non-dwelling facility shall be at least equal to 1,125 gallons plus 0.75 times the design flow in gallons per day (gpd) for flows over 1,500 gpd. For flows of 1,500 gpd or less, 1.5 times the design flow may be used but a minimum of a 1,000 gallon tank is required. For a non-dwelling facility served by multiple septic systems, the minimum septic tank capacity for each system shall be 1,000 gallons.

002.02 A holding tank serving a non-dwelling facility shall have a minimum capacity at least five times the daily flow but not less than 1,000 gallons unless approved by the Department in a construction permit and operated in compliance with the subsequent operating permit.

003 For septic systems with design flows greater than 2,000 gpd, the installation of a two-compartment septic tank or two septic tanks installed in series is required.

004 The septic tank capacity required for a septic system receiving high strength or high temperature wastewater, such as from a laundry, butcher shop, camper dump station, restaurant, or similar facility, shall be doubled. Because these types of wastes are not domestic waste, discharge of these wastes to a septic system is prohibited unless construction of the system is approved by the Department in a construction permit and the system is operated in compliance with the subsequent operating permit.

005 Septic tank capacity for a single compartment tank shall be increased by 50 percent to provide adequate attenuation when a pump is used to deliver wastewater from the building, or after the building drain, into the septic tank.

006 The capacity of a septic tank means the interior volume of the tank below the level of the inside bottom of the outlet or effluent pipe. The capacity shall not include the volume of the air space above the normal operating water level of the tank.

007 The capacity of a holding tank or a pump tank means the interior volume of the tank below the level of the inside bottom of the inlet or influent pipe. The capacity shall not include the volume of the air space at the top of the tank.

Table 10.1 - Minimum Septic Tank Capacity for a Dwelling *

Design Flow in Gallons per Day
(see Ch. 12)
Septic Tank Capacity in Gallons
For Dwelling without a Garbage Grinder or a Large Capacity Tub
Dwelling with a
Garbage Grinder
or a Large Capacity Tub
Dwelling with a
Garbage Grinder
and a Large Capacity Tub
200
1,000
1,000
1,000
300
1,000
1,000
1,250
400
1,000
1,250
1,500
500
1,250
1,500
1,750
600
1,500
1,750
2,000
700
1,750
2,000
2,250
800
2,000
2,250
2,500
900
2,250
2,500
2,750
1,000
2,500
2,750
3,000

* A “large capacity tub” means any bathtub or similar fixture with a maximum working volume greater than 50 gallons. A “garbage grinder” is typically used or placed in the kitchen sink drain and may also be referred to as a garbage disposal or waste disposal.


Enabling Legislation: Neb. Rev. Stat. §81-1505(8).

Legal Citation: Title 124, Ch. 10, Nebraska Department of Environmental Quality