Omaha Municipal Code § 49-900 Generally.
Sec. 49-900. - Generally.
Fixture units are determined by the frequencies of use, the periods of maximum use, the average rates of use and the time of use.
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(Ord. No. 40524, § 1, 10-20-15)
GENERALLY
Omaha Municipal Code ch. 49, art. IX, div. 1
in effectOmaha Municipal Code § 49-901 Assigned fixture unit values.
Sec. 49-901. - Assigned fixture unit values.
Fixture unit values listed in Table 49-901 list the relative anticipated volume rating for each type of fixture. These values shall be employed to calculate the estimated volume carried by soil and waste pipe.
Fixtures not listed in Table 49-901 shall be rated on the basis of discharge to the soil or waste system. (See Table 49-907(d).)
Table 49-901
Fixture | Trap Size (inches) | Branch (inches) | Fixture Unit
Bar sink:
Residential | See Note 8 | 1¼ | 1¼ | 1
Commercial w/ four compartments | 1½ | 1½ | 2
Bathtub | 1½ | 1½ | 2
Beer taps | See Note 1 | 1¼ | 1¼ | 1
Bidets | 1½ | 1½ | 2
Cuspidors | 1¼ | 1¼ | 1
Dental units | 1¼ | 1¼ | 1
Disposal:
Residential | 1½ | 1½ | 2
Commercial w/ two-inch trap | See Note 7 | 2 | 2 | 2
Commercial w/ three-inch trap | See Note 7 | 3 | 3 | 3
Drinking fountain | 1¼ | 1¼ | 1
Dishwasher:
Residential | See Note 2 | 1½ | 1½ | 2
Commercial
Single rack | See Note 2 | 2 | 2 | 2
Conveyor type | 3 | 3 | 3
Floor drain | See Note 10 | See Note 10 | See Note 10 | See Note 10
Floor sink | See Note 10
Flushing rim sink | 3 | 3 | 6
Glass washer | 1½ | 1½ | 2
Laundry sink | 1½ | 1½ | 2
Lavatory (basin) | 1¼ | 1¼ | 1
Mop sink (floor outlet):
two-inch | 2 | 2 | 2
three-inch | 3 | 3 | 3
Pedicure foot bath | 1½ | 1½ | 2
Service sink:
With a two-inch trap standard | 2 | 2 | 2
With a three-inch trap standard | 3 | 3 | 3
Shower stall | See Note 6 | 2 | 2 | 2
Sink-residential (Kitchen) W/dishwasher/ disposal | 1½ | 1½ | 2
Sink—commercial two- or three-compartment | 2 | 2 | 3
Sink—commercial pot | 1½ | 1½ | 2
Sitz bath | 1½ | 1½ | 2
Shampoo sink | 1½ | 1½ | 2
Urinals:
Floor urinal | 2 | 2 | 2
Pedestal urinals | 3 | 3 | 6
Wall urinal (exposed trap) | See Note 3 | 1½ | 1½ | 2
Wall urinal (integral trap) | 2 | 2 | 2
Trough urinal | See Note 4
Water closet
Residential | 3 | 3 | 3
Commercial | 3 | 3 | 4
Places of assembly and establishments serving liquor | 3 | 3 | 6
Wash fountains circular | 2 | 2 | 2
Wash fountains— ¼ and ½ circular with multiple water sprays | See Note 9 | 1½ | 1½ | 2
Washers, clothes:
Residential | See Note 5 | 2 | 2 | 3
Commercial (pump) | See Note 5 | 2 | 2 | 3
Commercial (gravity) | 4 | 4 | 6
Additional criteria are as follows:
Note 1: Beer taps should be run indirect when possible (see section 49-1013).
Note 2: See section 49-606.
Note 3: Repair and replacement of existing fixture only.
Note 4: Plumbing board approval required.
Note 5: Clothes washers in groups of three or more shall be rated at six units each for the purpose of common waste pipe sizing.
Note 6: Refer to section 49-622 for further specifications.
Note 7: Disposals shall not be installed in a commercial kitchen (see section 49-613).
Note 8: A bar sink with a 3½ inch diameter strainer will be rated as two fixture units and shall have a minimum 1½-inch waste opening.
Note 9: Wash fountains, either one-quarter or one-half circular with multiple water sprays shall have a rating equal to 0.5 fixture unit for each water spray, but no less than one fixture unit.
Note 10: Floor drains and floor sinks shall have a fixture rating base on the size of the drain outlet. When the floor drain or floor sink is used to receives the discharge from an indirect waste, the rating shall be based on the discharge of the discharging fixture.
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(Ord. No. 40524, § 1, 10-20-15)
Omaha Municipal Code § 49-902 Branch soil and waste lines.
Sec. 49-902. - Branch soil and waste lines.
A branch soil and waste line may be extended to the first floor to receive the discharge of no more than one water closet and one lavatory (basin), subject to the following provisions (see Figure 902):
(a) The vertical riser shall not exceed 15 feet.
(b) The stack vent may be reduced to 1½-inches with approved reducing fittings. Heal inlet one-quarter bends shall be installed vertically.
(c) When a stack is extended to receive fixtures from floors above the first floor or extended to the first floor to receive more than one closet, the stack shall be run full size. (See Figure 49-902(c).)
(d) A separate waste may be connected to a horizontal or vertical branch below the water closet and extended horizontally and vertically for waste on the first floor and above. Fixture units are not to exceed the branch chart in sections 49-903 and 49-906. (See Figure 49-902(d).)
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(Ord. No. 40524, § 1, 10-20-15)
Omaha Municipal Code § 49-903 Capacities of horizontal building drains and building sewers.
Sec. 49-903. - Capacities of horizontal building drains and building sewers.
To determine the capacity of horizontal building drains and building sewers, use Table 49-903:
Table 49-903
Diameter of pipe. (inches) | Permissible number of fixture units
1/16 Inch per Foot | ⅛ Inch per Foot | ¼ Inch per Foot | ½ Inch per Foot | Maximum Length | Maximum Number of WC
1¼ | 1 | 1 | 45 | 0
1½ | 3 | 3 | 60 | 0
2 Note 1 | 16 | 16 | 75 | 0
3 Note 2 | 36 | 48 | 70 | 150 | 3
4 Note 3 | 180 | 216 | 250 | Unlimited
5 | 360 | 400 | 480 | 560 | Unlimited
6 | 600 | 660 | 790 | 940 | Unlimited
8 | 1,400 | 1,600 | 1,920 | 2,240 | Unlimited
10 | 2,400 | 2,700 | 3,240 | 3,780 | Unlimited
12 | 3,600 | 4,200 | 5,000 | 6,000 | Unlimited
15 | 7,000 | 8,300 | 10,000 | 12,000 | Unlimited
Note 1: Maximum of three two-inch floor drains or floor sinks.
Note 2:
(a) Maximum of three clothes washers.
(b) Four W. C. may be installed in single-family dwellings provided that the W.C. uses 1.6 gallon or less per flush.
Note 3:
(a) A maximum of 30 back-to-back clothes washers may be installed on a four-inch waste. Increase to six-inch thereafter.
(b) A maximum of 22 in-line clothes washers on a four-inch waste. Increase to six-inch thereafter.
(c) A maximum of four discharge hoses from clothes washers shall be permitted for each four-inch trap with a standpipe.
Note 4: All soil and waste piping larger than two inches (and all sewers) shall be laid with a minimum slope of one-eighth inch per foot or one percent. Soil, waste and sewer piping with less than the required slope may be installed if, after review of plans designed by a registered mechanical/plumbing engineer licensed to practice in the State of Nebraska, approved by the chief plumbing inspector. However, there shall not be less than 0.5 percent slope on any pipe.
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(Ord. No. 40524, § 1, 10-20-15)
Omaha Municipal Code § 49-904 Cooling tower drains.
Sec. 49-904. - Cooling tower drains.
All cooling tower drains and overflows shall discharge into a special waste sump that is at least 12 inches × 12 inches × 12 inches with a floor drain in the bottom connected to a sanitary sewer. Cooling towers (or other special devices) wasting water shall not be allowed to discharge onto any other private or public property creating a continuous nuisance or dangerous condition.
(Ord. No. 40524, § 1, 10-20-15)
Omaha Municipal Code § 49-905 Soil, waste and vent stacks generally.
Sec. 49-905. - Soil, waste and vent stacks generally.
Buildings shall have soil, waste, or vent stacks extending through the roof. Stacks must be run as direct as possible. The required size of soil or waste stacks shall be determined by the distribution and total of all fixtures connected to the stack in accordance with sections 49-901 and 49-906.
(Ord. No. 40524, § 1, 10-20-15)
Omaha Municipal Code § 49-906 Soil and waste stack sizes.
Sec. 49-906. - Soil and waste stack sizes.
Soil and waste stacks shall be sized according to Table 49-906:
Table 49-906
Stack Size (inches) | Maximum Length (feet) | Maximum Fixture Units | Maximum Water Closets | Maximum Fixture Units on a Branch Interval
1¼ | 45 | 1 | 0 | 0
1½ | 60 | 3 | 0 | 0
2 | 75 | 16 | 0 | 8
2½ | 105 | 32 | 0 | 16
3 (See Note 3) | 150 | 60 | 3 | 32
4 | 225 | 240 | 24 | 72
5 | 300 | 600 | 48 | 144
6 | 400 | 1,000 | 96 | 288
8 | 600 | 3,675 | 300 | 576
10 | N/A | 5,400 | N/A | 702
12 | N/A | 8,400 | N/A | 1260
Fixture loads on branch lines are based on one-fourth inch per foot slope.
Note 1: Maximum length shall be the developed length of any soil or waste line from its originating point to the last fixture opening.
Note 2: A branch shall be any soil or waste line not vented full size.
Note 3: Maximum of three clothes washers.
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(Ord. No. 40524, § 1, 10-20-15; Ord. No. 42654, § 34, 8-13-21)
Omaha Municipal Code § 49-907 Soil and waste systems located below the building sewer or public sewer.
Sec. 49-907. - Soil and waste systems located below the building sewer or public sewer.
When all or part of the building drainage system cannot be drained by gravity to the building drain, building sewer, private sewer or city sewer, the following requirements shall apply:
(a) Lifting equipment and piping shall be considered part of the plumbing system.
(b) The soil and waste systems shall discharge into an airtight sump or receiving tank located to receive the sewage by gravity.
(c) Soil, waste and vent piping for fixtures discharging into the sump (or receiving tank) shall comply with gravity system requirements.
(d) The discharge piping shall be no smaller than the connection on the pump/equipment and all pipe and fittings shall be pressure rated for 1½ times the maximum head pressure rating of the pump.
(e) The waste fixture unit rating is based on the gallons per minute discharge of the pump according to Table 49-907(e) below:
Table 49-907(e)
Discharge (G P M) | Load Fixture Units | Discharge (G P M) | Load Fixture Units | Discharge (G P M) | Load Fixture Units
3.0 | 1 | 18.4 | 17 | 52.5 | 140
5.0 | 2 | 18.8 | 18 | 57.0 | 160
6.5 | 3 | 19.2 | 19 | 61.0 | 180
8.0 | 4 | 19.6 | 20 | 65.0 | 200
9.4 | 5 | 21.5 | 25 | 70.0 | 225
10.7 | 6 | 23.3 | 30 | 75.0 | 250
11.8 | 7 | 24.9 | 35 | 80.0 | 275
12.8 | 8 | 26.3 | 40 | 85.0 | 300
13.7 | 9 | 27.7 | 45 | 105.0 | 400
14.6 | 10 | 29.1 | 50 | 124.0 | 500
15.4 | 11 | 32.0 | 60 | 170.0 | 750
16.0 | 12 | 35.0 | 70 | 208.0 | 1,000
16.5 | 13 | 38.0 | 80 | 238.0 | 1,250
17.0 | 14 | 41.0 | 90 | 269.0 | 1,500
17.5 | 15 | 43.5 | 110 | 297.0 | 1,750
18.0 | 16 | 48.0 | 120 | 325.0 | 2,000
(f) All discharge piping shall be labeled "Pressure Waste Line" and no other waste shall be connected to this line.
(g) The system shall be connected to the building drain or building sewer with a full flow check valve and gate or full flow ball valve installed in the discharge line no higher than five feet above the top of the sump or tank.
(h) The airtight sump or receiving tank shall be vented accordingly:
(1) The sump shall be vented according to the manufacturer's recommendations, but no less than 1½ inches.
(2) The vent pipe size is based on the waste fixture unit and the length of the vent pipe in accordance with section 49-1313.
(3) The sump vent may be connected to the building venting system.
Exception: Soil and waste system discharged through a pneumatic ejector the vent for the sump or receiving tank shall be run independently of other vents.
(i) A sump or receiving tank is not required to be airtight or vented when a sub-drain receives discharge from a single basement floor drain only or residential clothes washers.
(j) A macerating toilet system may be permitted as an alternate to a sewage pump system when used for a single bathroom or restroom when in the opinion of the chief plumbing inspector the bathroom or restroom cannot be installed using a gravity system.
(Ord. No. 40524, § 1, 10-20-15)
Omaha Municipal Code § 49-908 Subsoil drains commercial.
Sec. 49-908. - Subsoil drains commercial.
The following provisions shall be observed regarding subsoil drain installation in commercial buildings or premises:
(a) Exterior drains may be installed by a licensed sewer layer.
(b) Interior drains shall be installed by a licensed master or journeyman plumber.
(c) Drains shall be installed in a suitable porous bedding material along with a filter fabric to prevent clogging.
(d) Material for subsoil drainage shall meet the specifications stated in section 49-834.
(e) A sump pump pit shall be a minimum 20 inches diameter and 36 inches deep. Sump pump pits do not require airtight covers.
(f) When the discharge for a sump pump connects to a storm or a combination sewer, it shall have a full flow check valve and gate or full flow ball valve installed in the discharge line no higher than five feet above the top of the sump or tank.
(g) A subsoil drain connected by gravity to a storm sewer (or the building storm drain) shall have a back water valve installed at (or before) the connection. The valve shall be located in a minimum 48-inch manhole.
(h) A back water valve will not be required if the gravity subsoil drain discharges to a grated inlet that has an overflow rim with a lower elevation than the invert of the subsoil pipe.
(Ord. No. 40524, § 1, 10-20-15)
Omaha Municipal Code § 49-909 Subsoil drains single family residential.
Sec. 49-909. - Subsoil drains single family residential.
For single family dwellings, all exterior discharge piping shall require a permit to ensure compliance with article XVII and the following criteria.
(a) No water from a subsoil system shall be permitted to discharge into the sanitary sewer.
(b) No discharge from the sump pumps shall create a nuisance.
(c) No water from a subsoil system shall be permitted to flow over public sidewalks, streets or adjacent property.
(d) Any discharge from sump pumps shall discharge at least three feet away from the building foundation.
(e) If the pump's discharge cannot be piped in such a manner as to avoid the flow of discharged water onto sidewalks, driveways, parking lots, streets or onto adjacent property, the discharge must be piped and directly connected to a storm sewer. If a storm sewer is not available to the property, the property owner may request the public works department's permission to take the discharge to the street at the gutter.
(Ord. No. 40524, § 1, 10-20-15)
Omaha Municipal Code § 49-910 Sump discharge for elevator pits.
Sec. 49-910. - Sump discharge for elevator pits.
Sump pumps located in elevator pits shall be discharged to the sanitary plumbing system by indirect waste to an approved receiving fixture. The sump or receiving tank is not required to be airtight or vented.
Where an elevator hoistway pit sump pump system is required to provide more than 50 gallons per minute flow, the sump pump system may utilize multiple pumps to provide the total required flow. The first stage pump shall provide a minimum of 30 gallons per minute and shall discharge to the building sanitary sewer system at a stand pipe (site drain) or other approved fixture. See Table 49-1014 for allowable flow rates of approved receiving fixtures. (See Figure 49-910.)
Additional pumps shall be configured to operate only if the first pump cannot remove the water in the hoistway pit and shall be allowed to discharge to a building parking garage drain system if available. If the additional pumps discharge to the parking garage drain system, the parking drain system must be sized to accommodate the flow from the additional pumps.
If a parking garage drain system is not available, the additional pumps shall be allowed discharge to either building sanitary sewer system at an approved fixture or to grade outside the building provided that accommodations are made so the pump(s) does not discharge onto adjacent property or onto sidewalks, driveways, parking lots or streets causing a nuisance.
Discharge from multiple stage elevator sump pumps shall be reviewed and approved by the chief plumbing inspector.
No waste or vent piping shall be located within the elevator shaft.
(Ord. No. 40524, § 1, 10-20-15)
Omaha Municipal Code § 49-911 Wastewater pumping system for gray water fixtures.
Sec. 49-911. - Wastewater pumping system for gray water fixtures.
When the chief plumbing inspector determines a fixture cannot be installed using a gravity system, a sump may receive the discharge. The following installation provisions shall be observed for both single fixture and group fixture situations (except as stated in subsection (e)):
(a) The sump shall be installed above the floor.
(b) Shall have a maximum 1½-inch inlet and 1½-inch discharge. The waste fixture unit rating shall be based on the gallons per minute discharge of the pump according to Table 907(e).
(c) The cover shall have a gas-tight seal.
(d) Shall discharge gray water only.
(e) Single fixture: The sump shall be vented according to the manufacturer's recommendations, but no less than 1½ inch. The vent pipe size shall be determined according to section 49-1313.
Fixture group: Waste and vent piping for fixtures discharging into the sump or receiving tank shall be installed in accordance with the requirements for a gravity system.
(f) The sump vent may be connected to the building venting system.
(g) Pumping equipment and piping shall be considered part of the plumbing system. Discharge piping shall be labeled "Pressure Waste Line". No other waste shall be connected to this line.
(h) A full flow check valve and gate valve or full flow ball valve shall be installed in the discharge line no higher than five feet above the top of the sump or tank.
(Ord. No. 40524, § 1, 10-20-15)
Source: City of Omaha, Municipal Code and City Charter (Municode Library, library.municode.com)URL: https://library.municode.com/ne/omaha/codes/code_of_ordinances?nodeId=OMMUCOCHGEORVOII_CH49PL_ARTIXSOWAPI_DIV1GEFetched: 10/28/2026