Capacities of horizontal building drains and building sewers.
Omaha Municipal Code § 49-903
in effectSec. 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)
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_DIV1GE_S49-903CAHOBUDRBUSEFetched: 10/28/2026