Wyoming Administrative Code
Agency 020 - Environmental Quality, Dept. of
Sub-Agency 0011 - Water Quality
Chapter 25 - SEPTIC TANKS, SOIL ABSORPTION SYSTEMS, AND OTHER SMALL WASTEWATER SYSTEMS
Section 25-5 - Design Flows
Current through September 21, 2024
The volume of wastewater shall be determined by one of the following:
(a) Tables 1 and 2 provided in this section.
(b) Metered water supply data from the facility.
(c) Metered water supply data from another facility where similar water demands have been demonstrated.
Table 1. Residential Design Flow Rates per Bedroom (gallons per day, gpd)1
| 1 bedroom | 150 |
| 2 bedrooms | 280 |
| 3 bedrooms | 390 |
| 4 bedrooms | 470 |
| 5 bedrooms | 550 |
| 6 bedrooms | 630 |
1An unfinished basement is considered two (2) additional bedrooms.
2The design flow shall be increased by eighty (80) gpd for each additional bedroom over six (6).
Table 2. Non-Residential Wastewater Design Flow Rates1
| Facility | Unit | Flow (gallons/unit/day) |
| Airports | person | 4 |
| Apartment | bedroom | 120 |
| Automobile Service Station | vehicle served | 10 |
| Bars | seat | 20 |
| Bathhouses and swimming pools | person | 10 |
| Campgrounds (w/ toilets only) | person | 25 |
| Campgrounds (w/shower facility) | person | 45 |
| Church | person | 4 |
| Country Club | member | 25 |
| Day School, Office Building, Retail Store, Warehouse (no showers) | person | 15 |
| Hospital | bed | 250 |
| Industrial Building (sanitary waste only) | employee | 20 |
| Laundry (self-service) | machine | 450 |
| Mobile Home | bedroom | see table 1 |
| Motel, Hotel, Resort | bedroom | 140 |
| Recreational Vehicle | each | 100 |
| Rest Home, Care Facility, Boarding School | bed | 100 |
| Restaurant | meal | 10 |
| Restaurant ( kitchen waste only) | meal | 6 |
| Theater | seat | 3 |
1Values shown in the above table are the typical flow rates from Wastewater Engineering Treatment and Reuse, Metcalf and Eddy, 2003.
