Quantities of Domestic Flow Rates
The following flow rates shall be used for the design of Onsite Wastewater Treatment Systems (OWTS). Any rate determined to be more than 3,000 gallons per day shall be designed, permitted, and inspected in accordance with the requirements of the Missouri Department of Natural Resources (MoDNR).
| Establishment | Minimum Design Flow Rate (in gallons per day) | Design Flow Rate Calculation (in gallons per day) |
|---|---|---|
Residential Facilities |
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| Single-Family Residential Dwellings | 240 GPD | The greater of 120 GPD per bedroom or 60 CPD per occupant |
| Multi-Family Residential Dwellings (with laundry) | 120 GPD | 120 GPD per bedroom |
| Multi-Family Residential Dwellings (without laundry) | 100 GPD | The greater of 95 GPD per bedroom or 50 GPD per occupant |
| Mobile Homes | 300 GPD | 300 GPD per unit |
Commercial Facilities |
||
| Transportation Terminals (including airports, bus stops, railroad stations, etc.) | 100 GPD | 5 GPD per passenger |
| Laundromats | 580 GPD | 580 GPD per machine |
| Beauty Shops | 125 GPD | 125 GPD per chair |
| Bowling Lanes | 100 GPD | 50 GPD per lane |
| Businesses (not in table) | 100 GPD | 25 GPD per employee |
| Factories without Showers* | 100 GPD | 25 GPD per person per shift |
| Factories with Showers* | 100 GPD | 35 GPD per person per shift |
| Marinas without Bath Houses | 100 GPD | 10 GPD per boat slip |
| Marinas with Bath Houses | 100 GPD | 30 GPD per boat slip |
| Hotel/Motel without Cooking Facilities | 120 GPD | 120 GPD per room |
| Hotel/Motel with Cooking Facilities | 175 GPD | 175 GPD per room |
| Offices | 100 GPD | 25 GPD per person per shift |
| Service Stations (<24 hours) | 250 GPD | 250 GPD per water closet or urinal |
| Service Stations (24 hour) | 325 GPD | 325 GPD per water closet |
| Movie Theater (Seated) | 100 GPD | 5 GPD per seat |
| Movie Theater (Drive-In) | 100 GPD | 15 GPD per vehicle space |
| Warehouse | 100 GPD | 30 GPD per employee |
| Public Park (Toilet Only) | 100 GPD | 5 GPD per user |
| Public Park (with Bath House) | 100 GPD | 15-25 GPD per user |
Camps |
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| Construction or Work Camps | 100 GPD | 60 GPD per person |
| Construction or Work Camps (with Chemical Toilets) | 100 GPD | 40 GPD per person |
| Summer Camps | 100 GPD | 60 GPD per person |
| Campgrounds with Comfort Stations (no water or sewer hookups) | 100 GPD | 100 GPD per campsite |
| Travel Trailer/RV Park (with water and sewer hookups) | 120 GPD | 120 GPD per space |
Assembly and Mercantile |
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| Retail Stores | 120 GPD | 120 GPD per 1,000 sq. ft. of retail sales space |
| Stadium, Auditorium, Theatre | 100 GPD | 5 GPD per seat or space |
| Swimming Pools, Spas and Bath Houses | 100 GPD | 10 GPD per person |
| Churches (not including a Kitchen, Food Service Facility, Daycare or Camp) | 100 GPD | 3 GPD per seat |
| Churches (including a Kitchen but not Food Service Facility, Daycare or Camp) | 100 GPD | 5 GPD per seat |
| Country Club | 100 GPD | 20 GPD per member |
Food and Drink Establishments** |
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| Bar (Not Serving Food) | 100 GPD | 20 GPD per seat |
| Restaurant (<24 hour) | 100 GPD | Greater of 40 GPD per seat or 40 GPD per 15 sq. ft. of dining area*** |
| Restaurant (24 hour) | 100 GPD | 75 GPD per seat*** |
| Food Stand | 100 GPD | 50 GPD per 100 sq. ft. of area plus 25 GPD per employee*** |
| Other Food Service Facilities | 100 GPD | 5 GPD per meal*** |
| Meat Market | 100 GPD | 50 GPD per 100 sq. ft. of area plus 25 GPD per employee*** |
Institutional** |
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| Hospitals | 300 GPD | 300 GPD per bed*** |
| Daycare Facilities | 100 GPD | 15 GPD per person |
| Residential Care Facilities | 100 GPD | 60 GPD per person*** |
| Rest Homes and Nursing Homes (with Laundry Facilities) | 120 GPD | 120 GPD per bed*** |
| Rest Homes and Nursing Homes (without Laundry Facilities) | 100 GPD | 60 GPD per bed*** |
| Day Schools (with Cafeteria, Gym and Showers) | 100 GPD | 15 GPD per student*** |
| Day Schools (with Cafeteria only) | 100 GPD | 12 GPD per student*** |
| Day Schools (without Cafeteria or Showers) | 100 GPD | 10 GPD per student |
| Boarding Schools | 100 GPD | 60 GPD per student |
*Factories producing industrial waste are regulated by the Missouri Department of Natural Resources (MoDNR).
**Establishments processing food may be required to provide grease interceptors in an accessible location prior to the OWTS.
***Food service operation facilities shall have flows multiplied by 1.5 times to accommodate the high organic strength of the waste. (This multiplier is not used to determine jurisdiction related to the 3,000 gallons flow rate.)