Table 1. Estimated sewage flows in gallons per day

Number
of bedrooms		 Type
I		 Type
II		 Type
III		 Type
IV		  
2 300 225 180 60% of
the values
in Type I, II,
or III
columns
3 450 300 218
4 600 375 256
5 750 450 294
6 900 525 332
7 1050 600 370
8 1200 675 408

Type I: The total floor area of the residence divided by the number of bedrooms is more than 800 square feet, or more than two of the following water-use appliances are installed: automatic washer, dishwasher, water softener, garbage disposal, or self-cleaning furnace.

Type II: The total floor area of the residence divided by the number of bedrooms is more than 500 square feet, and no more than two water-use appliances are installed.

Type III: The total floor area of the residence divided by the number of bedrooms is less than 500 square feet, and no more than two water-use appliances are installed.

Type IV: Type I, II, or III homes but with no toilet wastes discharged into the sewage system.

Onsite Sewage Treatment Manual, University of Minnesota Extension Service, 1998, St. Paul.

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