alcona, a soil percolation test is a test performed to determine the rate at which water percolates through the soil. The test is required by many health department ISDS regulations to determine if the soil on a specific site is suitable for use as a soil absorption system media.
The “Perc Rate” is reported in terms of Minutes per Inch; the time interval required for a column of water to drop 1 inch in the perc test hole. The perc rate, and the estimated maximum daily flow volume are typically used in a mathematical sizing formula to determine the required size of the soil absorption system.
If a public sewer is serving this property, then there is no need for a soil absorption system, nor a soil percolation test.
In most jurisdictions, the estimated maximum daily flow of sewage is based upon the number of bedrooms there will be in the home being served. Most regulations estimate that there will be 2 people per bedroom, and each person will generate a maximum of 75 to 112.5 gallons of sewage per day. The maximum daily flow estimate varies depending upon the jurisdiction.
So, to answer your last question, the number of bedrooms, not the size of the house is the determinant of the area of the soil absorption system. JWA