Drain Field Size Calculator

Formula

To calculate the Drain Field Size (DFS):

\[ DFS = \frac{DF}{AR} \]

Where:

\(DFS\) is the Drain Field Size (square feet)
\(DF\) is the Daily Flow into the Septic System (gallons per day)
\(AR\) is the Absorption Rate of the Soil (gallons per day per square foot)

What is Drain Field Size?

Drain field size is a critical component of a septic system, determining the area necessary to properly filter and treat wastewater as it percolates through the soil. The size of the drain field is influenced by the daily flow of wastewater and the soil’s absorption rate. Proper sizing is essential to prevent system failure and environmental contamination.

Example Calculation

Let's assume the following values:

Daily Flow (\(DF\)) = 500 gallons per day
Absorption Rate (\(AR\)) = 0.5 gallons per day per square foot

Using the formula:

\[ DFS = \frac{500}{0.5} = 1000 \text{ square feet} \]

The Drain Field Size is 1000 square feet.