During the site evaluation of a lot, a test pit should be located and dug

• A. at the location of the proposed leaching bed
• B. at the entrance of the lot
• C. near the boundary
• D. near the street curb

Answer: (A)

When evaluating a lot for an onsite system, you need accurate information about the soil where the effluent will actually be dispersed. A test pit is dug at the location of the proposed leaching bed because that’s the area that will determine how well the soil can accept and transmit wastewater. By digging there, you uncover the soil profile, texture, depth to any restrictive layers, and the infiltration rate right where the leach field would be installed. Soil conditions can vary across a site, so testing elsewhere—at the entrance, along the boundary, or near the street curb—could misrepresent the capacity of the leach field and lead to a design that doesn’t perform or comply with regulations. Knowing the true conditions at the leach bed helps size the system correctly and ensures it will drain properly within required setbacks and design parameters.