What should be done if limestone is known to be present during a soil test?

If limestone is known to be present during a soil test, it is crucial to test at least 4 feet deeper than the bottom of the trench. This practice is important because the presence of limestone can significantly affect the soil drainage and absorption capabilities, which are critical factors in the design and installation of a septic system.

Testing deeper allows the installer to identify the characteristics of the soil below the limestone and ensure that the septic system is situated in a suitable location for effective effluent treatment. It can also help determine the depth at which groundwater may be encountered, as limestone can impact groundwater flow and quality. By assessing those deeper layers, it ensures a more comprehensive understanding of how the septic system will interact with the surrounding environment, thereby enhancing the system's performance and longevity.

Other approaches may not adequately address the potential issues that limestone can introduce, making this deeper testing a necessary step in ensuring regulatory compliance and environmental safety.