If you hit a larger boulder than can be removed while digging a hole for a septic tank, what is the best action to take?

Filling the hole with tamp gravel and sand to raise the septic tank is the best action to take in this scenario. This approach allows the tank to be installed at the correct elevation needed for proper drainage and functionality while also providing stability. Gravel and sand are good materials for this purpose as they are well-draining, which helps prevent water from pooling around the tank and promotes proper septic system function.

Opting to install the tank deeper may not be advisable, as this could complicate matters with drainage and potentially push the tank below the necessary level for effective operation. Additionally, filling the hole with tamped soil can lead to compaction issues, which might not support the tank adequately over time, risking future system failures or damage. This is why utilizing gravel and sand to create a stable base is the preferred method for addressing the obstacle of a larger boulder.