What might happen if a septic tank is pumped during a wet period?

If a septic tank is pumped during a wet period, it can become buoyant due to water saturation in the surrounding soil. When the ground is excessively saturated, the groundwater level rises significantly. In such conditions, an empty septic tank may lose its stability and can float upwards if the pressure of the groundwater exceeds the weight of the tank. This phenomenon is similar to how a boat floats in water; if the buoyant force becomes greater than the weight of the tank, it can rise or float out of its intended position. This can lead to significant damage to the septic system, requiring repairs and potentially creating environmental hazards.

Understanding this concept highlights the importance of timing when pumping septic tanks, particularly with respect to local weather conditions and the moisture content of the soil.