Spring flooding can raise havoc with onsite wastewater systems.  Surface water can cause unweighted tanks to float and surface if they are not buried deeply enough.  If risers or cover s are loose or there are any fine cracks, water can seep into the tank and flood the tank, forcing both fluids and solids out into the field, saturating the system and clogging orifices.

There are ways to reduce the risk of system damage due to flooding.  Tanks should be weighted and secured and buried at an appropriate depth to reduce the possibility of floating.  Lids, risers and connections should be watertight.  High level alarms can be installed to let the homeowner know if the tank is overloaded from possible groundwater seepage. 

If it appears the system is being impacted by flooding, reduce the use of the system immediately.  Have the tank pumped if it is full and when it has been pumped have it inspected for cracks.  Entering the tank to inspect it requires someone trained in confined space entry.  Do not enter the tank without the proper training and safety gear.  Effluent is dangerous to the public health.  If effluent is surfacing on the property, avoid contact, fence or cordon the area off until the septic system can be properly repaired.