The Virginia Health Department has a great article on preventative action. The key points are outlined below. For a complete read, visit their article.
Preventative Action Avoids Headache and Frustration.
When facing a major storm or hurricane, your first priorities are to assure the safety of your family. Included in those priorities are concerns about safe drinking water and proper sewage disposal. Below are some concerns about private wells and onsite sewage systems when Virginia faces major storms or flooding.
If your home is served by a well, the well pump will not work when the power goes out. Toilets can be flushed by pouring a bucketful of water either into the tank and using the handle, or by pouring a bucketful into the bowl.
Onsite sewage systems may also fail to operate properly during a power outage. Pumps won't work without power, but most onsite sewage systems with a pump should have 100-200 gallons storage capacity above the high level alarm. Exceeding this storage capacity could cause the pump chamber to overflow, spilling raw sewage on the ground. Use water sparingly.
Many alternative systems also have electrical components such as aerators, flow control switches and other equipment. Many alternative systems also include a pump and therefore should have a limited amount of storage capacity as noted above. Alternative system owners should call their licensed Alternative Onsite Sewage System Operator as soon as possible once the power returns if some components do not seem to be functioning properly.
People who rely on private wells for their water should consider their well contaminated if it was submerged or they believe it is possible the well became submerged during the hurricane.
If the well was flooded and underwater, do not turn on the pump until you are sure the electrical system is completely dried out. Consider a well that has been submerged contaminated and disinfect the well and the water system using this procedure once you are sure the electrical system is safe.
The water should not be consumed until bacteriological testing indicates the well is not contaminated. Two satisfactory bacteriological tests performed on samples taken at least 24 hours apart will indicate your water supply has been properly disinfected. Labs certified to test drinking water are available HERE.
Onsite Sewage Systems
For any type of onsite sewage system, conventional or alternative, a hurricane or flood could submerge the system, causing a backup of sewage into the house. Look for sewage backups in the plumbing fixtures at the lowest elevations in your house.
Flooding can wash soil away from the septic tank, drainfield lines or other components, causing damage to the components or introducing raw or partially treated sewage into the yard. Flooding may also cause the onsite sewage system to operate sluggishly because the soil in the dispersal area is saturated.
If your septic tank/drainfield system is damaged by the storm or if the soil is saturated, minimize water use within the house to prevent raw sewage from discharging to the ground surface. Minimize contact with sewage contaminated waters. Use gloves and protective gear and wash any exposed skin with soap and water as soon as possible. Disinfect any exposed human contact surfaces with diluted bleach water.