If you are buying a house with a septic system, you need to have that system inspected to make sure you are not buying a problem that could cost you thousands or even tens of thousands of dollars to fix. Septic inspections are excluded from the standard home inspection, and Virginia is a buyer beware state with regards to septic systems and wells. So, you need to take care to make sure that the septic system has been properly maintained, not at the end of its useful life and is operating properly. Have any necessary repairs made to the system before closing or you are out of luck.
There are two basic types of septic systems- conventional and alternative. Site, soil conditions and age determine the type of system that was installed. A conventional system consists of a single chamber septic tank and drain/leach field with the related piping. The tank receives the wastewater from the house and allows the solids to settle down to the bottom of the tank where the anaerobic bacteria that live in the tank digest the organic materials while the effluent (water around all that stuff) flows out to the leach field to be purified by passing through soil until it reaches the groundwater. Scum consisting of oil and grease floats on top of the water layer in the tank and if the tank is too full can be pulled into the leach field limiting its effectiveness and clogging the leach field. In the the leach field the effluent it percolates into the soil, which provides final treatment by removing harmful bacteria, viruses, and nutrients. In many cases the components of a septic system are not visible from the surface, but their proper installation and location should be documented at the local health department office.
Other types of septic systems are grouped together and called alternative on-site sewage systems, AOSS. All alternative systems have a secondary treatment system. One example of an AOSS is an aerobic system consists of a multi chamber tank or several tanks. After separation of solids in the first tank waste is forced through a filter into a second chamber or tank where air is pumped in to enhance aerobic bacteria which decomposes the organic material. The waste then flows into a third chamber or settling chamber which collects the bacteria and passes the liquid on to the leach field or drip field. Other type of AOSS include traditional septic tanks followed by treatment with tanks filled with peat, or sand mounds, or other soil absorption system that provide the secondary treatment. These types of secondary treatment tanks are visible in the yard. There are many different types of AOSS. The cost and type of maintenance, repair or media replacement is directly related to the components of the AOSS system. Peat modules can cost more than ten thousand dollars to replace each 10-15 years, while a blower on an aerobic tank can cost about a thousand dollars to replace every few years.
In Virginia all AOSS are required to have a licensed operator maintain the system and be inspected at least annually and are required to be sampled if the system was permitted after December 7th 2011. The septic tank or tanks should also be pumped regularly and the need for pumping assessed at each annual inspection. For more information on AOSS regulations and requirements see the Guidance Document from the Virginia Department of Health.
Having a septic tank pumped and alternative onsite sewage system maintained at appropriate intervals is as critical to keeping the system functioning properly and not polluting the groundwater. VDH recommends that the average household conventional septic system be inspected at least every three years by a septic service professional (licensed by the DPOR). However, alternative onsite sewage systems are required to be inspected at least annually by a licensed operator. Household septic tanks should be pumped every three to five years. Four major factors influence the frequency of septic pumping:
- Household size
- Total wastewater generated
- Volume of solids in wastewater (garbage disposal system)
- Septic tank size
Pump outs are legally required in some localities. In northern Virginia, pump outs are required at least every five years for systems located in Chesapeake Bay Preservation Areas (although some localities may accept an inspection report performed by a licensed or certified expert in lieu of a pump out). Compliance with the regulations for pump out and inspections has been poor. The most likely source of contamination to a drinking water well is a nearby septic system failure, and typically, the nearest septic system is your own. The homeowner is responsible for maintaining it.
If you are considering buying a home with a septic system you need to do two things:
- Have the system inspected by a licensed operator and septic service company to come out and inspect the operation and condition of the system. You should accompany them on the inspection to ask questions and hear their comments.
- Use the historical records to verify that the system was installed under permit from the health department, has been maintained and regularly inspected and the septic tank pumped regularly. All this information can be obtained from the local health department. Their electronic files will contain information on the original installation, the type of system that is on site and any permitted repairs. You can call the health department or make the realtor work and print out the information for you. Look over the file carefully. Also, the county maintains a list of the most recent recorded septic tank pump-out, and inspections for AOSS systems. If the home has an AOSS and it has not been regularly inspected, it is probably not working properly.