Inspecting the Septic System Before Buying the House

More than one-third of the homes in the southeastern United States depend on septic systems for their waste water treatment, including more than half a million homes in Virginia and almost half the homes in North Carolina. If you own a home with septic system or plan on buying a home with a septic system you need to understand how they operate and how to maintain them.

Buying a home is probably the biggest purchase you will ever make, so you want to avoid unknowingly buying someone else’s’ problem or at least not knowing that a septic system is not working properly. A septic system has a limited life, is expensive to repair and can cost $15,000-$40,000 to replace so you want it to be in good condition when you buy the home and keep it in good repair as long as possible.

Before you purchase a house you have the system inspected by a licensed septic system service provider. Home inspections do not cover septic and well systems. The average lifespan of a septic system is 15 to 40 years, but it can last longer if properly maintained! A traditional septic system should be inspected every three to five years by a septic system service provider; and an alternative septic system (called an AOSS) must be inspected at least every year in Virginia.

The septic tank in all types of systems should be pumped as recommended by the service provider or as required by your locality. Here in Prince William County it is required to be pumped at least every five years; however every three years is better. Pumping more frequently will extend the life of your system and protect the environment.

A professional septic system inspection should include reviewing :

• Pumping and maintenance records (now available online for registered inspectors from the Virginia Health Department system, VDH); 
• The age of the septic system and general condition of the system and soils. (They typical life of a system is 15-40 years and you want to know how close you might be to needing to replace the system); 
• Sludge levels and scum thickness in the tank; 
• Signs of leakage, such as low water levels in the tank; 
• Signs of backup, such as staining in the tank above the outlet pipe or dark sediment in household toilets; 
• Integrity of the tank, inlet, and outlet pipes; 
• The drainfield, for signs of system failure like standing water or surfacing sewage; (Note that in Fairfax and some other localities it is common to have two drainfields that are rotated every 6 months. Check them both.) 
• The distribution box should be checked to make sure drain lines are receiving equal flow; and 
• Available records at the VDH district office should be checked, to make sure the system complies with local regulations regarding function and location and was certified. 

The following is from the U.S. EPA brochure “New Homeowners Guide to Septic Systems” 

from US EPA

How a septic system works:

1. All water runs out of your house from one main drainage pipe into a septic tank. 
2. The septic tank is a buried, water-tight container. Its job is to hold the wastewater long enough for bacteria to breakdown the solids and for the solid waste to settle to the bottom of the tank as sludge while the fats, oil and grease float to the top as scum. 
3. For conventional septic systems, liquid wastewater exits the tank either by pumping or gravity and is spread evenly throughout the drainfield, usually through a distribution box also called a “zoner.” Systems with more advanced treatment have an additional treatment step like an ATU tank, a peat tank, nitrogen removal system between the septic tank and drainfield. 
4. Once in the drainfield, the wastewater percolates into the soil, which reclaims the water for future reuse by naturally removing harmful bacteria, viruses, and some nutrients. 

These processes may vary based on the site, conditions of the property and design of the septic system installed. In Virginia there are approved septic treatment systems and custom design systems that must meet all the same standards. A DPOR licensed septic system service provider and your septic system’s “as built” drawings will be able to tell you what type of system is on the property. For approved AOSS systems the manual for the system is available online. Read it!