At a meeting of the Board of Supervisor's Public Safety Committee on February 27, 2006, the Loudoun County Public Health Department provided some initial data on the failure rates of septic systems in the county. According to the Health Department, during the three years between January 2003 and December 2005:

Conventional Septic System Failures:
• Total failures in the 3-year period is 71 or 24 per year
• Total installed systems: about 12,000
• Thus, the failure rate is 2/10 percent.
• Age at failure: 25 years or more.

Alternative Septic System Failures:
• Total failures in the 3-year period is 14 or 4.6 per year.
• Total installed systems: about 800
• Failure rate is 6/10 percent.
• Age at failure: 5 years or less.

So let's do the math. If the failure rate of alternative septic systems is three times higher than conventional systems in 1/5 the time, after 25 years (the life of conventional systems) the failure rate of alternative systems is 15 times that of conventional systems.

If the installed base of alternative septic systems were as large as the 12,000 traditional septic systems we have today, at the end of 25 years, instead of the 24 or so failures per year we are seeing with traditional septic systems, we would be seeing over 350 alternative septic system failures per year--and that would be a potential public health crisis of significant proportions.

The Health Department also said at the public meeting that current septic failures are under-reported in the county. It is no surprise that homeowners don't want to have failed septic systems recorded with the county. Actual failure rates, especially for the newer alternative septic systems with less of a track record, could actually be significantly higher.