What is a Title V Certificate?

The 40 year old property we want to purchase has a Title V Certificate. What does that mean?

The Title V certificate is the septic equivalent of a home inspection. The septic system was located and assessed according to specific criteria. Although the system is forty years old, it works well at the time it was inspected. Septic systems typical lasted 25- 40 years and I would expect to repair or upgrade this system within the next few years.