I myself have had to so through the process and my inspector was very good. But being a licensed plumber I know that he just looked at the cosmetics of the plumbing fixtures around the home. Not the plumbing underground that is where the most expensive damage can hide.
For homes with septic systems it is almost a requirement to get the septic tank professionally inspected by a certified septic inspector.
What I find is that there are no requirements for main sewer lines to get inspected before the closing on the home.
I have come across many situations after the new home owner moves in they quickly develop sewer drainage problems and drains being constantly clogged.
It is a good idea to hire a licensed plumber that can do an additional plumbing and drain inspection on a home before closing. Plumbing and drain problems can cost from thousands to tens of thousands of dollars to fix properly, and are missed by the home inspectors because they are not required to check the insides of drains and main sewer lines.
YARO Plumbing has the experience and equipment to do a thorough inspection of a home for problems with the plumbing systems above ground and below. And also give you a diagnostic of the current condition of the piping and fixture that may be on their last leg.