|Flickr: Natty Dread|
It turns out that the Maryland Department of the Environment (MDE) does keep a list of individuals who have taken a one day course in OSDS inspections. I can use this list in conjunction with the list of installers licensed by the county to pare down the candidates for my inspection. I will look for local inspectors who aren't installers, because I think there could be a conflict of interest that would push an inspector/installer to fail your system in the hope of getting some big ticket repair work.
Either way, the inspector to hire is someone who follows the recommendations of MDE on how to conduct inspections. They should also use a checklist like the one published by MOWPA. Screening on the phone should include finding out whether they dig to uncover the distribution box and drain tiles. It will be interesting to find out how many of the inspectors listed by MDE as trained actually measure up.