French drain design

If the tree isn't in the way, build a swale from the backyard sloping down to the street on the left side of the house. This assumes the street is lower than the areas that are flooding. If the tree IS in the way, start the swale near the left front wall of the house, ending at the street. A swale is a sort of ditch, just much wider and much shallower. It facilitates rainwater drainage without sacrificing curb appeal. Constructed properly, you'll hardly notice it when the grass has returned. The best litmus test for inspector expertise is the reports the inspector has written. Nothing else comes even close. Download and do a 3 minute review of a few dozen sample reports from anywhere in the country. That'll teach you what a good report, and good inspector, looks like. Then look locally for your inspector. Good luck..the good ones are few and far between, like...fewer than one in thirty.

source https://www.inspectorsjournal.com/topic/18906-french-drain-design/?do=findComment&comment=172664