I did a DIY water project once to avoid the intrusive building
inspection dept.

.......................................BIG MISTAKE
the contractor I hired only installed the corrugated drain pipe on TOP
of the footer, and didnt backfill to my specs, which were all gravel
where a sidewalk was being replaced.... so the new sidewalk wouldnt
crack

I fired the original contractor and ended up paying for the same job
twice contractor 2 noted the pipe on top of the footer, it should of
been a little below it so underground water wouldnt percolate up thru
the basement floor. well I was out of $ so left it as is, he only redid
part of the job.

that fall the basementy flooded again and I was forced to spend 6 grand
on interior french drain.

If I had used the building inspector I might have paid a bit more for
the initial job but would oif saved contractor 2 and 3 who did the
interior waterproffing...

lessons learned with a big job those rules are there for a reason.....

on this fellows house, if he is only trying to keep a crawl space dry
why dig down 10 feet deep, a couple feet may be all thats necessary....

a 10 foot deep execvation close to the property line may well cause
settling or collapse of his neighbors property, house, driveway,
sidewalks may sink settle and crack. $ liability for repairs

probably better to surround crawl space with a 3 foot deep trench with
drainpipe on bottom landscape cloth to prevent pipe clogging and
backfilled with mostly gravel landscape cloth over top covered by a
foot of topsoil, having one or two leads going under home to redirect
any water pooling under home, cover crawlspace with 10 mil overlaped
poly sealed with tape, provide lots of vents under home so moisture
cant accumulate

the goal is not have water under home, what happens 5 or 10 feet down
really doesnt matter, in many areas thats the water table.