Schematics for water line

I got the schematics for the waterlines however I'm a little freaked out because the waterlines in the kitchen go along the wall then under the refrigerator from there evidently they go down some unseen hole and between the plywood and the holding tanks over to the bath, and pump. They can not be seen from under the rig, and I do not see any removable plywood panels in the floor ......
Soooooo.... Does anybody know a secret to get past this hidden area ?
If not! I might talk myself out of this job. Lol.
Thanks again for any input and help...