First you were trying to destroy "evidence" throwing them in the water bowl, which of course is actually another crime into itself which you just confesed to HUMMM.
But yes residue is cooked or burnt onto the pipe and can be found long afterwards.
Now having the drugs in the car, and if you were riding in the car, ( if you confessed to them that you rode in the car their with them puts you in the car with the drugs.
In Georgia anyway, if there are 4 people in a group and one has drugs on them, all can be chanrged.
The charge for the pipes and other items will most likely stick, and they will most likely offer you a good deal if you testify against who the drugs actually belonged to.

