Use a plastic bag (or plastic box) inside to prevent water from reaching your cargo.

Untreated canvas tents don't leak water,... until you touch them. Then you can develop a spot leak. Water can also soak through into anything touching the inside walls.

If you do not water proof the outside, the canvas will absorb water and become very heavy.

Treated or not, any water that gets inside will have a hard time getting back out.


If you insist on using them when it rains, look into water proofing materials like Nik Wax, Otter Wax or other non-greasy treatments.