I just did that test myself a couple weeks ago, and came up with the same result. Usually it was a crummy plastic bung for the vent hold that would leak. The Coleman and the Aqua-Tainer worked fine though. I prefer the 4 gallon aqua-tainer for 2 reasons- it's squat so it won't tip over on the floor of my mini-van, and it's stackable in case I decide to get more.