I kept hearing a sloshing sound in my 2009 Odyssey when driving and just figured it was gas in the tank. Then I remembered something from my teenage car fixin' days and checked the weep holes under the driver side sliding door which isn't used much. As soon as the door opened I could hear the sloshing. Stuck a 2 1/2 gallon bucket under the door and poked just one of the weep holes with a small screwdriver. Almost 2 gallons of water poured out.
A lot of those cars you see with the bottom of the doors rusted out fell victim to this.