Your first opportunity for this achievement is in the Second Biome - Floor 3 - Level Door 6 of the Campaign.
There is a "pool" in this level that circles the entire level
(it's more like a lazy river in this case) in any case you will see a few of the needed supplies to complete the level. I have not tested this but I think if you climb into the water via the ladder and grab the supplies you may not get the achievement, If someone can test this I will update this part. So instead stand on the patio near the water and pick up any/all the items as they float by by pressing
. The achievement will pop right away.
Another note I did notice on this level that if you do not see the Items in the water check the top left corner of the pool because I did have a case where the rug got wedged on the corner and blocked all the other paint cans and such from flowing around.
If you have a 2nd controller or a friend playing you can also get the achievement for "Falling into water" here just have the other player pick your character up with
and throw you in with
