The first Plumbers' Badge is on the ledge that you float up to as Big Chill. After floating up, turn around and you will see it in a green orb guarded by some ground spikes. Break the orb to collect the Plumbers' Badge.
The next one is to the right of the bone door after the Echo Echo bridge puzzle. It is encased in another green orb. Smash the orb and collect the Plumbers' Badge.
There is another Plumbers' Badge in a green orb on the floating platform. It is located to the right of the rotating spike loop. Destroy the green orb to collect the Plumbers' Badge.
The next Plumbers' Badge will be in the Cannonbolt tunnel. There is a 'Y' intersection that prompts you to go left. Follow that tunnel and you'll roll into the Plumbers' Badge.
The final Plumbers' Badge of the level is to the right when making your way across the multitude of square floating platforms. Just go all the way to the far right platform and it will be sitting there.