The Plumber Headquarters is a location that appears in Ben 10: Alien Swarm and Ben 10: Omniverse. It is a functional Plumber Base, lead by the Magister of Earth, Max Tennyson. One of the known entrances is through the Max's Plumbing shop bathroom.
It re-appeared in The More Things Change: Part 1, when Ben visited his grandfather, Max.
It was invaded by Dr. Psychobos and his robots. After the Omnitrix malfunctioned, some prisoners were transformed into some of Ben's aliens. The prisoners tried to escape from the prison, but were defeated by Ben, Rook and their team and were sent back to their cells.
- Ben 10: Alien Swarm (first appearance)
- The More Things Change: Part 1 (first re-appearance)
- The More Things Change: Part 2
- A Jolt From The Past
- Trouble Helix
- Have I Got A Deal For You
- It Was Them
- So Long, And Thanks For All The Smoothies
- Of Predators And Prey: Part 1
- Blukic And Driba Go To Mr. Smoothy's
- Arrested Development
- Ben Again
- Store 23
- Showdown: Part 2
- The Frogs Of War: Part 1
- The Frogs Of War: Part 2
- Evil's Encore
- Food Around the Corner
- Mud is Thicker than Water
- The Ultimate Heist
- Max's Monster
- Something Zombozo This Way Comes
- Animo Crackers
- The Plumber Headquarters is similar to the "Prison 42" from the TV show The Avengers: Earth's Mightiest Heroes.