Plumbers

The Plumbers are a secret organization that have many high tech gadgets and protect Earth from various alien & paranormal threats. They were said to have disbanded shortly after Vilgax was defeated by Max Tennyson.

Ben 10
In the original series, the Plumbers are a secret government organization that protects the general public from any alien threat. Their main advesary was the alien warlord Vilgax, Max Tennyson (AKA Grandpa Max) was a member in his youth and was ultimately the one who defeated Vilgax. Most of the organization itself has disband, however a few of its members (like Max Tennyson & his relatives) remain in a semi-active capacity.

Max Tennyson is effectively forced out of retirement after Ben obtains the Omnitrix. Grandpa Max uses his experience as a Plumber (along with various Plumber gear & weapons) to aid his grandson against various foes, including his old enemy Vilgax.

In "Big Fat Alien Wedding", it is revealed that the Plumbers have been generations-long feud with alien race known as Sludge Puppies (or The Sludges). However, when a close-relationship was formed between Plumber Joel Tennyson (Max Tennyson's nephew) & female Sludge named Camille. A truce was forged as a result of their relationship, and their wedding was to be the first ever marriage between a mud alien & a human, and was meant to put an end to years of fighting. The bride's parents & ex-boyfriend (all Sludges) tried to stop the wedding, however they were defeated by the combined efforts of Camille & Tennyson's, and thus the two were married. Though Joel's parents (both of whom were Plumbers) were against the marriage at first, they later realize how unfairly they had treated Camille and finally accepted her as their daughter-in-law, thus putting an end to feud.

The Plumber's main base is located inside of Mt. Rushmore, where both the Null Void projector & the Sub-Energy are stored. In "Truth", the Null Void projector was stolen by Phil (Max Tennyson's former partner) as part of scam to profit off catching aliens he himself released, however his plan was thwarted by Max & Ben Tennyson. There also a base located within Fort Knox.

Both bases were later attacked by Driscoll the Forever King (an Ex-Plumber who join the Forever Knights) with the help of the Negative 10.

Ben 10: Race Against Time
An group of active Plumbers based Bellwood is introduced in the movie Race Against Time. They have a secret underground base where the "Hands of Armageddon" were kept. Ben Tennyson and Gwen Tennyson only came to the Bellwood base once. The groups main objective was to protect the Hands of Armageddon from Eon, which eventually entailed protecting Ben Tennyson from Eon (who wished to use the Omnitrix to transform Ben into a younger version of Eon, in order to use the Hands of Armageddon). It is likely they disbanded after Eon was defeated.

Ben 10: Alien Force
In this series, the Plumbers are revealed to an inter-planetary peace-keeping force, with both human & alien members. In "Darkstar Rising", it is revealed that all Plumber active on earth was officially ended after Vilgax final defeat at the hands of Ben Tennyson. However Max Tennyson discovers that an alien race called the Highbreed & their minions the DNAliens, are up to no good and he warns his superior officer, Magister Labrid (a fish-like alien) there is trouble brewing on Earth. The Magister quickly discovers Max has gone missing and mistakeningly tries to capture Ben & Gwen (unaware that they are his Grandchildren) believeing they are responsible. Upon discovering who they are, he asks for their assistance in discovering the reason for Max disappearence. The three of them manage to interupt an arms deal between the Forever Knights & the DNAliens, with Ben's old-rival, Kevin Levin (AKA Kevin 11) as the middle-man (or go-between). After a brief battle, they captured Kevin and convinced him to help them find out what was going on (Kevin decided to help as he had not been paid). They tracked the weapons back to one of the Forever Knights castles. During a battle with the Forever Knights, Magister Labrid is fatally wounded. He dying wish was for them to finish their mission and charged them with protecting the Earth from this new threat.

In "Everybody Talks About the Weather", it is revealed that Plumbers poses special badges (which resembles the Omnitrix face plate). There is also a practice where alien Plumbers who have inter-breed with humans, give their hybrid-offspring a Plumbers' Badge to prevent them being misstakenly arrested by other Plumbers. They are generally refered to as Plumbers' Kids.

In "Darkstar Rising", Ben, Gwen, and Kevin are forbidden to fight against the Highbreed threat by Magister Prior Ghilhil of the Plumbers, who doubts the Highbreed are even as much of a threat as they claim. However, all three sides find themselves working together when Mike Morningstar, AKA Darkstar, captures all but Gwen to feed his powers. With the help of the DNAliens, Gwen frees her friends and Mike is captured while the Highbreed Lord and the DNAliens escape. In gratitude, Magister Ghilhil makes the team Honorary Plumbers so they can defend the Earth legally.

In Ben 10

 * Max Tennyson - (retired)
 * Joel Tennyson - (Max Tennyson's Nephew)
 * Betty Jean & Gordon Tennyson - (Joel's parents)
 * The Bellwood Plumbers
 * Pete Redbloom
 * Xylene - (possible member)

Rogue Plumbers

 * Phil - (Max Tennyson's Ex-Partner)
 * Driscoll - (A Plumber who was expelled for steal alien tech, later joined the Forever Knights and became the Forever King.)

Plumbers in Alien Force

 * Magister Labrid - (A fish-like alien and Magister of Planet Earth)
 * Magister Prior Ghilhil - (An alien with the rank of Magister Prior)

Honorary Plumbers

 * Ben Tennyson - (Was made an Honorary member at the end of "Darkstar Rising")
 * Gwen Tennyson - (Was made an Honorary member at the end of "Darkstar Rising")
 * Kevin Levin - (Was made an Honorary member at the end of "Darkstar Rising")

Former Alien Members

 * Alan Albright's father - (an unnamed Pyronite)
 * Kevin's biological father - (name & race unknown)
 * Mike Morningstar's biological father - (name & race unknown)

Plumbers' Kids
Are the Hybrid offspring of various alien members of the Plumbers.

List of Plumbers' Kids

 * Alan Albright - (A male African-American Human/Pyronite Hybrid)
 * Mike Morningstar/Darkstar
 * Cooper - (possible)
 * Kevin Levin (Was revealed to be the son of a Plumber in "Darkstar Rising")

The Plumbers' Helpers

 * Pierce - (A Part-human/Part-Porcupine Alien, Helen's brother)
 * Helen - (A female Kineceleran/Human Hybrid, Pierce's sister)
 * Manny - (A male Tetramand/Human Hybrid)