The Waters of Mars (TV story)

The Waters of Mars was the 2009 Autumn Special of Doctor Who.

Mostly a character piece, it showed the extremes to which the Doctor would go when unregulated by either other Time Lords or companions, specifically by trying to change a fixed point in time. It continued the "He will knock four times" story arc begun in the previous episode.

It won a 2010 Hugo Award for writers Davies and Ford. After years of stability at the producer's office, The Waters of Mars was the fourth episode in a row to be produced by a different person.

Just prior to his regeneration a significant change in the Tenth Doctor's character was presented, showing a much darker and callous side. Up to this point he had viewed himself as a survivor of the Time War, but now he started to believe that he was the "Time Lord Victorious" and that the Laws of Time were his to command, allowing him to break them because there were no other Time Lords around to stop him. After saving Adelaide Brooke even though he knew her death was fixed, he realised that he had gone too far and that he should not influence history and the future on such a large scale.

Adelaide's flashback also indicates that the Daleks are aware of people and events important to the universe's history. The consequences of altering such important events was displayed in The Wedding of River Song, when the Silence create an event that appears to be the Eleventh Doctor's assassination; if the event is prevented, it will stop time and cause all of history to happen at once at the epicentre. In time, the effects will spread to the rest of reality and the universe would simply collapse.

This is the first time since 1980's Logopolis, that the Cloister Bells have rung to signal to the Doctor that he will regenerate soon. However, unlike the previous time, where the Fourth Doctor was willing to wait for his time to come, the Tenth Doctor was greatly fearful of having to regenerate. Unknown to the audience at this time, the Doctor had only one regeneration left; he had aborted one in Journey's End, and kept one secretly buried in his memory.

While The End of Time is the next aired episode featuring the Tenth Doctor, the events of The Day of the Doctor follow The Waters of Mars in the Tenth Doctor's timeline.

The episode would later be retroactively incorporated as a part of the multi-medium Time Lord Victorious storyline, with the officially promoted exploration paths placing it somewhere after Defender of the Daleks from the Tenth Doctor's perspective.

Synopsis
Mars, 2059, Bowie Base One. Last recorded message: "Don't drink the water. Don't even touch it. Not one drop."

Plot
The TARDIS arrives on Mars and the Tenth Doctor steps out in his spacesuit from Sanctuary Base 6, seemingly just to relax and enjoy the landscape. Stumbling across a base inhabited by a team from Earth, he is detained by a remote-controlled robot called "Gadget" and taken inside.

The base commander, Adelaide Brooke, holds the Doctor at gunpoint, demanding to know his name, rank and intentions; he responds "the Doctor; doctor; fun." The crew wonder if he's from a rival space agency, to which the Doctor decides to agree to; he then asks who they are. Adelaide scoffs at him saying that everyone on Earth should know who they are as they are the first colonists on Mars.

The Doctor realises that the date is 21 November 2059, and this is Bowie Base One. History has it that on this date, the base was destroyed in a mysterious explosion and Brooke and her crew were all killed as a result. Unwilling to break the laws of time and interfere with a "fixed point" in history, the Doctor states that he is sorry with all his hearts, but he needs to leave.

However, a crisis is developing: a crew member, Andy Stone, has been infected by a mysterious life form which takes over his body and causes him to gush copious amounts of water. Maggie Cain, another crew member, screams as Andy growls and attacks her, leaving her unconscious in the biodome corridor. After second-in-command, Ed Gold, attempts to establish contact with Andy and Maggie over the comlink and they hear Andy's guttural snarls over the comlink, Adelaide confiscates the Doctor's spacesuit, thinking he may be responsible for the infection in some way, and orders him to come with her and physician, Tarak Ital, MD, to investigate.

As the Doctor, Adelaide and Tarak walk down the corridor with Gadget, operated by Junior Technician Roman Groom from the central dome, the Doctor finds it annoying that the robot repeats its name. The Doctor asks the famous Adelaide Brooke if the Bowie Base One mission was worth everything she sacrificed, to which the Captain replied that Earth was reaching the point of uninhabitability with all the smog and pollution, all of which pushed humanity to the brink of extinction, and that to walk on another planet without any smoke but just infinite sky... yes, it's worth it. The Doctor is greatly impressed and tells Adelaide that she was the woman with starlight in her soul. Adelaide says nothing, but her expression is thoughtful.

As they walk down the corridor, Adelaide's torch picks out Maggie's unconscious form, and they race to her. She is still alive and breathing, but has a nasty gash on her head. Tarak calls Nurse Yuri Kerenski over the comlink, who arrives with a medi-pack for Maggie and a stretcher. Ed also arrives, after realising that only one other person was in the biodome — officer Andrew Stone. Ed tells Maggie that the only way this couldn't have been an accident was that Andy has gone berserk. Adelaide dismisses him using rank and citing security protocol.

Meanwhile, Senior Technician Steffi Ehrlich checks the growling noise on the diagnostics unit of the computer, and is shocked to discover that the growling was the voice of Andy Stone. She calls Adelaide on the comlink to warn her that it seems Andy has gone wild. Adelaide, Tarak and the Doctor step into the dormant biodome, and, using his sonic screwdriver, the Doctor restores the lights, all of which had been shorted out by the infected Andy. Tarak goes to the left to check the biodome airlock doors, while Adelaide and the Doctor go to the right. Maggie awakens as they walk down the biodome, unwittingly carrying the mysterious virus which is hiding in her body, but she has amnesia of the previous occurrences. Slightly groggy, she tries to get Yuri to open the door for her to come out, but Yuri refuses, saying a little rest won't hurt. As he turns his back, however, Maggie's features crease into a disapproving frown, indicating that she is not herself anymore...

Tarak is the first to find Andy, who swings around onto him and infects him with the virus by pouring water over his head, causing Tarak to acquire the same zombie-like characteristics that Andy has. At that point, in a conversation with Yuri, Maggie's virus finally becomes active. The organism occupying her body reveals its desire to reach Earth, a planet rich in water. Yuri is first alerted to her transformation when she speaks in a deep voice distorted by the internal fission, "We should like that world", while gazing at planet Earth on a monitor, and Yuri, stammering in horror, briefly describes what has happened to their comrade: the skin around her mouth has become horrifically cracked and broken, her teeth have blackened and she is emitting water in an overwhelming torrent from her mouth, as if she is drowning.

Adelaide, realising the biodome is unsafe, tries and fails to establish contact with Tarak over the comlink, and then she and the Doctor run back through the dome in time to see Tarak transform. While Adelaide points her gun at her infected crew member, the Doctor tries to encourage Andy to take his dripping hand away from Tarak's head. Amazingly, Andy seems to obey and yanks his hand away from Tarak, who collapses as his mutation is completed. The Doctor then acts friendly and introduces himself to the infected man, but then Tarak flicks his head up and turns to face them, and they are horrified to see that Tarak now looks just like Andy — the skin of his mouth has cracked, his eyes are a dead, white-blue, his teeth have gone black and copious water pours from his mouth. The Doctor, realising they have to get away, runs with Adelaide hot on his heels, but then Andy and Tarak run after them back through the dome to the door, whose seals are set at maximum, just as Andy fires a thick stream of viral water from his hand onto the door. Not a single drop gets inside, but Andy then steps closer to the door and slams himself against it.

Ed reaches the medical dome to see Maggie for himself. He is shocked by her appearance, and his face shows his fear. Steffi, geologist Mia Bennett and Roman look through the medical dome camera at Maggie, and Steffi wonders what she has become. She calls Adelaide over the comlink, begging her to come back, but Adelaide orders Ed to make sure that Maggie is contained. Ed confirms it, then Adelaide orders all the water supplies to be closed down, and also orders the others: "Don't drink the water, don't even touch it, not one drop". The Doctor examines Andy, who looks at him with his dead white eyes and suddenly grins. The Doctor fails to get a response from the zombie or his friend standing behind him. Andy then starts examining the door, and the Doctor realises that humans are 60% water, so they are the perfect host for something like a mutating water virus. The Doctor says he has to go, and that he can't stay to see what happens, leaving Adelaide confused.

Suddenly, Andy slams his whole body against the door, making both the Doctor and Adelaide jump. Andy growls at Tarak, who then attacks the door by firing water from his mouth into the side, fusing the systems and causing the tortured door to open. The Doctor and Adelaide escape and start running down the corridor back to the central dome, but Andy and Tarak then break out of the biodome doors and race after them. Realising that the infected men can run faster than them, the Doctor sonics Gadget, making him able to move considerably faster, and he and Adelaide hitch a ride on the robot, which causes agony to Roman Groom, the robot's operator. The Doctor notes the crew should have had collapsible bikes brought along.

Andy and Tarak, still infected, chase the Doctor, Adelaide and Gadget back to the central dome, but are unable to pursue them any further due to the Hardinger seals in the central dome airlocks and are contained in the base's "bio-sphere" section while Maggie is secured in the medical wing. The Doctor, however, is worried about the doors and whether they can protect them from creatures with such power, making a chilling statement, "Water is patient, Adelaide, water just waits. It wears down the clifftops, the mountains, the whole of the world. Water always wins!"

In the medical dome, the Doctor and Adelaide meet the infected Maggie, who just stares at them all, but she suddenly takes an interest in the Doctor when he speaks ancient North Martian to her, Maggie appearing to understand it. The Doctor realises that, looking at Maggie's blackened mouth and cracked skin, that whatever the infection is, it doesn't just live as water, it can produce immense amounts of it. The crew plan to evacuate in an escape shuttle, and the Doctor grimly tells the news to Adelaide that they could be carrying the infection, as they discovered, from Maggie's transformation, that the infection could hide in a human and mutate it at any moment. Adelaide goes to inspect the ice field to validate the Doctor's suspicions, offering him his suit back to him and allowing him to leave. Contemplating leaving, the Doctor stands still for a few seconds before racing off after her.

Yuri evacuates the Medical Dome and heads for the Central. After he leaves, Maggie breaks out of confinement by seeping water into the door and alerts Andy and Tarak in the biodome corridor to the humans' plans by emitting a terrifying alien scream that is heard by the two men over a hundred metres away. The infected men slowly lower their heads and then look towards the medical dome from which the scream is coming from, then they slowly walk away.

In the dome containing the glacier, the Doctor hypothesises that the virus may have been preserved and imprisoned in the glacier by the Ice Warriors to prevent its spread. However, before they can get to work, Adelaide queries the Doctor on how he knows so much about them. Reluctantly, the Doctor comments that she may have a story to tell, and Adelaide agrees. She says that when she was 10 years old, the sky had changed, as it was the moment when the Earth was snatched by the Daleks, and Adelaide says that she saw a Dalek float down to her window, and it saw her and just stared at her, then flew away.

Adelaide says that she knew, someday, she would follow it into the stars. The Doctor tells Adelaide that by doing so, she has created history and reveals some information; Adelaide's infant granddaughter Susie Fontana Brooke will grow up and, inspired by her grandmother, become the pilot of Earth's first lightspeed ship. This will pave the way for generations of her descendants to explore the galaxy, with one even falling in love with an alien prince and creating a whole new species. Adelaide, amazed at what a lasting legacy her and her family will have on the galaxy, asks the Doctor why he's telling her all this. The Doctor sadly replies that he's telling her as a consolation.

The Doctor and Adelaide work out, through the last message that Andy had recorded, that the water was fine to drink until the filter broke and the virus could get into the water supplies. Since the water won't yet have been drunk by the rest of the crew, they are free to leave. The crew plan to evacuate in an escape shuttle and the Doctor breaks the news to Adelaide that she must die today, on Mars, if events are to unfold as they should. Adelaide begs him to help but the Doctor insists he cannot interfere as her death is a fixed point in time, something even the Dalek knew which is why it didn't kill her as a child. Adelaide allows him to leave, saying two last words: "Damn you".

However, as the crew prepare to leave, Andy and Tarak climb the maintenance shafts in the main dome, walk to the centre of the roof of the control centre, fall to their knees and exude more water from their hands and mouths through the girders in the roof. The water quickly pours into the room and claims a distraught Steffi Ehrlich as she watches a tape left by her two daughters. Shortly afterwards, Roman is infected when a single drop of viral water falls on his cheek. However, he warns the others to run just before he changes. Mia screams and sobs as he is infected, but Yuri restrains her, and so they all make for the shuttle.

As Ed prepares the shuttle for take-off, Maggie infiltrates the shuttle and blasts water up the shaft into the pilot room, which cascades over Ed's arm, infecting him with the virus. However, just as the infection consumes him, and his eyes turn white-blue, Ed bids Adelaide, Yuri and Mia a final farewell, "See you later", and triggers the shuttle's self-destruct system, which traps the Flood on Mars but leaves the rest of the crew stranded with no means of escape. The Doctor narrowly avoids being caught in the blast but nevertheless can hear the cries of the doomed and their desperation as escape seems hopeless. Tortured by their suffering, he thinks about how the Time Lords used to enforce the laws of time, but they are all dead and gone now. He is the last Time Lord; he can make his own rules. With fierce determination on his face, he returns to the base to save the crew.

Finding the base falling apart, the Doctor rallies Adelaide, Mia and Yuri, and tries to assess the situation. Adelaide insists that the Flood cannot be stopped and the Doctor should save himself, but the Doctor tells of the prophecy that four knocks precede his death and states, "It doesn't mean right here, right now, 'cause I don't hear anyone knocking, do you?!". In response, the infected Andy slams his fist against the door three times; the Doctor shouts back, "Three knocks is all you're getting!" and electrifies the door, causing Andy to conduct the electricity, scream with pain, and let go of the door. The Doctor realises that coming from Mars, the Flood creatures would be very sensitive to heat. He reasons that if heat worked against the Ice Warriors, it would work against the Flood. He plans to activate the environmental controls and boil them. Adelaide reminds him of his assertion that they must die to ensure history unfolds correctly, but the Doctor replies that as the last of the Time Lords, "The laws of time are mine, and they will obey me!"

Suddenly, an explosion rocks the base, destroying its environmental controls. The Doctor states he will reactivate them from outside, only to find his spacesuit damaged as the glass in the helmet has cracked. Refusing to admit defeat, he plans to get a spacesuit from the storage section of Bowie Base, only to find the entire section flooded. At the same time, Maggie heads to the glacier and lets out a deafening shriek that begins to crack the very ice. As the glacier cracks under Maggie's screams, the base's stability begins to collapse; sensing that history will follow its inevitable course, Adelaide activates Action 5 — a nuclear device placed at the heart of the base. It will destroy the Flood, but also kill everyone else, infected or not.

The Doctor, realising they have one chance, uses Gadget to roll across the Mars landscape and bring the TARDIS to the base. As time runs out, Maggie continues to wail at the glacier, causing even more ice to crack, and the other infected personnel, Andy, Tarak, Roman and Steffi begin to scream as well, adding their efforts to the Flood's release. Just as the Flood begins to escape the glacier, the TARDIS materialises in the control room, and the survivors get inside. The nuclear device explodes, destroying the base and wiping out all the Flood creatures, the explosion unnoticeable from Mars' atmosphere.

The TARDIS materialises outside Adelaide's house on Earth. The Doctor exits followed by Adelaide, Mia and Yuri who can't believe that they're back on Earth. Gadget also exits, but immediately shuts down as he loses his control signal. Mia and Yuri are shocked by their experiences on Mars and by the Doctor's power, with Mia running away in fear. Yuri promises to take care of her and also departs. Adelaide asks what happens now in regards to her granddaughter's future, and the Doctor tells Adelaide that she can still inspire Susie but now can do it face-to-face. Some of the details will be different, but history will still follow its proper course. Adelaide, beginning to realise the full implications of her survival and how it could change her granddaughter's future and that of the whole human race, warns the Doctor that he has no way of knowing that and tells him she should have been left on Mars.

The Doctor argues that the rules of the Time Lords were only valid while their civilisation existed and that since he is the last of his race he has total authority over time. He states that he no longer considers himself to have survived the Time War, but to have won it and proudly declares himself the "Time Lord Victorious" and remarks that with this power he will now be able to save influential figures such as Adelaide as well as "little people": the likes of Yuri and Mia. Horrified and disgusted by the Doctor's newfound arrogance, Adelaide declares: "I don't care who you are, the Time Lord Victorious is wrong!".

After that, an adamant Adelaide returns home. The Doctor begins to walk away from her door, thinking all is well. He is grievously wrong. The windows of her house erupt with blue light as a single laser blast rings out. Adelaide has committed suicide, reverting the changes that the Doctor has made to the timeline. The Doctor feels the course of history being re-written. The people of Earth are made aware of the horrific events that occurred on Bowie Base One when Yuri and Mia eventually come forward. Captain Adelaide Brooke is now recorded as having died on Earth, with the circumstances of her suicide never found; however, Adelaide's granddaughter will still travel into space and pave the way for her future generations, inspired by Mia and Yuri's stories of her grandmother's heroism.

Only now understanding the full impact of his actions, the Doctor is overcome with horror and realises that there will be a price to pay for his interference. A vision of Ood Sigma appears in the street, prompting the Doctor to ask him whether he has finally gone too far — whether the time has come for him to die. The fear in his voice is incredibly potent. Unresponsive, Sigma vanishes, and the Doctor staggers back into the TARDIS.

The Doctor is greeted by the ominous sound of the Cloister Bell warning the Doctor that the time for him to regenerate is near. Solemnly tossing off his coat, the Doctor contemplates this. With a defiant "No!", he begins to work the machine's controls in a desperate plight to delay his impending death as long as he possibly can.

Cast

 * The Doctor - David Tennant
 * Adelaide Brooke - Lindsay Duncan
 * Ed Gold - Peter O'Brien
 * Yuri Kerenski - Aleksandar Mikic
 * Mia Bennett - Gemma Chan
 * Maggie Cain - Sharon Duncan-Brewster
 * Tarak Ital - Chook Sibtain
 * Andy Stone - Alan Ruscoe
 * Steffi Ehrlich - Cosima Shaw
 * Roman Groom - Michael Goldsmith
 * Emily - Lily Bevan
 * Mikhail - Max Bollinger
 * Adelaide's father - Charlie De'Ath
 * Young Adelaide - Rachel Fewell
 * Ulrika Ehrlich - Anouska Strahnz
 * Lisette Ehrlich - Zofia Strahnz
 * Ood Sigma - Paul Kasey

Individuals

 * Adelaide was 10 years old when the Earth was stolen by the Daleks, and she witnessed one herself.
 * Susie Fontana Brooke entered the Space Agency at an early age.
 * Tarak Ital attended Aga Khan University.
 * Steffi Ehrlich trained in Bundeswehr.
 * Margaret served on Project Midas.
 * Adelaide led Project Pitt Stop.

Earth history

 * Adelaide Brooke says that the last forty years on Earth have been chaos, with massive climate change, ozone degradation, and "the oil apocalypse"; humanity "almost reached extinction" during this period. Andy's obituary mentions "appalling storm conditions" in 2040, and climate change affecting agriculture in 2045.
 * Maggie believes the Doctor may be a Filipino or Spanish astronaut, as the Philippines are rumoured to be building a Mars rocket and Spain have a "space link" that they managed to keep secret. Andy Stone's sister worked for the Spanish space programme. Ed Gold believes the Doctor is from a non-state independent group, referring to the "Branson Inheritance", likely a reference to Richard Branson, a British industrialist who uses his vast wealth to fund commercial space flight.
 * Various lunar missions have been carried out, including ten German missions and Project Pit Stop, establishing a refuelling station on the moon. Mars was landed on in 2041, with Adelaide Brooke as part of the crew. Thirty years after 2059, Brooke's granddaughter Susan will pilot the first lightspeed ship.
 * At least one of the webpages (the one showing Brooke's granddaughter) dates from the 2080s or later, suggesting the Internet still exists in some form in the late 21st century.
 * On Adelaide's web page, there is a line of text at the top that states the page was updated on Thursday, 22 November 2059.
 * In 2059, flares emanating from the Sun are preventing clear communications between Earth and Mars.
 * One of the web pages indicates that the name of the spacecraft that brought Brooke's crew to Mars, and that of the vessel Ed Gold is forced to destroy, is Apollo 34.
 * NASA sent the space probe Phoenix to Mars, where it discovered liquid water.

Locations

 * Bowie Base One is Earth's first off-world colony.
 * Section F storages weather spikes, robots and atom clamps.
 * Bowie Base One is located on Mars in the Gusev Crater.
 * The Republic of Dagestan exists by the Caspian Sea, apparently a reference to the part of Russian Federation.
 * The Celestial Belt of the Winter Queen, the Dragon Star and the Map of the Water Snake Wormholes are all locations that will be discovered by Adelaide's descendants.

Species

 * The Doctor mentions the Ice Warriors and suggests that they may have frozen the Flood.

Robots

 * The Doctor said that he hates "funny robots" but notes that he'd be okay with a robot dog.
 * Gadget was built by Roman Groom using parts from the drones that constructed Bowie Base One.

TARDIS

 * Whilst on Earth, the Cloister Bell is audible while the Doctor stands alone in the TARDIS.

Story notes

 * This story was initially envisaged as a Christmas special. Several festive references remain, such as the crew on Mars preparing for Christmas dinner, and the snowing when the Doctor arrives back on Earth as he exclaims how he likes snow. In this phase of development, the episode had the working title of Red Christmas.
 * Lindsay Duncan became the oldest actress, and briefly the oldest individual, to be cast in the companion role (although like several before her, her official status as a companion will remain debatable). As Bernard Cribbins took on the companion role in TV: The End of Time, he became the oldest male actor and oldest individual in this role.
 * The episode ends with a dedication to Barry Letts. The former Doctor Who producer and writer had died several weeks before the broadcast.
 * Phil Ford's original draft was called A Midwinter's Tale, and was a sword and sorcery tale about an alien princess coming to Earth to be married. It ended with a long chase sequence in secret tunnels beneath Buckingham Palace.
 * When initially sketching out the story, Russell T Davies considered as a potential actress to play the character that eventually became Adelaide. In an early draft, the character that became Adelaide was Russian, but this was changed when, still thinking of Mirren as a potential guest star, Davies felt it would have been too close to the character played by Mirren in the film 2010: The Year We Make Contact. (REF: Doctor Who: The Writer's Tale - The Final Chapter)
 * In a deleted scene, the Doctor suggested that the Ice Warriors were unable to fully defeat the Flood and fled the planet as a result, explaining their absence.
 * This story won the 2010 Hugo Award in the category of Best Dramatic Presentation, Short Form.
 * The Waters of Mars is the last Doctor Who story released on DVD to include a "Next Time..." trail for a following episode, and one of only two Blu-ray releases, along with TV: Planet of the Dead, to include a "Next Time..." trail. The End of Time did not include such trailers even at broadcast, and while most episodes from series 5 were broadcast with a "Next Time..." trail, they were excised from the DVD and Blu-ray release.
 * "Bowie Base One" has a layout similar to the Moonbase from Gerry Anderson's TV series UFO.
 * "What the hell is that noise?" The sound is a proximity alarm, used in the movie 2001, a Space Odyssey.
 * "Bowie Base One" is a reference to David Bowie's song "Life on Mars". Another reference was made to one of Bowie's songs when Adelaide said the Doctor would be the last new human they would see in five years, a reference to "Five Years".
 * Chronologically, this was the last live-action story to feature David Tennant dressed in the Tenth Doctor's blue suit. TV: Dreamland would be the last of the Tenth Doctor's broadcast stories to depict him in the blue suit. He would appear in his more commonly worn brown suit for his final serial.
 * This story was intended to be transmitted on 21 November 2009, exactly 50 years before the events of this story, but had to be moved back. As such it was the only episode of the modern run of the series that is not a Christmas special transmitted on a Sunday until the broadcast of TV: The Woman Who Fell to Earth in 2018.
 * The original draft of this script had Adelaide surviving, with the Doctor realising upon seeing Ood Sigma, who arrived straight after he'd declared himself the "Time Lord Victorious", that he had gone too far. Russell T Davies later decided that Adelaide would need to commit suicide in order to stop the Doctor from going down a destructive path, a decision Julie Gardner agreed with. (REF: Doctor Who: The Writer's Tale - The Final Chapter)
 * Concerning the discovery of liquid water detailed in this story, on 28 September 2015, NASA made an announcement that there was proof of liquid water actually flowing on Mars.
 * This story is the only one of the David Tennant specials, to feature the normal end credits music, with the rest using the same music from the opening credits.
 * This is the fifteenth, and as of 2021, the most recent Doctor Who story to be directed by Graeme Harper.
 * Andy Stone's namesake was a Venusian character in Terry Nation's The Dalek Book.
 * Phil Ford envisaged Mars in the adventure as a terraformed planet, with the Bowie base personnel flying great distances to various installations. Russell T Davies encouraged him to take a much more low-tech approach to the story, with Bowie Base as the rugged first outpost on the untamed Martian frontier.
 * The service robot was inspired by WALL·E. The original plan was for the robot would initially be clunky yet lovable, but might later go mad and become a threat to the Doctor. This aspect of the character ultimately went unused.
 * Russell T Davies originally had an idea in which the Earth is frozen in time due to an alien presence. Much of the action would be based around a hotel, which would suddenly be empty except for one human who would become the Doctor's temporary companion. Originally, Davies had envisaged this as a father who would be driven to assist the Doctor by his desire to be reunited with his missing family. However, he was eager that one of the surrogate companions be a strong older woman - who might be played by an actress of the calibre of Judi Dench or Helen Mirren - and so this character instead became a grandmother.
 * Yuri's relationship with Mia is mostly removed in the final draft, except for a single moment when they hold hands.

Ratings

 * 15th November 2009 - 10.32 million (UK final)
 * 33.9% of TV share

Filming locations

 * Victoria Place, Newport
 * National Botanic Gardens of Wales, Carmarthenshire
 * Taff's Well Quarry, Cardiff, Wales

Production errors

 * The first of the web pages brought up in the episode claims that Adelaide had a seven-strong crew with her, though there were 9 people on-site not counting the Doctor.
 * In Yuri Kerenski's profile near the beginning of the episode, Tarak Ital's name is incorrectly spelt as "Tarek". Secondly, by pausing the image of his profile, it becomes apparent that the first paragraph is repeated at the bottom simply to fill what would be white space, in hopes it went unnoticed in general broadcast.
 * Steffi Erlich's profile lacks a full stop between two sentences, causing it to read "After finishing secondary school there and two years in the Bundeswehr, she studied physics at the RWTH Aachen University In 2042, she was awarded a diploma..."
 * Mia's obituary stated that she was born in America, however Gemma Chan portrays her with an English accent.
 * When it is revealed that Maggie is one of the creatures, the outer shot shows her hair back while in the closer shot, it is around her face.
 * When the Doctor opens Adelaide's door, the door unlocks and is opened till it is ajar. When Adelaide approaches the door, however, it is closed over.
 * While Yuri is watching a video of his brother, during the close up of Yuri, in the background, Maggie's mouth seems to be grey and cracked the same as the Flood. When the scene returns to a shot of Maggie, her mouth is normal. This is repeated twice until it shows Maggie throwing her head back.
 * When Susie Fontana Brooke's website is brought up, it shows her crew as identical as that of Bowie Base One. This is likely a typographical error, saying "Brooke's team consists of" when it should have read "Brooke's team consisted of", meaning the article referred to Adelaide's team, not Susan's.
 * One of the web pages shown said that the Dalek invasion (TV: The Stolen Earth / Journey's End) happened in 2008, but it actually happened in 2009. Adelaide's age is given as ten when it happened, which would still place it in 2009, as her date of birth is shown as 12 May 1999.
 * This continuity issue links back to the first series of the BBC Wales-produced Doctor Who, when the Ninth Doctor accidentally took Rose Tyler twelve months into the future in Aliens of London, causing what would be considered the present at the time to shift from 2005 to 2006. From that episode onward, every story featured in the Doctor Who universe set during the present was technically placed one year ahead of that in the real world at the time of broadcast, but not always explicit on-screen, causing confusion among writers and viewers. This lasted until The End of Time when the present perspective re-aligned with the current year of the real world.
 * The landscape that the TARDIS lands on at the beginning of the episode looks nothing like the CGI landscape which Gadget races across to bring it back to the base.

Continuity

 * The Doctor refers to his visit to Pompeii in August 79 in the company of Donna Noble. (TV: The Fires of Pompeii)
 * Adelaide recalls seeing a Dalek during her childhood, which occurred when Earth was relocated to the Medusa Cascade. (TV: The Stolen Earth / Journey's End)
 * The Doctor wears the spacesuit he picked up on Krop Tor. (TV: The Impossible Planet / The Satan Pit, Hide, Kill the Moon)
 * Carmen's prophecy, "He will knock four times", is mentioned. (TV: Planet of the Dead)
 * The Doctor reflects on his own relatively recent statements about the Time Lords and the Time War. (TV: Rise of the Cybermen, Doomsday, Gridlock, Utopia, The Sound of Drums, Last of the Time Lords)
 * The Doctor references a race known as the Ice Warriors that had lived on Mars. (TV: The Ice Warriors)
 * The Doctor says that he once fought against the Ice Warriors. (TV: The Seeds of Death, The Monster of Peladon)
 * The Doctor previously used the tactic of electrifying bulkhead doors. (TV: The Ark in Space)
 * Adelaide mentions the oil apocalypse that hit Earth during her lifetime. (TV: The Infinite Quest)
 * After the Doctor sees Ood Sigma (TV: Planet of the Ood) and enters the TARDIS, the Cloister Bell sounds. (TV: Logopolis, et al.)
 * The Doctor realises that his "summons" by Ood Sigma precedes what could be his death. He delays, beginning a series of travels before encountering him again. (TV: Dreamland, The Day of the Doctor, The End of Time)
 * The Eighth Doctor once changed a fixed point in time by saving Charlotte Pollard's life. She was supposed to die in the crash of the British airship R101 on 5 October 1930, (AUDIO: Storm Warning) an action which almost resulted in significantly catastrophic consequences. (AUDIO: Neverland, Zagreus)
 * Susie Fontana Brooke is mentioned to have entered the Space Agency. (PROSE: Fireball Surrenders!)
 * An alternate version of the Tenth Doctor would dub himself the Time Lord Victorious and rule over the universe as a tyrant, until a Raxacoricofallapatorian killed him. (COMIC: Four Doctors)
 * The Doctor, also unsuccessfully, previously attempted to avert established history in order to prevent the creation of the Eminence. (AUDIO: The Reviled, Masterplan, Rule of the Eminence)

International broadcasts

 * - New Zealand: 29 November 2009
 * ABC1 - Australia: 6 December 2009
 * BBC America: 19 December 2009
 * Space - Canada: 19 December 2009 ; rebroadcasts on 20 December 2009 and 2 January 2010.
 * Virtually no major edits were made to The Waters on Mars for any of its broadcasts on Space on 19 and 20 December, except that the preview for The End of Time was omitted (the dedication to Barry Letts, however, remained intact).
 * France - 30 October 2010

Home video releases
The four specials along with The Next Doctor were released in North America on both DVD and Blu-ray in a box set on 2 February 2010. This DVD would then be released in the UK in 2014, with the same content intact.

The Waters of Mars was released with The End of Time in a 'Winter Specials' DVD and Blu-Ray Box Set.