After the release of her previous album Enya (1987), she secured a recording contract with Warner following a chance meeting with chairman Rob Dickins, who had become a fan of her music.

After a period of negotiations, Dickins signed Enya, granting her wish for complete artistic freedom without interference from management or deadlines to have albums finished.

[12] After a demo version of the album was put down, Dickins requested to have it re-recorded digitally at a more professional studio as the analogue equipment at Aigle had created an abundance of tape hiss, causing the music to suffer.

[12] Recording took place at Orinoco Studios in Bermondsey, London and lasted for two months with Ross Cullum who carried out co-production, engineering, and mixing duties.

[12] Away from the "intimate and personal" setting of their home studio, Enya found working in London more difficult as the busy city caused many distractions.

Enya felt the need to have layers of vocals to add a "human element" to her music as solely using keyboards and digital sampling sounded, to her, "a bit linear and straight".

With Nicky as their manager, influenced by The Beach Boys and the "wall of sound" technique made famous by producer Phil Spector, the two often discussed the idea of layering Enya's voice to make it its own instrument.

[22] "Cursum Perficio" came about after Enya and the Ryans had seen a documentary on American actress and model Marilyn Monroe, who once wrote the phrase on the tiles on her front doorstep.

[12] Enya wanted her vocals to be "bold and up-front" like that of a choral piece, and realised early on that translating its lyrics into English or Irish would not complement the music, so Latin was used.

[12] They wanted the song to capture a feeling of unrest, to which Cullum suggested they bring in Hughes to play the rototoms and African hand drums.

[12] Its title refers to the same-titled book by English novelist Miss Read, whose depictions of country and village life, and the people who lived there, appealed to Enya.

[21] "Orinoco Flow" was the final track written for the album,[21] but it was one that Enya recalled was difficult to work on and which involved several breaks from recording before coming back to it several weeks after.

She later pointed out the absence of deadlines to complete the album, as granted in her contract with Warner, which allowed the song to be developed over a period of time until "we were able at the end to listen to it and say 'this is good'".

[29] It originated from a riff she had developed after Nicky suggested playing a melody in five octaves; they left the arrangement as it was, until they realised the album needed one more track.

[6] Nicky spoke about Enya's style of composing for song: "There are five synths midi'd but then she plays chords over these random arpeggiators with notes popping in and out where you don't expect them.

[29] Dickins realised its sleeve design was an important aspect in its marketing campaign to ensure the album's success as it was "not the kind of music that slots easily into Radio 1 ...

"[5] Enya was "very happy" with the cover, calling it "very classic" and "in taste with the music", not portraying her as the latest "girl on the scene" when compared to other female solo artists at the time, such as Madonna and Kylie Minogue.

[29] Dickins decided against the inclusion of a detailed set of liner notes and lyrics with their translations as it encouraged the listener to conjure up their own images and understanding when they play it, a decision that Enya supported.

[53] Enya embarked on a worldwide media tour which lasted from September 1988 to May 1989 and included press, radio and television interviews and appearances, record signings, and lip-sync performances of songs from Watermark.

In an April 1988 review, Hot Press reporter Liam Fay wrote the album is "A lifetime's worth of sights, sounds and experiences condescend into an orderly and lucid aural aquarium".

He praised her orchestral-like vocals on "Cursum Perficio", the instrumentation on "Storms in Africa", "The Longships", and "Exile", and the "exquisite liqueous pop" of "Orinoco Flow" which, as he predicted, "should be a hit single".

Fay also felt "Na Laetha Geal M'óige", "On Your Shore", and "Evening Falls..." sound "too hymn-like for their own good", and pale in comparison to the rest of the album and Ryan's production "reveals a different hue" each time one listens to it.

He described "Orinoco Flow" as "lushly romantic" and praised the production on "Evening Falls..." and "Miss Clare Remembers", which evoke a "cathedral ambience, with multitracked choirs and shimmering echo".

He compared her methods to English singer Claire Hamill but "much better", and praised her personal songs like "On Your Shore" to invite the listener to recall homes of their past, "a bittersweet journey".

He deemed "Na Laetha Geal M'oige" "one of the most beautiful melodies recorded by anyone recently" that is sung with such conviction, the Irish lyrics do not affect the music.

"[59] In a review printed in The Boston Globe, Steve Morse called the record a "series of lush dreamscapes that team the vocal beauty of Irish traditional song with multitracked synthesizer tones", and compared it to works from fellow ambient and new age artists Jean-Michel Jarre, Vangelis and Brian Eno.

[49] Helena Mulkerns in Rolling Stone called the album "a rich mood piece of broad proportions" and "a glorious aural mosaic".

The title track "sails the listener gently into an ebb-and-flow movement that permeates the album" that contains multi-vocals she described as "distinctive" and "striking".

"[56] In The Village Voice, Robert Christgau labelled the album a "must to avoid" and said Enya exploits popular music's "old reliable women-are-angels scam" while "humanizing technology, perpetrating banal verse in three languages (I'm guessing about the Gaelic after reading the English and figuring out the Latin), and mentioning Africa, the Orinoco, and other deep dark faraway places".

[63] In a retrospective review for AllMusic, critic Ned Raggett said the record "established her as the unexpected queen of gentle, Celtic-tinged new age music" with a subtlety that produced strong tracks as a result.