The Economist heralded the book's publication, saying "If there is no place for Watership Down in children’s bookshops, then children’s literature is dead." Peter Prescott, senior book reviewer at Newsweek, gave the novel a glowing review: "Adams handles his suspenseful narrative more dextrously than most authors who claim to write adventure novels, but his true achievement lies in the consistent, comprehensible and altogether enchanting civilisation that he has created." Kathleen J. Rothen and Beverly Langston identified the work as one that "subtly speaks to a child", with "engaging characters and fast-paced action [that] make it readable." This echoed Nicholas Tucker's praise for the story's suspense in the New Statesman: "Adams ... has bravely and successfully resurrected the big picaresque adventure story, with moments of such tension that the helplessly involved reader finds himself checking whether things are going to work out all right on the next page before daring to finish the preceding one."
The "enchanting" world Prescott admired was not as well received upon its 1974 American publication. Although again the object of general approval, reception in the United States was more mixed, unlike the predominantly positive reviews of 1972. D. Keith Mano, a science fiction writer and conservative social commentator writing in the National Review, declared that the novel was "pleasant enough, but it has about the same intellectual firepower as Dumbo." He pilloried it further: "Watership Down is an adventure story, no more than that: rather a swashbuckling crude one to boot. There are virtuous rabbits and bad rabbits: if that’s allegory, Bonanza is an allegory."
John Rowe Townsend notes that the book quickly achieved such a high popularity despite the fact that it "came out at a high price and in an unattractive jacket from a publisher who had hardly been heard of." Fred Inglis, in his book The Promise of Happiness: Value and meaning in children's fiction, praises the author’s use of prose to express the strangeness of ordinary human inventions from the rabbits' perspective.
Watership Down's universal motifs of liberation and self-determination have led to the tendency of minority groups to read their own narrative into the novel, despite the author's assurance (in 2005) that it "was never intended to become some sort of allegory or parable." Rachel Kadish, reflecting on her own superimposition of the founding of Israel onto Watership Down, has remarked "Turns out plenty of other people have seen their histories in that book...some people see it as an allegory for struggles against the Cold War, fascism, extremism...a protest against materialism, against the corporate state. Watership Down can be Ireland after the famine, Rwanda after the massacres." Kadish has praised both the fantasy genre and Watership Down for its "motifs [that] hit home in every culture...all passersby are welcome to bring their own subplots and plug into the archetype."
Adams won the 1972 Carnegie Medal from the Library Association, recognising the year's best children's book by a British subject. He also won the annual Guardian Children's Fiction Prize, a similar award that authors may not win twice.[a] In 1977 California schoolchildren selected it for the inaugural California Young Reader Medal in the Young Adult category, which annually honours one book from the last four years. In The Big Read, a 2003 survey of the British public, it was voted the forty-second greatest book of all time.