Starring his then wife Shoba and Pratap, with N. Viswanathan, Gandhimathi, Mohan and Bhanu Chander in supporting roles, it is based on two novels: Idhuvum Oru Viduthalai Thaan (1978) by Rajendra Kumar, and The Collector (1963) by John Fowles.

The film received critical acclaim, with particular praise for the performances of Pratap and Shoba, and Ilaiyaraaja's music; the song "Yen Iniya Pon Nilavae" attained immense popularity.

It was a commercial success, running for over 200 days in theatres, and responsible for a resurgence of the thriller genre in Tamil cinema at that point.

Troubled by his constant anger, Chandru meets with a psychiatrist who advises him to marry soon so that he will no longer be lonely, saying the loneliness is leading him to dwell on his past and indulge in extreme acts.

Raghunath understands Chandru's love for his mother and his traumatic childhood, which had made him develop a hatred for women with loose morals.

[14] Pratap, who previously collaborated with Mahendra on Azhiyatha Kolangal,[15] was cast as Chandru, the mild-mannered and psychopathic serial killer of prostitutes.

[27] During the post-production phase, Anuraatha Rajkrishna was chosen to dub Shoba's voice; in preparation, she "spent days on an empty stomach" to get the right speaking style.

[28] In making Moodu Pani, Mahendra faced the challenge of distinguishing it from Bharathiraja's Sigappu Rojakkal (1978), which had a similar theme.

[29] Although Moodu Pani is officially based on Idhuvum Oru Viduthalai Thaan,[14] it is widely discussed as also having been inspired by Alfred Hitchcock's thriller Psycho (1960).

[13][30][31][32] R. Ilangovan of Frontline stated that while Mahendra was inspired by Psycho, his camera work, the "mist-covered nights" of Bangalore and Ooty, and the "weirdness" of the subject made the film "unique".

[14] According to Sify, there is a strong similarity between Moodu Pani and Psycho as the male leads in both films keep the skeletal remains of their respective mothers, which they continue to communicate with.

[33] Chellappa of Hindu Tamil Thisai compared Moodu Pani to Psycho and Sigappu Rojakkal as all three films depict their leads as committing murders to achieve peace of mind.

[37] In the 2017 book Indian Horror Cinema, Mithuraaj Dhusiya likened it to a slasher film because of the numerous prostitutes murdered by Chandru.

[38] K. Hariharan, director of the L. V. Prasad Film & TV Academy, noted that sexuality and the repression of desire were the dominant motifs in Moodu Pani, expressed through the mysterious misty atmospheres of Ooty where the protagonist confronts their psychological antagonist.

[25] He also noted that Moodu Pani, like many of Mahendra's films, borrowed its themes and stylistic devices from French New Wave and New Hollywood styles of filmmaking.

[26] Crime fiction writer Pattukkottai Prabakar considers Moodu Pani, along with Sigappu Rojakkal and Nooravathu Naal (1984), to explore the personalities and behavioural traits of psychopaths in detail.

[61] Soundara Kailasam of Kalki appreciated the film for various aspects, including Shoba's performance, Ilaiyaraaja's music, the fewer songs, and the cinematography.

I told him that this song was so beautiful, that it was a great wedding gift for him from Ilaiyaraaja.After Sigappu Rojakkal, there was a resurgence of the thriller genre in Tamil cinema, as evidenced by films like Moodu Pani.

[65] M. Suganth of The Times of India stated that Mahendra "changed the landscape of Tamil cinema with his distinctive visuals and eclectic films" such as Moodu Pani.

"[67] Pratap recalled in January 2015 that it was the simultaneous release of Moodu Pani and Varumayin Niram Sivappu that made him a star.

[55] However, both Varumayin Niram Sivappu (which depicted Pratap as an eccentric director obsessed with an actress) and Moodu Pani led to him being typecast in similar roles.

[17][68] In Iruvar Mattum (2006), Azhagu (Abhay) keeps the skeletal remains of his mother and frequently talks to her; Sify compared this plot detail to that of Moodu Pani and Psycho.

[70] Reviewing Amara Kaaviyam (2014), K. Siddharth of Sify praised its cinematographer Jeeva Shankar for "showcasing Ooty in trademark [Balu Mahendra's] way" in the style of Moodu Pani.