Miss Emily Pride, an old teacher of Alleyn's, inherits the place from her sister and comes to inspect her new property with plans to stop what she considers to be the vulgar exploitation of gullible and desperate people.

Julian Symons wrote in The Sunday Times that the industry that springs up around the waterfall (including the festival) "gives Miss Marsh the chance to use her gift for gentle social comedy, but a decline sets in with the murder and a rather humdrum investigation.

"[2] Violet Grant in The Daily Telegraph shared Symons's opinion of the book's strong points: "There is some fun at the rather obvious expense of the local Festival, but it is not, on the whole, one of Miss Marsh’s best.

"[3] Francis Iles reviewed for The Guardian, saying that the book's subject "admirably suits this lively writer: fraud combined with near mysticism based on a miracle-working fountain, with the bonus of a nicely puzzling little murder.

"[4] The Illustrated London News thought it a return to form, "Not that Dead Water is a patch on her earlier books featuring Handsome Alleyn: still, this story of murder in the 'healing' pool of a Cornish parody of Lourdes embodies a good mystery, and one of those tough, splendid old women in which Miss Marsh specialises with such skill.