The “Swabian housewife” has traditionally been regarded as such a paragon of thrift in Germany that the former chancellor Angela Merkel once held her up as a model for the nation’s finances.

Folklore has it that mothers from this southwestern region used to test their sons’ prospective brides by asking them to pare the rind from a block of cheese: if she cut away too much, she was dismissed as wasteful; too little and she was thought slovenly.

Even by these standards, though, an unnamed 51-year-old woman from the small Swabian town of Spaichingen has pushed parsimony to a fresh extreme.

Police in the nearby city of Konstanz have opened a criminal investigation into the woman on suspicion of stealing €0.15 worth of rainwater from her neighbour in the early hours.

Aerial view of illuminated residential buildings at night.

The town in the southwest of Germany

SILAS STEIN/ALAMY

According to the local constabulary, at 4am on July 25 she crossed the street carrying two large watering cans and filled them from the neighbour’s water butt. She then allegedly made a second trip to the scene of the crime, hiding behind a rubbish bin in an apparent attempt to elude detection by a passing car.

The police force said that even though the value of the 40 litres of stolen water was negligible, it was the principle that mattered.

“Taking another person’s property fulfils the criteria for the offence of theft,” it said. “Once it is in the barrel, [the water] no longer belongs to the heavens, but to the [barrel’s] owner. The woman must now be held answerable for the theft of low-value items.”

Unlike in the UK, where there is significant public dissatisfaction at the police’s apparent neglect of shoplifting and other petty theft, such cases are often taken seriously in Germany.

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National police statistics show that roughly nine out of ten cases of shoplifting reported to the authorities are successfully investigated, although the figures for other kinds of theft, such as stealing bicycles or handbags, are much lower.

In theory, theft is punishable with a fine or a prison sentence of up to five years. In practice, thieves who steal items worth less than €50 frequently get away with a warning or an out-of-court settlement, especially if they are first-time offenders.

However, the state of Baden-Württemberg, to which Spaichingen belongs, pursues these cases with vigour. Several years ago it abolished the €25 threshold for prosecutions in an effort to “strengthen confidence in the functioning of the rule of law” and eliminate “carte blanche” for shoplifters and other minor thieves.

While some citizens have welcomed this zealous approach, others have complained that going after the alleged rainwater thief is unduly draconian and a waste of police and prosecutorial resources.