As she surveyed her home in Hong Kong, Liu Lanhua tried not to be bothered that her narrow kitchen doubled as the family’s only bathroom.

Colanders, pans and hairbrushes dangled above the toilet. Jars of chili oil were precariously balanced on water pipes. A stew of chicken wings and chestnuts warmed on an electric stove a few feet from the shower faucet.

She and her 12-year-old daughter are among 220,000 people in Hong Kong living in subdivided homes, which have long been among the starkest examples of the city’s vast income inequality.

Now her home is under threat. Hong Kong’s leader, John Lee, last month announced that the city would impose minimum standards on the size and fixtures of such apartments. The policy is expected to phase out more than 30,000 of the smallest subdivided homes.

In Ms. Liu’s home, there was no space for a sink; the only spot for two pet turtles was in a basin under the fridge. “If we had money, these would be in separate rooms,” she said, looking at the cluttered kitchen and toilet.

Beijing has urged the Hong Kong government to get rid of subdivided units and other tiny homes by 2049, because it regards the city’s housing shortage as one cause of the antigovernment unrest of 2019.