People forget that prior to the middle class boom when cheap land in the suburbs was opened up with the automobile, home ownership rates were much lower in the US and it was quite standard to supplement your income by hosting a boarder to live in your home. This was very common all throughout the 19th Century and well into the 20th.

There is a nice census article on this. Here's a sample quote:

"In a study of Boston neighborhoods circa 1880, 37 percent of boarders were between 20 and 29 years old, and 27.5 percent were between 30 and 39 years old (see also, Scopilliti and O’Connell 2008). Widows and single women commonly made up their ranks. Indeed, estimates from 1900 show that 38 percent of working single women lived away from their families as boarders, often in the homes of their employer (Goldin 1980)."

https://www.census.gov/content/dam/Census/library/working-pa...