During the early 20th century, Martinez gained a colorful reputation for its unique fleet of floating brothels anchored in the middle of the river. Police raids were regularly made but timely warnings always allowed their clients to be absent. Fines for running houses of prostitution provided significant revenue to the county for many years and became a practical method of taxing the profits of these illegal enterprises. Rumors suggest that some of the best customers of these watery "entertainment" boats were the local politicians, lawyers and judges.
Their patronage may have provided protection for the illegal operations. Drinks were also sold allowing clients to socialize with the soiled Martinez mermaids before and after services rendered.
According to court records, Margaret Bantz and Millie Landt were some of the most notorious water loving madams on the river. During the 's the floating pleasure palaces found that local objections and difficulty with access forced their closing.
It was one of the first recorded instance of a county noise pollution problem. Open prostitution had been an accepted fact of life during the settling of Contra Costa County. Many county brothels masqueraded as "boarding houses" whose guests were exclusively young women.
Many had interesting names. Of course, a request for tea would have been greeted with astonishment. Women were always in short supply in this thinly settled, largely rural county. The early vaqueros, sheep headers and field hands led lonely lives without much opportunity to meet available women or, even more importantly, the financial ability to marry.
