The "family" in Rome included more than just the basic family of father, mother, and children. It also included all the people who were part of the household such as the slaves and servants. As a result, some families in Rome grew quite large. The emperor's family often included thousands of members.
The Romans built aqueducts to carry fresh water from lakes or rivers to the cities. Roman engineers constantly monitored the water levels and aqueducts to make sure that there was enough water for the city and the baths. They even had underground pipes and sewage systems. Wealthy people were able to have running water in their homes.