As with other Roman cities, Pompeii had an excellent sewage system. However, it did not, with a few exceptions, reach above the ground floor of buildings, so people living on upper floors would simply throw their slop into the street, where an open sewer, culver or gutter would eventually wash it away (the smell must have been terrible, not to mention the health risk). People on the ground floor or single story buildings would pour water into the latrine or toilet and it would get flushed down into the sewer. Roman sewers were well built and effective.