In larger Roman towns, people often got sick or died from drinking water that had been contaminated with sewage. Sewage is human waste - poop or pee. When people drink water with poop in it, they can get other people's germs and get sick with dysentery or die. To fix this problem, many Roman towns built aqueducts to bring in fresh water from the hills outside of the towns. They also built public latrines and systems of sewage pipes to carry sewage out of the streets and dump it into the river. This was a big improvement on Greek sewage arrangements, where people just poured their waste into the street however they wanted.
Public latrine at Ostia (Thanks to Lynn Lichtenbaum)
There were also big public toilets that had room for lots of people at the same time (this one is from Ostia). Unlike latrines in China, in Rome people sat down to go to the bathroom. (Even today, most people in China still use squat toilets rather than seats, while most Europeans still sit down.)
These sewers just dumped raw sewage into the river, which was better than leaving it lying around in the streets, but still did spread germs sometimes. The Romans didn't have any way of treating sewage to kill the germs, as we do today, and they didn't understand the need to do that.
Street drain in a Roman street
Roman clay drainpipe
Some of these sewers are still being used today.
In smaller towns, though - most of the towns in the Roman Empire - there weren't any sewers, and sewage collectors came through and got the poop from each house and carried it off to sell to farmers to use as fertilizer on their fields, just like in ancient China at the same time. In small villages (where most people lived), they didn't even have outhouses, and people just walked out to the fields every morning and pooped there.
Roman water and sewage systems were the forerunners of the sanitation systems we have today that keep people’s water clean and safe. Today the city of Rome has been joined by newer cities like London and New York City in maintaining healthy water supplies, and new street cleaning services keep the streets and buildings much cleaner than they were in Ancient Rome. Big companies in the cleaning industry like New York’s Janitorial Cleaning Services work to find chemicals and supplies that will clean offices and workplaces safely. But it all started with Roman aqueducts and sewers.
For more information about the cleaning industry, click here - http://www.commercialofficecleaning.com/ For more about ancient Roman water and sewage, check out these books:
City, by David Macaulay (1983). A detailed description, lavishly illustrated, of the construction of a Roman town. Incredibly accurate. Highly recommended for anyone young and interested in ancient Rome.