'Luxury' 2,700-year-old toilet discovered in Jerusalem
https://edition.cnn.com/travel/article/ancient-toilet-jerusalem-scli-intl-scn/index.html
Roman Empire had toilets which can be flushed by water. But in middle-eastern nations, it's difficult for them to get water. So, such types of toilets are not feasible. That would be why the toilet found in Jerusalem does not have a deep septic tank.
