The answer is aqueducts.
Romas constructed aqueducts to avoid that cities and town would take the water from the rivers they used for waste. Aqueducts supplied them with fresh water in kitchens, public baths, latrines, fountains, gardens, private households, milling, farms and mining operations,
Its first aqueduct was made in 312 BC and it supplied a water fountain at the city's cattle market. Eventually, Romas significantly increased aqueducts' construction, seeing as very expensive but very necessary for people, and became one of the main public interests.