I saw a video where people referred to to Chinatown in Singapore as 牛车水. What does this literally mean?
牛车水 literally means
牛车 - oxcart 水 - water
i.e. 牛车（运）水, oxcart (carrying) water.
There's no tap water in the past, it was general to transport water by oxcart in chinatown, as time passes chinatown began to be called as 牛车水.