The difficulty of storing something very heavy (i.e. water) at a great height is the leverage the mass can exert on its foundations. Water towers are prone to settling alarmingly if their foundations fail. The leaning water tower of Britton Texas is a widely reported (but deliberate) example of a leaning water tower but the tilt in the water tower of Teluk Intan in Malaysia was caused by a stream under its foundations. Wikipedia says:
...erected in 1885 by a Chinese builder, Mr. Leong Choon Cheong. It started to tilt four years after its construction finished due to an underground stream. The tower had a clock at the top, and still rings every 15 minutes now. The clock tower was originally used as a water tower, supplying water to the town area, while also reporting the time to all townfolks. It had also served as a beacon to guide ships into Teluk Intan Port. Currently it is a local tourist attraction, and no longer stores water. The area around the tower was paved with bricks and became a plaza. The main street at the centre of Teluk Intan is also named after Mr. Leong Choon Cheong to commemorate his contribution. The name of the street is "Jalan Ah Cheong"
The image here is lifted from travel blogger Aminyunus
who shares his memories of the tower.