Question: When using an electric water cooker/boiler, how to translate the following:

> 
> The water is boiling.
> 
> 
> 

What would be arguably the most common way in Mandarin to say this in Taiwan?

Answer: 
> 
> "The water is boiling."
> 
> 
> 

We say 水開了 in Taiwan. Nothing else.

我們都說「水開了」，好像沒有人用其他講法。
Many ways to describe water boiling, depends on the situation, say temperature or some flow within, of water.

* 水開了：water has reached at 100°C
* 水滾了: water has reached at 100°C
* 水在沸騰: water is going up to 100°C

The first one is the most common way to describe the water is boiled already.