What kind of part can i get to detetec very hot water?
You want two things if I understand it correctly
- detect HOT water
- its level
1 ==> If you have this DS18B20 - http://arduino-direct.com/sunshop/index.php?l=product_detail&p=151 - you have a water proof one sensor for detecting HOT water
2 ==> John Wasser answered that one above, but
What temperature is the hot water?
==> Some magnetic effects may disappear (permanently) at high temperatures.
Can you tell more about the project?