Water is said to be the mother of tea. Preparation of water is the heart of tea brewing. There are many things to consider but in brief the water needs to be 96-98 degrees for Pu ERh.
A traditional kettle will over-boil the water and so the tea brewer is advised to keep an eye on their kettle. I have many kettles but I recommend a glass kettle when getting started, so you can watch the size of the bubbles and control the strength of the boil.
Adding a gold or silver coin to the mix will improve the water quality if you don’t have a kettle made of the same substance.
Working on your water is the best way to improve your tea. Tea is very forgiving in steepology but water is not.

Erick Smithe