CTC water heater makes popping or rumbling noises during heating.

Safety first: Turn off power and allow the tank to cool before draining.

Steps to check:

• Connect a hose to the drain valve and flush the tank thoroughly until water runs clear.
• For electric models, remove and inspect heating elements for scale; clean or replace as needed.
• Consider installing a whole-house water softener or a scale reduction system if you have very hard water.
• Repeat flushing annually to prevent recurrence.