It is not uncommon for a water heater to make noise as it is heating water. PG&E recommends the following if your water heater is making noise:
Do you smell gas? If so, please evacuate the area and call us at 1-800-743-5000 and follow the prompts to report an emergency. We will send someone immediately to investigate and make the situation safe.
For an immediate response, please do not attempt to report a suspected gas leak on social media or by email.
If you DO NOT smell gas: Contact a licensed plumber for repairs. PG&E does not repair customer appliances.
Visit our Gas Safety page for more information gas appliance safety.