The water heater in your home is one of the most-used appliances in your house, accounting for around 18% of your total energy use. You probably use it every day for showers, baths, laundry, and dishes. Don’t take your water heater or plumbing system for granted. There are a number of problems to watch out for, such as a rumbling water heater.

A rumbling water heater is a common call that we get from our customers. If you’re having any type of problem with your water heater and you’re in the Birmingham area, contact OnTime Service.

Rumbling is a bad sign, but there may be an easy fix, such as flushing the tank of sediment. Learn why your water heater is rumbling plus how to fix it.

Causes of Water Heater Rumbling

There are a few different issues that may be causing the water heater to rumble:


While the water that comes from your utility is normally very clean, it can still have minerals and sediment (calcium, lime, etc.) in it. When the water enters your water heater, the sediment settles on the bottom.

Over time, sediment and minerals can really build up. This can block the heat from reaching the the water. When the sediment heats up, water inside the spaces boils and bubbles, creating a lot of movement, hence the rumbling.

This is the number one cause of a rumbling or knocking water heater.


You will need to flush the water heater.

You can either do it yourself or contact a professional plumber.

Sediment can easily be drained through the drain valve at the bottom of the tank.

Turn off the gas and water supply
Attach a drain hose to the valve and discharge it to an outside drain or driveway. If you don’t have a hose, you can empty the water into a bucket, just make sure it is large enough and can handle the high heat. You can also wait until the water to cool down before flushing it.
Open the drain cock at a rate where you can safely manage the water flow.

Warning: You are dealing with hot water! Hot water can hurt you, kill plants and grass, crack porcelain, and cause property damage. Consider waiting for the water to cool.

Read your owner’s manual. If you have any doubts, contact a professional plumber.

How often you flush your water heater depends on how many minerals are in the water and the condition of the tank (at least once a year).

Get to a point where it’s only a bucket of cloudy water between drawings, probably once every 3-8 months.

Cold Water

Your water heater likely has a dip tube that runs from the top of your water heater to the bottom. Cold water from your water main enters this tube and gets deposited at the bottom of your water heater.

If there is a leak at the top of the dip tube it can mix with the hot water near the top, which could cause rumbling when the cold and hot water meet.


Contact a professional plumber. Broken dip tubes are a common water heater problem.

When your water heater starts to rumble in the Birmingham, CO area, call the water heater repair experts at OnTime Service.

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