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The Home Depot

Why Is My Hot Water Yellow?

Pro Referral > Home Guides > Plumbing > Why Is My Hot Water Yellow?
Why Is My Hot Water Yellow?

Apart from the fact that yellow hot water is visually unpleasant, it can also be unhygienic to use. As such, the cause of the yellow hot water needs to be identified and repaired so that your family and guests can utilize the water again. The first step to isolating the cause of the discoloration in the water is to check the cold water quality. If the cold water coming from the taps and faucets is clear, you can determine that the problem involves the water heater and not the main water supply.

  1. 1.Sediments in Water Heater Tank

    Since water heater tanks store water until it is heated, they accumulate sediments of minerals at the bottom. Over time, this can lead to an abundant presence of sediments that turn the hot water yellow. In order to clean the tank of the water heater, it needs to be flushed out. This is achieved by reversing the flow of cold water into the tank at a high pressure before flushing it entirely. This process will dislodge the sediment and ensure that the tank is cleaned.


    Sometimes, the body of the water heater tank can rust inside and release iron into the water, leading to yellow water coming out. If you suspect that this is the case, you need to change the water heater to eliminate the problem and obtain clear, heated water.

  3. 2.Iron Bacteria

    While sediments can cause yellow water to appear from your water heater, another cause of yellow water can be the presence of iron bacteria. These bacteria thrive in water with a high concentration of iron, no oxygen, and low temperatures. If the water you receive from the municipal supply or well has a high iron content and the bacteria were present, they could multiply rapidly when the water heater is not switched on. The yellow color in the water is caused by the digestive process of the bacteria.


    If your water heater tank has been cleaned and the discoloration persists, it could be caused by the bacteria. To kill the bacteria present in the water heater you need to flush it with chlorinated water. Once all of the bacteria have been killed, you will be able to enjoy clear water again.


    When chlorinating to eliminate the iron bacteria you need to take steps to ensure that the pipes that transport water to the heater are also treated to eliminate recontamination of the heater.


    The presence of iron bacteria in the water heater can cause premature failure of the anode rod. As such, this should be checked and replaced if necessary once the bacteria have been eliminated.


    Another concern with the presence of iron bacteria is that most water heater manufacturers will consider it an external cause and not a problem with the heater. Unfortunately, any warranties for the heater will not be applicable when fixing this problem.

  5. 3.A Problem That Should Not Be Ignored

    A tub of yellow hot water is not as inviting for a soak, neither is a spray of yellow hot water when you are looking forward to a quick shower. Yellow water can be a turn off and only leads to frustration. This is why alleviating and solving the issue will not only boost your spirits, but it will help to eliminate any potential health problems as well.

  7. 4.Retain a Reliable Plumber to Fix the Problem

    Whether you are a busy homeowner or unsure about how to tackle the plumbing, you can ensure that the quality of hot water you and your family use is clear and safe by retaining the services of a qualified and reliable plumber.

As a responsible homeowner you need to ensure that the water quality in all the taps and faucets is remarkable. Discolored water is a visual indication of contaminated water. If the hot water from taps and faucets in your home is yellow, you need to examine the water heater tank for sediments or bacteria even if the water is odorless. Sediments in the water heater tank need to be flushed out, while water contaminated by iron bacteria needs to be subjected to chlorine shock. The chlorination needs to cover the pipes as well to ensure that there is no chance of recontamination. A reliable and dedicated plumber will be able to clean the water heater tank of sediments and also carry out the chlorination. If the water has been contaminated by iron bacteria you also need to ask the plumber to replace the anode rod.

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