Discolored Hot Water in Your Building: What Does it Mean? – Sobieski Services | DE, NJ, PA, MD

Discolored Hot Water in Your Building: What Does it Mean?

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When someone in your facility turns on the hot water supply, they naturally expect a flow of clean, clear water. That’s why it’s such a surprise when hot water comes out of the faucet discolored. This isn’t a reason to panic, but it’s certainly a cause for concern. Solutions for resolving plumbing problems involving discolored hot water can be as simple as waiting for a while or as complex and expensive as replacing a pipe system. Before taking any steps, you need to know what’s causing the discoloration. Here are some of the more common causes of discolored hot water.

Sediment and Mineral Buildup

Probably the most common cause of discolored hot water is sediment and mineral build-up inside the heater. Sediment is solid material contained in the water that has settled to the bottom of the water heater tank. Mineral build-up occurs as minerals in the water cling to the sides of pipes or the inside of the tank, accumulating over time. Both of these problems can produce discolored hot water. Accumulations of these materials can affect how well the water heater functions, reducing its efficiency and effectiveness in generating the hot water your facility needs.

The usual solution to this problem is to flush the hot water heater’s tank. This involves draining all the water from the tank and running water through the system to flush out sediments and minerals. In many cases, flushing the tank can resolve issues with hot water.

Keep in mind that solid mineral buildup inside the water heater can be difficult to remove. The accumulating minerals will restrict water flow and affect heater performance. Eventually, it is likely that the minerals will accumulate so badly that the heater will need to be replaced.

Rust and Corrosion in the Pipes

Older pipe systems are sometimes made of galvanized iron pipes. These pipes can begin to rust or corrode as they age. When this happens, particles of the rust can break off and enter the water supply, causing discolored hot water. Newer piping systems that use plastic or copper pipes will not have this kind of problem.

When the pipes in your plumbing system regularly cause discolored hot water, the best solution may be to replace the pipes completely. This is a time-consuming process that will probably require excavation to uncover affected pipes.


There are certain types of bacteria that can get into a water supply and cause discolored hot water. These iron-reducing bacteria literally eat iron–not by taking bites out of it, but by oxidizing the iron. The byproduct of this oxidation process is what causes the discoloration in your hot water supply.

The problem can often be resolved by adding chlorine to the water to kill the bacteria.

Bacteria-based hot water discoloration may not be an issue in facilities that use a municipal water supply. These iron-eating bacteria are usually found in smaller water sources such as wells. It is possible that some smaller or older commercial buildings, or facilities in a more rural setting, may rely on a well for water.

Water Supply Problems

Sometimes discolored hot water can be caused by disturbances or problems in the municipal water supply. Water testing, flushing fire hydrants, and pipe issues are a few of the sources of water discoloration in municipal systems. When this happens, check the cold water too. If the cold water coming from the faucet is also discolored, the most likely source is a problem in the municipal water system. The discoloration will most likely go away in a few hours. If it doesn’t, call your local water utility for assistance.

Our goal is to help educate our customers about Plumbing, HVACR, Fire Protection, and Alarm Systems in Mechanical, Commercial, and Residential settings. For more information on the causes of discolored hot water, or to view projects we’ve worked on, visit our website!

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