Serving Greenwood, Fishers, Carmel, Indianapolis & Surrounding Areas

March 10, 2023

Rusty Water Coming from Hot Water Heater: 4 Possible Causes

Discolored water from your faucet is alarming and may indicate a problem with your hot water heater. Complete Comfort Heating, Air & Plumbing can identify the source of rusty water and fix the problem. Call (317) 563-8122 for an appointment.

Whenever you turn on a faucet, you expect clean, clear, and fresh water to flow out. When rusty-looking or brown water comes out instead, it’s normal to have concerns about a plumbing problem and water safety. Rusty water coming from the hot water heater, in particular, requires prompt attention, as there’s a good chance you’ll need a new one very soon. 

As Greenwood’s water heater services leader, Complete Comfort Heating, Air & Plumbing can quickly diagnose the source of discolored water and recommend cost-effective solutions. A high-quality water heater can last for decades, but rusty water is often a surefire sign that it’s time for a replacement. In this blog, we offer some troubleshooting tips to help you narrow down the cause of rusty water from your faucets and some potential solutions, including when to invest in a new water heater. 

Identifying the Cause of Rusty Water 

Uncovering the cause of rusty water starts by noticing when it occurs.

If only cold water appears rusty or discolored when you first turn on the tap, the problem is likely due to corrosion in the plumbing lines. This issue is most common in galvanized steel pipes, which corrode on the inside over time. Re-piping, or replacing the pipes, is the only solution, as the corrosion will only continue to spread.

If discolored water comes from both the hot and cold water taps, and doesn’t clear up even after running the water for a few minutes, then the issue is likely something in your water supply. A broken water main or seasonal hydrant flushing can cause the water to turn brown until the dirty water clears. In most cases, you’ll know in advance when the city schedules hydrant maintenance, and they will provide instructions on ensuring you have safe water. 

If the rusty water only comes from the hot water tap, you have a problem with the water heater. You need to call a plumber to check out the heater and identify the specific reason for the rusty water.

The Most Common Causes of Rusty Water Coming from Hot Water Heaters 

When you have rusty water coming from the hot water heater, call a professional right away to identify the source of the rust and make repairs. Sometimes, a plumber can alleviate the problem, although the solution is most likely temporary.


Corrosion inside the hot water tank is the most common cause of rust-colored water from the tap. The inside of the tank is metal, and constant exposure to water can cause rust over time. The older the water heater, the more likely a corroding tank is the reason for discolored water.

Rust on the tank’s exterior is another telltale sign that the inside of your water heater tank is deteriorating. Under normal conditions, there is no reason for a water heater to have exterior rust spots. If you spot corrosion on the outside of the tank, that usually means that the inner part is leaking due to a crack or other related damage. 

In any case, the only solution for an excessively corroded hot water tank is replacing it with a new one. The corrosion will only worsen over time, as will the discoloration of your water supply.

Sediment Buildup 

Over time, sediment accumulates in the bottom of water heater tanks, and this can eventually cause water discoloration. Hot water tanks need ongoing maintenance, including draining and flushing, to prevent excess sediment buildup. If you suddenly have rusty water coming from the hot water tap, this service may solve the issue. 


Certain bacteria within the water supply can also give water a rusty appearance. Plumbing lines and the hot water tank contain certain types of iron-reducing bacteria, and if the water doesn’t move enough or contain enough oxygen, that bacteria can speed up corrosion and give the water a rusty appearance. 

When bacteria discolor water, shocking the water system with a chlorine treatment and flushing the system can solve the problem. However, excessively corroded water heater tanks and pipes need replacing to prevent ongoing issues.

Failing Anode Rod 

A failing anode rod inside the water tank can also be the source of rusty water. The anode rod attracts corrosive particles from the water inside the tank, preventing them from interacting with the metal in the tank and contributing to corrosion. Most anode rods last for about five years before needing replacement, so if you have rust in your hot water, replacing the rod can slow the corrosion. 

Anode rod inspection and replacement (when necessary) are usually included in a water heater maintenance visit. Replacing the anode rod, in addition to draining and flushing the tank, can eliminate rusty water and help extend your water heater’s lifespan.

Should I Worry About Rusty Water? 

When the water coming out of the faucet is anything other than crystal clear, it’s reasonable to have concerns about whether it’s safe. 

The short answer is that the U.S. Environmental Protection Agency deems water that contains enough iron to discolor it, give it a metallic taste, cause rust stains, or lead to sediment buildup safe for human consumption and exposure. It may not be preferable or desirable, but rusty water won’t cause lasting harm to you or your family.

That said, if you notice rusty water coming from the hot water heater, it’s best to call a plumber for help as soon as possible. Rusty water can stain your fixtures and laundry, and it’s not good for your skin and hair. Eliminating the source of the rust or replacing the water heater can solve the problem and prevent inconvenient stains or discomfort. 

Prevent Rust Water with Maintenance 

Water heater maintenance can prevent many problems that lead to failure and issues like rusty water. We recommend a professional maintenance visit at least once a year that includes draining and flushing the water tank and an inspection and service of the mechanical parts. A professional technician can identify the signs of deterioration and corrosion before they cause rusty water to flow from the tap and answer questions like, “how long does a water heater last?” so you can plan for a replacement.

Trust Complete Comfort Heating, Air & Plumbing to Solve Your Water Heater Issues

Whether your water heater uses gas or electricity, corrosion is inevitable. At the first sign of any issue with your hot water, call a plumber to ensure that the problem doesn’t worsen. Replacing the appliance is the only way to stop rusty water permanently, but our licensed, bonded, and insured plumbers can sometimes make repairs that temporarily solve the issue and restore your clean water supply.

Greenwood, IN, homeowners trust Complete Comfort Heating, Air & Plumbing for all their plumbing needs. If you have rusty water coming from the hot water heater, call us at (317) 563-8122 to arrange for one of our experienced plumbers to diagnose and solve the problem. Our family-owned company has a reputation for exceptional customer service and quality work that exceeds expectations, so you can trust that you’re in good hands.

Don’t forget to ask about our maintenance plans, too. Complete Comfort Heating, Air & Plumbing’s convenient plans offer peace of mind and save you money on heating, cooling, and plumbing services.

Author Bio:

Brittany Katterjohn

Brittany is a marketer, entrepreneur, and writer with previous business development experience in the home maintenance industry. She currently manages the marketing for Complete Comfort Heating, Air & Plumbing and has a passion for helping people by simplifying seemingly complicated topics related to home maintenance and repair.

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