Common Hot Water Tank Problems

by | Dec 19, 2023 | Water Heaters and Tanks

There are many common hot water tank problems that arise for home owners. Some can be attributed to the water heater, others to the hot water tank. In this post we’ll detail the most common of problems, and some general guidelines on what you can do next to solve the problem.

Water leaks

The most common leak problems occur due to condensation on the water heater. However there could be leaky water supply lines or leaky pipes above or around the water heater. Typically if your water heater is leaking it is cracked or corroded. Loos or fault fittings and pipe connections could also be a problem. The pressure relief valve would be another item to check.

No pilot light

If your pilot light won’t stay lit then some common reasons include the following:

  • The thermocouple needs replacement, or the thermocouple connection is loose.
  • If there is air in the gas line this can stop the pilot light from igniting.
  • If the pilot light tube is dirty you can clean it with a dry cloth and sandpaper.

Other pilot light problems

  • Low gas pressure can cause a pilot light to be too small.
  • If the pilot burner is undersized the pilot light could be too small.
  • A clogged pilot light can also cause too small of a pilot light flame.
  • If the pilot light flame is too large that’s usually because there is too much gas flowing into the pilot light, so this could be a problem with your gas provider.

Low water pressure

Low water pressure specific to hot water demands for your building or home can be caused by a few problems. Firstly, your pipes or faucets may be clogged. Sediment, rust, calcium deposits or other miscellaneous debris can build up in the faucet or plumbing lines. Secondly your water flow control valve may be partially closed, this is usually the case where your home is affected by low hot water as opposed to both low cold and hot water. Finally, and most critically, you may have leaky or broken pipes. You can check your carpets, flooring, or walls for leaks.

No hot water

There could be a number of reasons you are not getting any hot water. For instance, a lack of power or gas supply to your water heater. If the temperature has dropped low enough lines may freeze. If this is the case the lines must be thawed before water can be heated again. If the pilot light is on, but water is not heating properly, get a hold of a professional hot water tank plumber to inspect your water heater and tank.

Rusty water

Rusty or discolored water is caused by corrosion of the inner tank lining. This is generally cause by a decrepit anode rod. If you are getting rusty discolored water then consider replacing the anode rod. Flush and clean the hot water tank system. If the problem persists, it’s time to get a professional to weigh in.

Faulty heating element

Generally if your water temperature is inconsistent your water heater element is faulty. Another common sign of a faulty water heating element is when your circuit breaker repeatedly trips. This can be caused by your faulty heating element drawing too much electricity. Your water heating element may have built-up minerals or calcium.

Changing water temperatures

Water temperatures are a frequent problem with water heaters. Either the water is too cold, not hot enough, or too hot.

  • Water is cold – Completely cold water can be caused by a number of things. Most likely it is a faulty thermostat or a faulty heating element. To ensure that electrical problems are not at fault, reset any breakers, and replace blown fuses. You can also check the thermostat to ensure it is getting sufficient power. Cold water can also be due to a faulty anode rod.
  • Water is not hot enough – If the water is warm, but not getting hot enough for your liking this could be caused imbalanced water mixing, or faulty heating element. It could also be the case the thermostat is malfunctioning. There is also the potential that your water heater is simply undersized for the tank and draw of the building or household.
  • Water is too hot – If water is too hot then usually the thermostat is set too high. You can check your hot water tank and heater manual for necessary adjustments to temperature.

Mineral deposits

Over time of hard water usage in most hot water tanks mineral deposits will build up inside the water heater. This can cause a number of issues, one being faulty temperature sensor readings, causing the water heater to heat beyond a safe level. Calcium is the general culprit, and mineral deposits such as calcium can also affect water heater efficiency, causing higher than normal energy bills. To solve the problem start by flushing  the tank. You can then use a descaling solution to remove some of the calcium form the tank. It may be necessary to replace the water heater element or clean it if it has too much calcium mineral deposit build up. It could also be good idea to invest in a water softener system. A water softener system will work to intercept all the calcium prior to it getting into a water heater.

Sediment build-up can also be avoided by flushing and draining the water tank. This will prevent sediment from remaining inside the tank.

Thermostat malfunction

Common signs of thermostat malfunction are no hot water, hot water not meeting household or building demands, water that is too hot, or long wait times for your tank to reach temperature. It’s common with thermostat malfunction that you’ll have to reset the high-temperature limit switch.

Leaking drain valve

A loose drain valve can cause leaking. This can be cause often by worn-out plastic or a failing gasket. Hot water tank drain valves are often made of plastic and over time, this plastic can become brittle. Consider replacing the drain valve if it is leaking frequently and you have replaced the gasket.


If you are noticing odd noises coming from your hot water tank this is usually the result of sediment build-up. The sediment circulates and makes contact with the metal housing of the tank and through the water heater, causing noise when hot water is being drawn from the building plumbing or when the heater is maintaining temperature. Try flushing the hot water tank, and if the problem persists, it may be time to replace the water heater.

Different types of noises

Ticking – Changes in water pressures can cause ticking noises or pipe rattles. Go around and tighten loose pipe straps or replace them. Ticking noises can also be caused by efficiency-boosting heat trap nipples.

Screeching or singing – These sounds, like a boiling kettle, are typically produced when water flow through a valve is significantly restricted.

Water hammering – Water hammer refers to a hammering or banging noise produced by a plumbing system, when water is forced to change direction or stop abruptly.

Rumbling – Mineral deposits and sediment build-up settling inside the tank can cause a range of problems. The water in the tank heats and expands, and pushes the sediment to the top of the tank, hitting the sides and bottom of thank, creating a rumbling sound.’

Popping – A popping sound can be caused the anode rod, within the tank, if it is exposed to high alkalinity levels.

Failing anode rod

A failing anode rod can cause a rotten egg smell when you run hot water. As the rod deteriorates, this triggers a reaction between the water tank’s bacteria and the supply of water. A faulty anode rod can also cause inconsistent water temperature or no hot water whatsoever. A metallic taste in the water could also cause a corroded anode rod.

A failing anode rod can also cause rusty or muddy water. If your water has a metallic taste, this could suggest a corroded anode rod. The best way to determine if an anode rod is a physical inspection. You might need to drain some water from the tank to make a visual inspection, and unscrew the anode rod.

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Damaged pressure relief valve

A damaged pressure relief valve can cause leaks. Usually the case is that the pressure relief valve is not fully closed. There could be debris in the pressure relief valve, that prevents it from closing fully. Abundantly hot temperatures can deteriorate the pressure relief valve over time, reducing the ability of the pressure relief valve to properly close. Sometimes your pressure relief valve is simply not sized properly and leaks.

Condensation on the water heater

Condensation on a water heater will usually show itself in spring and winter, when the water is the coolest. The water heater has to work harder to keep your water temperatures maintained where you desire them. As cool water enters the tank it causes surrounding water air vapor to condensate, collecting as moisture on the tank. Leaving condensation on the tank can lead to mold or mildew build-up. Dry up condensation if you see water pooling.

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