There are times when you want to do the dishes or are hopping in the shower only to find the water is still cold.

Usually, it warms up after a minute, but what about those times when the water refuses to get any hotter?

Thankfully, the most common causes of this problem can be easily diagnosed and solved by the average DIYer.

© fizkes / Fotolia

    Common Problems

    Many of the most common issues occur regardless of the type of water heater you have installed. The following issues are usually easy to diagnose and should always be considered first.

    This problem may require you to replace the entire tank if the source of the leak isn’t a valve or pipe connected to the tank. Be very careful when checking for leaks, as the water may be dangerously hot. Discovering water in the tank’s compartment is almost always a sign that the tank itself has begun to leak.

    Perhaps the most common reason for water to remain cold in a busy home is an empty tank. Water heaters work hard to heat an amount of water that fills the tank, but this tank has a limited capacity.

    Using too much of this hot water in a short time will empty the tank’s supply faster than the heating elements can replace it, leaving you with cold water. Most tanks require half an hour to build up a sufficient supply once drained.

    In the event this particular problem is happening frequently, you may also want to consider upgrading to a larger capacity heater. Water heaters are often installed based on an estimate of the demand for the current residents or future residents.

    This estimation may not remain accurate, however, as each family residing in a given building will have its own requirements.

    This problem occurs naturally and is often accompanied by a pinging sound if there is a lot of buildup. This sediment absorbs heat from the water, making it more difficult for the heating elements to do their job and shortening their life spans.

    You should regularly flush the tank to prevent sediments such as calcium from solidifying, which can destroy a tank over time.

    1. Turn off your water heater by shutting off power to the heater at the circuit breaker (electric) or setting the thermostat to the pilot setting (gas). For improved safety, you may choose to leave the heater off overnight.
    2. Locate the valve near the cold water inlet at the top of the tank. Ball valves require a 90-degree turn, while gate valves need multiple turns. In the event, your gate valve has a stop feature, be sure to turn past it.
    3. Open a hot water tap somewhere in the house to avoid a potential vacuum.
    4. Attach a garden hose to the drain valve or cock located at the bottom of the hot water tank. It may be either exposed or located behind a small cover panel. You may choose to use a bucket instead, but must be careful not to let it overflow. Additionally, cover the valve with a rag to avoid any spraying and avoid using cheap plastics, as these may warp or soften from the hot water.
    5. When transferring to a sump or drain instead of using a bucket, you may speed up the process by opening the pressure relief valve. This valve is generally located near the top of the tank and opens by flipping upwards.
    6. Open the drain valve, making sure not to apply too much pressure if a plastic drain cock is present, as it might break.
    7. Every few minutes, pause the draining process and fill a bucket. Let this sit for a few minutes and examine the bottom for any signs of sediment. Clear, sediment-free water means you may stop the process completely. Conversely, cloudy water or visible sediment on the bottom of the bucket means the tank is not yet fully flushed.
    8. Once you are satisfied that the water is clear, close the drain valve and the pressure relief valve if you have opened it. Then turn off the hot water tap and reopen the cold water valve and allow the tank to fill, so the pressure becomes equalized.
    9. Once you have filled the tank, open the pressure valve again to allow any excess air to escape. Close the valve and turn on a hot water tap until you are getting a normal water flow.
    10. Once these steps are completed, you may turn the thermostat or breaker back on. Your hot water taps should be producing warm or hot water again after about 20 minutes.

    Water heaters contain a built-in thermostat to regulate the internal water temperature. Adjusting this thermostat slightly may be enough to keep the water hot. Water that gets into the compartment for any reason may also cause the thermostat to short out. In the case of a damaged thermostat, you will need to replace it.

    Electric Water Heaters

    Electric heaters are prone to shorts and other issues common in electrical appliances. The following potential problems are among the most commonly found in an electric heater.

    Breaker, Fuse, and Reset Button

    A blown fuse or tripped breaker will quickly disable your heater.

    In most cases, resetting the breaker will be enough.

    However, frequent occurrences of this issue may require replacing the breaker or fuse with a higher amperage unit.

    Much like the breaker, a reset button that trips frequently will need replacing.

    © brizmaker / Fotolia


    Grounded components can short out the heater and even damage components. Check for any objects that may be causing wires to touch and remove them. In the event your heating element or thermostat is grounded, you will need to replace that component.


    A short in the wiring may not only prevent the heater from functioning properly but is also a fire hazard. Be sure to check all wires for signs of damage and replace as needed.

    Gas Water Heaters

    Gas heaters have several parts which make them different from electric heaters. In most cases, problems related to these components may be handled by the average homeowner with common tools.

    Pilot Light Assembly

    This assembly comprises the pilot light, thermocouple, and burner. Each of these parts has its own potential problems that can affect the heater’s performance. The most common issues are:

    • Blocked Flue – Debris from rodents or storms may block the flue, and air forced down can extinguish the pilot. Cleaning the flue can be messy, but is a straightforward task.
    • Clogged Burner – Soot can slowly build up on the burner over time, causing it to clog. This can hinder or even prevent the burner from functioning. Regularly removing and cleaning this element will help to maintain the heater’s efficiency.
    • Clogged Pilot – Much like the burner, the opening that feeds the pilot light may become clogged. Regular cleaning will help improve performance.
    • Thermocouple – This element’s tip should be in the pilot light’s flame, and the connection to the gas line must be secure. Check for kinks and replace the component, if needed.

    Supply Line

    There are several problems that may affect the supply of gas going to your heater, all of which may be remedied through a few simple tests.

    Begin by checking the supply like to make sure there are no pinhole leaks or other damage, and that the line isn’t kinked.

    A damaged line should be replaced immediately to prevent the risk of fire or explosions. Next, make sure the gas valve is in the on position, and your gas isn’t shut off.

    © Jo Ann Snover / Fotolia

    A faulty gas valve must be replaced, but this task can be performed by most homeowners at little cost. Finally, re-light the pilot light several times to ensure there’s no air in the line.

    Think you might need professional help with your water heater? Use the form below to connect with local plumbing pros:

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    Henry Parker

    Henry Parker is a home improvement enthusiast who loves to share his passion and expertise with others. He writes on a variety of topics, such as painting, flooring, windows, and lawn care, to help homeowners make informed decisions and achieve their desired results. Henry strives to write high quality guides and reviews that are easy to understand and practical to follow. Whether you are looking for the best electric riding lawn mower, the easiest way to remove paint from flooring, or the signs of a bad tile job, Henry has you covered with his insightful and honest articles. Henry lives in Florida with his wife and two kids, and enjoys spending his free time on DIY projects around the house. You can find some of his work on Today’s Homeowner, where he is a regular contributor.

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