Is there anything more annoying than turning on the hot water tap and getting a lukewarm trickle instead of nice steaming hot water? It's incredibly frustrating when the hot water heater stops working properly. But don't panic! In most cases, it's an easy DIY fix.
This guide will walk you through the 6 most common reasons your hot water heater might stop heating water properly and simple steps you can take to get it working again. With a little troubleshooting, you can have your hot water back in no time.
Cause #1: Gas Leak
If you have a gas water heater, the first thing to check is whether you have a gas leak somewhere. Gas leaks are very dangerous, so this should be your number one priority.
Here's what to look for:
Loose connections - Check where the gas line connects to the water heater. Make sure everything is tight and sealed properly with no gaps. Tighten anything that looks loose.
Hissing noise - If you hear a hissing or whistling sound around the water heater, that's a telltale sign of a gas leak.
Rotten egg smell - Natural gas has a distinct "rotten egg" type odor added specifically so you can detect leaks. If you notice that smell around your water heater, there's a leak.
Turn off the gas supply immediately if you suspect a leak! Then call a professional to inspect the gas line and make repairs. Don't turn it back on until you're 100% sure the leak has been fixed. Gas leaks can cause explosions and carbon monoxide poisoning, so it's incredibly dangerous to ignore them.
Once the gas line is secure with no leaks, relight the water heater pilot light according to the manufacturer instructions. That should get your hot water going again.
Cause #2: Broken Dip Tube
Inside your water heater tank is a long plastic tube called a dip tube. Cold water enters through the dip tube, which takes the water to the bottom of the tank to be heated.
If the dip tube gets damaged or cracked, it can't deliver the cold water properly. Instead of going to the bottom, the cold water mixes with the hot water at the top of the tank. This results in lukewarm water coming through your faucets.
Replacing a broken dip tube is a fairly straightforward DIY fix:
Drain the tank - Turn off power to the water heater. Attach a garden hose to the drain valve and route it to somewhere safe. Open the valve to drain all the water out.
Remove old dip tube - Once drained, you'll see the top of the tube. Twist to loosen it, then pull it out.
Get replacement tube - Take the old tube to the hardware store to ensure you get an identical replacement.
Install new dip tube - Carefully insert the new tube until it's fully seated at the bottom of the tank.
Refill tank - Close drain valve, refill tank, and turn heater back on.
After installing a new dip tube, your hot water should be back to the proper temperature.
Cause #3: Clogged Air Intake Screen
Your water heater requires air intake through a vent or combustion chamber. This allows oxygen in for the pilot light. Over time, dust, lint, and other debris can clog up the air intake screen on the vent.
If the screen gets too blocked, it restricts air flow. Without enough oxygen, the pilot light will go out and the burner won't ignite. No ignition means no hot water!
Cleaning the air intake screen is fast and easy:
Locate the screen - It's usually on the bottom of the water heater or combustion chamber.
Gently brush debris - Use a soft brush to clear dust and lint from the screen. Avoid damaging the screen.
Use compressed air - For stubborn clogs, hit the screen with short blasts of compressed air.
Vacuum remains - Use a crevice tool on the vacuum cleaner to remove any remaining debris.
With the air intake screen cleared, oxygen can flow freely again. Relight the pilot light, and you should have hot water.
Cause #4: Faulty Thermostat
The thermostat controls the temperature of the water inside the tank. When it stops working properly, you may experience:
Water not heating at all
Water heating inconsistently
Inability to control temperature
Before replacing the entire thermostat, do some simple checks:
Adjust temperature - If set too low, bump it up and wait 30 minutes to see if water reheats.
Test with multimeter - To see if it's providing continuous power, test voltage on the thermostat wiring.
Replace thermostat - If faulty, you'll need to turn off power, remove old thermostat, wire up new one, and turn back on.
Replacing a bad thermostat yourself is totally doable. But if that doesn't restore hot water, then the problem lies elsewhere, and you'll need to call a technician.
Cause #5: Tripped Water Heater Breaker
Electric water heaters have a high-temperature limit switch that shuts off power if the tank overheats. It's a safety mechanism to prevent dangerous pressure buildup.
But if it trips when there's no actual overheating problem, you'll be left with lukewarm water.
Here's how to reset a tripped breaker:
Locate breaker - It will be on the water heater itself or on your main electrical panel.
Flip breaker off - Completely shut off the breaker before attempting to reset it.
Press reset button - There will be a small red or yellow button on the breaker marked "Reset." Press firmly.
Flip breaker on - Return breaker to the ON position.
Test water temp - Give the tank 30 minutes to reheat the water, then check your hot water temperature.
If the breaker was tripped for no reason, resetting it should restore your hot water supply. But if it trips again shortly after, contact an electrician to inspect for underlying issues.
Cause #6: Faulty Heating Element
Electric water heaters use one or two heating elements submerged in the tank to heat the water. If the element fails, you'll get decreasing or lukewarm water.
Troubleshoot heating elements with these steps:
Drain tank - Turn off power and drain the tank completely so you can access the element.
Remove cover - Take off the electrical cover plate to expose the heating element.
Check for cracks - Visually inspect the element for any cracks or damage. Elements can corrode over time.
Test resistance - Use a multimeter to test the resistance between the two contacts on the element. Consult the manufacturer specs, but it should be between 5-25 ohms.
Check for power - Verify power is reaching the element by testing voltage at the contacts.
Replace if needed - If resistance is way off or the element has visible damage, you'll need to replace it. Make sure to get an identical model.
Reinstall - Screw in the new element securely, replace the cover, refill the tank, and restore power.
If the old element tests fine and you're still having hot water problems, there's an issue with one of the other components that will require a professional repair. But replacing a faulty heating element is an easy DIY task that can often get your hot water flowing again.
Having lukewarm or intermittent hot water is super annoying. But in most cases, you can troubleshoot and fix the problem yourself without waiting for a plumber.
The most common culprits are gas leaks, broken dip tubes, clogged air intake screens, faulty thermostats or heating elements, and tripped breakers.
Work through these potential causes one by one, starting with any safety issues first. With a systematic approach, you'll likely find and resolve the issue in no time. Just be sure to turn off power and water supply before attempting any repairs.
If you try all the DIY troubleshooting steps and are still without hot water, then it's time to call in a professional. Some problems like tank leaks require more advanced skills.
But for most hot water heater malfunctions, a little DIY tinkering can get your hot water flowing again - saving you time and money!