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19 Common Hot Water Heater Problems: 140 Years of Expertise Reveals the Fixes 🛠️
If you’re like most people, you only think about your water heater when it stops delivering hot water on demand. But this hardworking appliance needs regular maintenance to function safely, operate efficiently, and last longer.
For over 140 years, since 1885, Water Heater King has been answering your toughest hot water questions. If your hot water heater is acting up, we have the answers. Below are the 19 most common water heater FAQs—and what to do about them.
Part 1: Water Leaks & Temperature Troubles
1. Water is Leaking from the Top
Don’t panic! This usually signals a fixable issue, not a tank replacement.
Possible Causes:
A loose cold or hot water pipe connection.
A leaking Temperature and Pressure (T&P) relief valve.
A faulty inlet valve.
The Fix: All of these connections and valves can typically be repaired or tightened.
2. Water is Leaking from the Bottom
⚠️ WARNING: This is the one to watch out for, as it can indicate a tank failure.
Possible Causes:
A leaking T&P relief valve (reparable).
A faulty heating element gasket in electric water heaters (reparable).
The Tank itself is leaking.
The Fix: If the tank is leaking, the unit is compromised and must be replaced. Consider upgrading to a new, energy-efficient model.
3. No Hot Water – Electric Heater
The Fix:
Check and reset or replace the main electrical breaker for the water heater.
If that fails, you likely have a defective thermostat or heating element.
4. No Hot Water – Gas Heater
The Fix:
Ensure the gas supply line is turned on.
Check if the pilot light is lit (you’ll need to remove the burner access covers).
The gas burner may be dirty or faulty.
5. Not Enough Hot Water
This is often a maintenance issue or a simple setting problem.
The Fix:
Check the thermostat setting—it might be set too low. CAUTION: A hotter setting can cause scalding within seconds.
Inspect the dip tube. If it’s broken, incoming cold water is pulled out without being heated.
Other issues include clogged burners, low gas pressure, faulty electric elements, or excessive scale buildup(common in older units). Try flushing the water heater to clear sediment.
6. Slow Hot Water Recovery
Possible Causes:
Sediment buildup at the bottom of the heater. Flushing may help.
Insufficient ventilation (insufficient combustion air).
A clogged flue (could be dangerous—potential for carbon monoxide poisoning!).
Improper burner operation.
Part 2: Gas Heater Issues (Pilot Light & Burner)
7. Pilot Light is Lit, But the Burner Won’t Ignite
The Fix:
Turn on a hot water faucet and let it run. Check if the burner comes on after several minutes.
Ensure the gas control valve knob is in the “On” setting, not “Pilot.”
If it still won’t come on, the problem is likely a defective safety system component. Call a professional.
8. Pilot Light Won’t Stay Lit
The Fix:
Ensure burner access covers are in place to prevent drafts.
Check for dirt/debris in the gas line or a problem with the thermocouple/gas safety device.
9. Pilot Light is Not Lit
The Fix:
Carefully follow the relighting instructions posted on your unit. Make sure the gas valve is open.
If it won’t relight, gas may not be reaching the heater, or the pilot line is clogged.
If the pilot lights but goes out when you release the gas valve control, it’s often a defective or loose connection in the pilot safety switch.
If unable to relight, call a licensed plumber for help.
10. Noisy Gas Burner Flame (Whistling)
Possible Causes: Improper gas pressure or a dirty burner orifice.
11. Yellow Gas Burner Flame
A yellow flame is inefficient and potentially dangerous—it indicates incomplete combustion.
Possible Causes: Scale on top of the burner, a dirty burner orifice, a clogged flue-way, or improper gas pressure.
12. Gas Burner Flame Floats
Possible Causes: Improper gas pressure, a wrong orifice, or a clogged flue.
Part 3: Noises, Odors, and Water Quality
13. T&P Relief Valve is Leaking or Discharging
The valve opens to prevent dangerously high pressure or temperature.
The Fix: If the temperature is correct, the issue is often excess pressure due to thermal expansion. If a backflow preventer, check valve, or pressure reducing valve is installed, the expanding water has nowhere to go.
Install an expansion tank on the inlet line to absorb the increased volume and prevent the relief valve from tripping.
14. Water Heater Knocking or Banging Sound
The Fix: This common noise is caused by scale buildup (sediment) at the bottom of the tank. The scale traps water pockets that boil and explode.
Try flushing the tank to remove the sediment. IMPORTANT: Turn off the gas or electricity before flushing.
15. Water Heater Sooting
Sooting indicates incomplete combustion and restricted airflow—a serious safety issue.
The Fix:
Remove any obstructions or debris from the heater or flue way.
Improve ventilation to the room.
Check for improper gas pressure or a dirty burner orifice.
An obstruction could lead to carbon monoxide poisoning. Call for professional help immediately.
16. Hot Water Smells Like Rotten Eggs 🤢
The Fix: This is caused by certain sulfur-reducing bacteria reacting with the magnesium anode rod.
Clean the tank using a chlorine bleach solution.
Change the anode rod to an aluminum type.
For older units, replacing the entire heater is often the best long-term solution.
17. Rusty or Dirty Water
Possible Causes: The anode rod has completely dissolved, or there is excessive sediment buildup.
The Fix: Check and replace the anode rod. If the rod is gone, the tank steel is actively corroding. You’re often better off replacing the unit.
18. Milky Water
The Fix: This may be harmless aerated water.
Allow a glass of hot water to sit for a few minutes. If the water turns clear, it’s a natural occurrence. If not, contact Water Heater King for help.
Part 4: Understanding the Anode Rod
19. What is an Anode Rod?
The anode rod is the single most important factor in determining the life of your water heater.
It’s made of zinc, magnesium, or aluminum and is screwed into the top of the tank.
Function: It protects the exposed steel of your tank through a process called Electrolysis, acting as a sacrificial element. The less noble metal of the anode rod corrodes before the steel tank does.
Maintenance: Manufacturers recommend inspecting the sacrificial anode every year and replacing it when it’s consumed by more than 50%. This is especially critical if you have hard water or use a water softener.
Why Choose Water Heater King, Since 1885?
We’re Water Heater King, but also PDM Plumbing, Heating, Cooling. We’ve been dedicated to the tried-and-true way of doing things since 1885. That’s the PDM difference.
When you call the experts who’ve been solving hot water problems for over a century, you get a commitment to quality:
Guaranteed Pricing: You will never be surprised by an unpleasant bill.
100% Satisfaction Guarantee: We go beyond to make you happy with our work.
Environmentally Friendly: We recycle and use sustainable materials wherever possible.
Respect: We will always clean our messes and treat your property with the utmost respect.
Have a water heater problem you can’t solve? Don’t risk a DIY mistake or a carbon monoxide leak.
Call the Experts Who’ve Been Solving Them for Over a Century!
Contact a PDM craftsman today at 815-390-7095 for water heater solutions in the greater Bolingbrook, Homer Glen, Joliet, New Lenox, Plainfield, IL area.
