If you turn on the shower and nothing but icy water comes out, you’re not alone. Every winter in Hamilton, dozens of homeowners face the same frustrating problem: no hot water. It’s not always a broken water heater. Sometimes it’s something simple you can fix yourself. Other times, it’s a sign your unit is done for. The most common cause of no hot water? A pilot light that went out.
Pilot Light Out - The #1 Culprit
Gas water heaters rely on a small, continuous flame - the pilot light - to ignite the main burner when heat is needed. If that flame goes out, the heater can’t produce hot water, even if everything else works. It’s not rare. In fact, over 60% of gas water heater calls we get in Hamilton during fall and winter are because the pilot light went out.
Why does it happen? Drafts from open windows or vents, a weak thermocouple, or even a sudden drop in gas pressure can snuff it out. Older units are more sensitive. If you hear a faint hiss but no flame when you look in the inspection window, that’s your clue.
Reigniting it is easy. Turn the gas valve to "Off," wait five minutes for gas to clear, then follow the instructions printed on the tank. Usually, you hold the pilot button down, press the igniter, and keep holding for 30 seconds after the flame catches. If it won’t stay lit after two tries, the thermocouple is likely faulty.
Thermocouple Failure - The Silent Killer
The thermocouple is a tiny metal rod next to the pilot light. It senses whether the flame is on. If it doesn’t feel heat, it shuts off the gas supply as a safety feature. Over time, it gets coated in soot or wears out. A bad thermocouple is the #2 reason pilots won’t stay lit.
You can test it with a multimeter, but most people don’t have one. Here’s the shortcut: if the pilot lights but goes out as soon as you let go of the button, the thermocouple is the problem. Replacing it costs under $20 and takes 20 minutes. You don’t need to drain the tank. Just shut off the gas, disconnect the old one, and screw in the new. Make sure the tip sits right in the flame.
Sediment Buildup - The Slow Death
If your water heater is over 8 years old and you’ve never flushed it, sediment is probably the hidden villain. Hard water in Ontario leaves behind minerals like calcium and magnesium. They sink to the bottom of the tank and form a thick layer. This layer acts like insulation. The burner heats the sediment instead of the water.
Result? You get lukewarm water for a few minutes, then it runs out. Or worse - the tank overheats, causing the pressure valve to leak or the bottom element to burn out. You might hear popping or rumbling noises before the hot water disappears entirely.
Flushing the tank once a year prevents this. Turn off the power or gas, close the cold water inlet, attach a hose to the drain valve, and open it. Let it run until the water comes out clear. It’s messy, but it adds 5-10 years to your heater’s life. Skip this, and you’re paying for a new unit sooner than you think.
Thermostat Problems - Not Always the Culprit
People blame the thermostat first. But electric water heaters have two thermostats - upper and lower - and both have to work. If the upper one fails, you get no hot water at all. If the lower one fails, you get a small amount of hot water before it runs cold.
But here’s the catch: thermostats rarely fail on their own. More often, the problem is a tripped high-limit switch or a bad heating element. If you’ve got an electric heater and no hot water, check the reset button on the upper thermostat. It’s a small red button. Push it. If it clicks, that was your issue.
If it doesn’t click, or if it clicks but you still have no hot water, you need to test the elements. A multimeter will tell you if they’re dead. If both are good, then the thermostat might be faulty. But don’t assume - test first.
Power or Gas Supply Issues
It sounds obvious, but people forget. Is the circuit breaker for your water heater tripped? Did the gas company shut off service? Did someone accidentally turn the gas valve to "Off" while cleaning under the unit?
For electric heaters, check the breaker panel. Look for the 30-amp double-pole breaker labeled "Water Heater." Flip it off and back on. If it trips again, there’s a short - call a pro.
For gas heaters, check the main gas shutoff near the meter. Is it open? Is the valve on the heater itself in the "On" position? Sometimes, a new tenant doesn’t know how the system works. A quick check takes 10 seconds and saves a service call.
Age and Wear - The Final Answer
If your water heater is 12+ years old, and none of the above fixes work, it’s likely time to replace it. Most units last 8-12 years. After that, corrosion eats away at the tank lining. Even if the burner and thermostat are fine, the tank itself can develop tiny leaks or lose efficiency.
Signs it’s done: rust on the pipes near the top, water pooling under the tank, or strange smells coming from the hot water. If you’ve had to fix it more than twice in the last two years, replacement is cheaper than continued repairs.
Modern tankless heaters are more efficient, but they cost more upfront. A new 40-50 gallon tank heater with a 10-year warranty runs $800-$1,200 installed in Ontario. It’s a big expense, but it’s better than waking up to cold showers in December.
Quick Checklist: What to Do First
- Is it gas? Check if the pilot light is on. If not, relight it.
- If the pilot won’t stay lit, the thermocouple is likely bad.
- Is it electric? Press the red reset button on the upper thermostat.
- Check the breaker or gas valve - simple fixes, often missed.
- Is the water heater over 8 years old? Flush it now - it might fix everything.
- Any rust, leaks, or strange noises? Time to replace it.
When to Call a Pro
You can handle pilot lights, thermocouples, and flushing yourself. But if you smell gas, hear hissing from the tank, or see water leaking from the bottom, turn off the gas or power and call a licensed technician immediately. Gas leaks are dangerous. Water pooling under the tank can rot your floor.
Also, if you’re not comfortable using a multimeter or working with gas lines, don’t guess. A $120 service call is cheaper than a flooded basement.
Why do I only get a little hot water before it turns cold?
This usually means the lower heating element in an electric water heater has failed, or sediment has built up at the bottom of the tank. The upper element heats the top portion of water, but the lower one can’t reach the rest. Flushing the tank or replacing the element fixes it.
Can a broken dip tube cause no hot water?
Yes, but rarely. The dip tube sends cold water to the bottom of the tank. If it breaks, cold water mixes with hot water near the top, making the output lukewarm. You’ll notice white plastic flakes in your faucet screens. Replacing it requires draining the tank - it’s doable, but most people replace the whole unit instead.
Does turning up the thermostat fix no hot water?
Only if the thermostat was set too low. Most water heaters are preset to 120°F - that’s safe and efficient. Turning it higher won’t fix a broken element, pilot light, or sediment buildup. In fact, setting it above 140°F increases scald risk and energy bills.
Why does my water smell like rotten eggs?
That’s sulfur bacteria reacting with magnesium anode rods in the tank. It’s not dangerous, but it’s gross. Flushing the tank with hydrogen peroxide kills the bacteria. Replacing the magnesium rod with an aluminum one stops it from coming back.
Should I replace my water heater before it fails?
If your unit is over 10 years old and you’ve had repairs, yes. Waiting for it to leak can flood your basement, ruin drywall, and cost thousands. A new unit costs less than emergency repairs plus water damage cleanup. Plus, modern heaters are 20-30% more efficient.
Next Steps
Start with the easiest fixes: check the pilot light, reset the breaker, press the thermostat button. If that doesn’t work, flush the tank. If you’re still stuck, take a photo of the model number and call a local pro. Most service companies in Hamilton offer same-day appointments for no hot water - it’s one of the most common calls they get.
Don’t wait for a cold shower to become a crisis. A few minutes of checking now can save you hours of discomfort - and a big repair bill later.
