Few things start a Pittsburgh morning worse than a cold shower you were not expecting. When your water heater appears to be running but no hot water reaches your taps, the cause can range from a simple tripped switch to a failed heating element or a pilot light that has gone out. Because the right fix depends entirely on whether you have an electric or gas heater, this guide is organized around both, walks you through what to check, and explains when the problem needs a licensed plumber rather than a DIY attempt.
Before anything else, identify which type of water heater you have. An electric unit connects to your breaker panel with no gas line or pilot. A gas unit has a gas supply line and a burner with a pilot light or electronic igniter. The troubleshooting paths are different for each.
First Checks for Any Water Heater
A few causes apply regardless of fuel type, so rule these out first.
- Check the thermostat setting. If someone lowered the temperature dial, water may simply not be heating enough. The typical setting is around 120 degrees.
- Consider demand. If a large household just used a lot of hot water in a short time, the tank may be temporarily depleted and need time to recover. This is normal and not a malfunction.
- Look for leaks. A leaking tank loses hot water and pressure. If you see water pooling under the unit, that is a separate problem that needs attention.
- Check the age of the unit. A heater past 10 years that suddenly cannot keep up may be failing internally.
Electric Water Heater: No Hot Water
Check the Circuit Breaker
An electric water heater draws a lot of power, and a tripped breaker is one of the most common reasons it stops heating. Go to your panel, find the breaker for the water heater, and if it has tripped, switch it fully off and then back on. If it trips again right away, stop and call an electrician or plumber, because that points to an electrical fault.
Press the High-Temperature Reset
Electric heaters have a reset button on the upper thermostat, behind an access panel on the side of the tank. If the unit overheated, this safety switch trips and cuts power to the elements. Turn off the breaker first, remove the panel, press the red reset button until it clicks, then replace the panel and restore power. If it keeps tripping, the thermostat or element is likely failing.
Failed Heating Element
Electric heaters have two heating elements. If the lower one fails you may get a small amount of warm water that quickly turns cold. If the upper one fails you may get no hot water at all. Testing and replacing an element involves working with electrical components inside the tank and is best handled by a professional who can confirm the diagnosis and replace the part safely.
Gas Water Heater: No Hot Water
Check the Pilot Light
On a gas heater, a pilot light that has gone out is the most frequent cause of no hot water. Look through the small access window near the bottom of the tank to see whether the flame is lit. If it is out, follow the relighting instructions printed on the unit, which usually involve setting the control to pilot, holding the button while you light it, and holding for the specified time before releasing.
If the pilot will not stay lit after several attempts, do not keep forcing it. A pilot that goes out repeatedly often points to a failing thermocouple or a gas supply issue, both of which need professional attention. And if you smell gas at any point, stop, leave the house, and call your gas utility and 911 from outside.
Check the Gas Supply
Confirm the gas valve to the heater is open and that other gas appliances in the home are working. If nothing gas-powered is working, the issue is with your gas supply rather than the heater itself.
Faulty Thermocouple or Igniter
The thermocouple is a safety sensor that shuts off gas if the pilot is not lit. When it fails, it can prevent the burner from staying on even when everything else is fine. Replacing a thermocouple or repairing an electronic igniter is a job for a licensed plumber familiar with gas appliances.
Tankless Water Heater: No Hot Water
If you have a tankless unit, no hot water can come from a tripped unit that needs resetting, a clogged inlet filter, mineral scale buildup from hard water, or an error code on the display. Many tankless heaters show a fault code that tells a technician exactly what is wrong. Pittsburgh’s hard water makes periodic descaling especially important for these systems, and a unit that has never been serviced may be scaled up internally.
When to Call a Plumber
You have done the safe, sensible checks. Bring in a professional when:
- The breaker or high-temperature reset keeps tripping on an electric unit.
- The pilot light will not stay lit on a gas unit.
- You suspect a failed heating element, thermocouple, or igniter.
- A tankless unit shows an error code or has not been descaled in years.
- You see leaking water, smell gas, or the unit is simply old and failing.
Our water heater services team diagnoses electric, gas, and tankless systems across Pittsburgh, makes the repair to code, and gives you a straight answer if replacement is the smarter path.
Stuck with cold water and a heater that won’t cooperate? Call Knight & Day Plumbing at (412) 887-5862. We respond 24/7 across Pittsburgh and get your hot water flowing again.
Frequently Asked Questions
Why is my water heater on but not heating?
The most common causes are a tripped breaker or high-temperature reset on electric units, a pilot light that has gone out on gas units, and a failed heating element, thermocouple, or igniter on either. A depleted tank after heavy use can also temporarily leave you without hot water.
How do I reset my water heater?
On an electric unit, turn off the breaker, remove the upper access panel, and press the red reset button on the thermostat. On a gas unit, relight the pilot using the instructions on the tank. If the reset trips again or the pilot will not stay lit, call a plumber.
Why do I only get a little hot water before it goes cold?
On an electric heater this often means the lower heating element has failed. It can also signal heavy sediment in the tank reducing capacity. Both are worth having a plumber inspect.
How Sediment and Hard Water Affect Heating
In the Pittsburgh area, hard water quietly undermines water heater performance. Minerals in the water settle as sediment on the bottom of a tank heater, directly over the burner on a gas unit or around the lower element on an electric one. That sediment acts as insulation, forcing the heater to work harder to warm the water above it and leaving you with less hot water and higher energy bills. In severe cases the buildup can cause popping and rumbling sounds as water trapped beneath the sediment boils. Flushing the tank once a year clears this out and restores heating performance, which is why a heater that suddenly seems weak is sometimes suffering from neglect rather than a failed part.
Tankless units are even more sensitive to hard water. Scale forms on the internal heat exchanger and chokes the unit’s ability to heat water on demand. A tankless heater that has lost performance and has never been descaled is almost always telling you it needs that service.
What to Expect From a Water Heater Service Call
When a plumber comes out for a no-hot-water call, the visit begins with identifying your heater type and confirming the symptom. From there the technician checks power or gas supply, tests the relevant components, and pinpoints the failed part rather than replacing things by guesswork. Many repairs, such as a thermocouple, a heating element, or a reset issue, can be completed the same day. If the diagnosis points to a tank at the end of its life, a good plumber explains the repair-versus-replace math clearly, including how a newer efficient unit can lower your bills, so the choice is yours and not a sales pitch.
Reliable Hot Water, Day or Night
For over 40 years, Knight & Day Plumbing has kept hot water running in homes across Pittsburgh, South Hills, and North Hills. Our licensed and insured plumbers service every type of water heater, offer upfront pricing with no hidden fees, and are available 24/7 for the kind of failure that always seems to happen at the worst time.
Do not settle for cold showers. Call Knight & Day Plumbing at (412) 887-5862 for fast, dependable water heater repair throughout the Pittsburgh area.