How to Light Your Water Heater in 5 Easy Steps
Get your hot water heater running safely and smoothly
- Flashlight
- Long lighter
If your hot shower has turned into an uncomfortably cold one, one of the first places you should check for issues is your hot water heater. For homes with gas water heaters, you should check your pilot light to make sure it didn’t go out. Depending on the age of your heater, you may be able to relight the pilot using an ignition button or a lighter. Regardless of the age and type of water heater you have, you can use this guide on how to light a water heater to get it up and running again in just a few minutes.
Some DIY repairs are great for saving money and sharpening your skills, but leave larger jobs like water heater repair to the pros. An experienced hand can ensure the task is completed safely and will prevent further damage.
Prepping to Relight Your Water Heater
Most homeowners can relight a pilot light themselves without any issue, but it’s important to be safe when dealing with a gas water heater. You should always proceed with care when relighting a pilot light since the gas used to power your hot water heater is flammable and potentially dangerous if it builds up in your home.
If at any time you smell gas, you should shut off the gas valve right away, open windows, and avoid turning on any lights. Leave your house and call your local gas company or fire department for assistance.
Turn Off the Gas
Photo: BanksPhotos / iStock / Getty ImagesBefore you relight your pilot light, the first step is to turn off the gas. Locate the gas valve on your hot water heater and turn it to the “off” position. Wait approximately 10 minutes. This gives any gas in the area time to clear, which is important because the gas is highly flammable.
All modern gas water heaters—including nearly all tankless water heaters—include an automatic gas shut-off process that kills the flow of gas into your appliance if the pilot light goes out, so this step may not be necessary. However, it’s always a good idea to let the space air out anyway, especially if you don’t know how old your water heater is.
If you smell gas after your pilot light goes out, it likely means you have a very old water heater. It’s best to start thinking about upgrading to a tankless water heater or a new tank water heater to improve safety, efficiency, and performance.
Access the Pilot Light
The pilot light typically sits right underneath the gas valve. In some cases, there may be a door or cover over the light. Use a flashlight while completing this process to make sure you can see everything clearly.
Turn the Gas Valve to “Pilot”
Photo: knowlesgallery / Adobe StockTurn the gas valve to “pilot” and press down. This causes the gas valve to provide enough gas to light the pilot light. In some cases, your hot water heater will have a separate pilot button.
Light the Pilot
The age of your gas water heater determines how you relight the pilot. Gas water heaters made within the past eight years don’t require manual lighting. Instead, these water heaters contain an electric spark generator, much like a gas grill.
If you have a water heater with a pilot light ignition button, press the button to light the pilot light. Once the pilot light is on, keep holding it for about one minute. After letting go, make sure the flame is still there. If your water heater doesn’t have this button, you’ll need to light it manually using a long lighter.
Turn On the Gas
Photo: Vitaliy Halenov / iStock / Getty ImagesOnce the pilot light has ignited, turn the gas back on by turning the knob from “pilot” to “on” and replace the cover.
Why Is My Pilot Light Going Out?
Traditional gas heaters have their pilot lights on 24/7, whereas newer units may use an intermittent pilot light system for better energy efficiency. Some water heaters also use a hot surface igniter in lieu of a traditional pilot light.
If you notice the water isn’t hot, or that the light looks weak when it should be bright and blue, your pilot light might be going out. Below are the top reasons why that may happen:
Gas pressure: Any change in gas pressure could disturb the pilot light. This is usually fixable with a simple re-ignition. However, if the gas pressure fluctuation persists, you may need to check your external gas line.
Thermocouple/thermopile: Thermocouple powers the gas valve and shuts it down if the pilot light is out. When the thermocouple fails, the safety valve will lose its power source. In this case, your pilot light won’t stay lit once the pilot knob is released.
Drafts: Is your water heater stored outside? Strong gusts and air drafts can sometimes blow out the pilot light.
Insufficient combustible air: If there isn’t enough air, the pilot light won’t be able to stay lit. This can also lead to carbon monoxide poisoning. Therefore, always ensure enough space around the water heater for a sufficient air supply.
Residual gas: Your water heater has a safety system that prevents the pilot light from being lit if there is residual gas in the unit. To fix this, turn off the gas and let your unit sit for at least ten minutes to disperse residual gas.
Leaking, clogged, or kinked supply pipes: If something is preventing fuel from entering your unit, your pilot light may go out. Check the connecting pipes, tubes, and hoses for clogging or cracks.
Control valve failure: If you have an old water heater, the control valve might have failed. These mechanisms deteriorate over time and eventually stop working. A licensed contractor can replace the valve for around $100.
Failing ignition system: If all other methods have failed, you may have a broken ignition system. Contact a professional if you suspect the ignition system has killed the pilot light. Do not attempt to troubleshoot this yourself.
DIY vs. Hiring a Pro
You can relight a gas heater pilot light with a couple of items around your house, and it’s typically safe to do so yourself. This is especially true of newer water heater models made within the last 50 years or so, as they use a gas shut-off feature to stop the flow of gas into your home if the pilot light goes out.
However, if you’re having issues getting your pilot light to relight, ask a local water heater installation service or repair professional for help. The cost for water heater repair can vary wildly, but for a simple pilot light issue, a plumber will usually charge $50 to $150 per hour. If you have frequent issues with your pilot light or can’t get it to stay lit, call in a professional right away. For more severe underlying issues, you may need to replace your water heater.
Questions to Ask a Water Heater Pro
As always, you should shop around to find the best professional to fix your water heater. Knowing your heater’s brand, model, energy source, and year will make this process much easier. If you are ready to make calls and send out inquiries, below are some questions you should ask:
Do they have experience working with heaters that are similar in type, brand, and age to yours?
Can they provide referrals or past customer testimonials?
Do they charge an inspection fee for coming to look at your water heater?
Are they licensed and insured?
What was wrong with your water heater?
How long will the job take?
How much will the job cost?
Can they do it right now, or do they need to schedule for a later date? Can they work with your schedule if they need to come back?
Do they offer any warranties?
Dan Simms contributed to this piece.
Frequently Asked Questions
In most cases, yes, it’s safe to light a gas water heater manually, but you should shut the gas off first, open a window, and let the space air out for about 10 minutes. Modern water heaters shut the gas off entirely if the pilot light goes out, but airing out the area beforehand is good practice and will ensure it’s safe to relight your pilot light manually. Just make sure you turn the gas valve to “pilot” before lighting. If the light keeps going out or won’t light at all, call in a professional.
If your water is only lukewarm, there could be a problem with your hot water heater. It could indicate that your water heater is about to fail, there’s sediment buildup, your water heater tripped your breaker, or the temperature is set incorrectly. In some cases, your pilot light could just be out, and relighting it or calling in a water heater repair tech to fix the underlying issue should get your water back to normal. You should get in touch with a water heater repair technician to determine what the exact issue is.
The cost to repair a hot water heater ranges from $225 to $960. Costs vary depending on where you live and what’s wrong with your water heater. In some cases, you may want to replace your hot water heater instead of repairing it, especially if the appliance is 15 years old or more.
The cost to replace a water heater depends on the type you choose (tank versus tankless) and the fuel type. You can expect to pay anywhere from $880 to $1,780 for a one-to-one replacement. If you’re switching from one type or energy source to another, labor costs will rise significantly for the extra amount of work.
Some steps you can take to maintain your hot water heater include regularly inspecting your appliance and draining and flushing out the water heater to remove sediment build-up, especially if you live in an area with hard water. In addition to these DIY steps, you should also call in a professional about once a year to inspect and tune up your water heater. A pro can assess if the anode rod needs replacement, if your thermostats are working properly, and if there are any leaks that need to be addressed.
It can be an emergency if the pilot light goes out since it could lead to an accumulation of gas in your home. Most modern gas appliances and water heaters have a failsafe for this, but older models don’t. If the pilot light goes back on in the presence of a gas buildup, or there’s a spark or flame elsewhere in your home, an explosion can occur. There's likely a gas leak in your home if you notice the smell of rotten eggs and your heat or power goes out. Immediately evacuate the home, and call emergency services.
