If your water heater is leaking, act in this order. Shut off the cold water valve above the heater. Turn the gas control to "pilot" or "off", or switch off the breaker for an electric heater. Then limit the water damage and find where the leak starts. Many leaks are repairable. A leak from the tank itself is not.
This guide takes you through each step, then helps you figure out what you are looking at. We are Tyler and Cam, the two owners of The Water Heater Bros. We repair and replace water heaters across the Phoenix Valley, and we do the work ourselves. Here is what we would tell you if you called us with a puddle in the garage.
Step 1: Stop the Water and Make the Heater Safe
If you see water around your heater, the first goal is to stop more water from coming in. The second is to make sure the heater is not heating with a problem. Both take only a few minutes.
Shut off the cold water supply
Look at the pipes on top of the heater. One is the cold water inlet, and it should have a shutoff valve on it. Turn a round handle clockwise until it stops. Turn a lever handle so it sits across the pipe. This stops new water from entering the tank.
If you cannot find that valve, or it will not turn, shut off the main water to the house. In many Phoenix homes the main shutoff sits near where the water line enters, often by the garage or front of the house.
Turn off the heat source
- Gas heater: turn the gas control knob to "pilot" or "off"
- Gas heater, strong gas smell: leave the house and call your gas utility from outside
- Electric heater: switch off the heater's breaker at the electrical panel
- Tankless heater: turn off its power and close its gas valve if it has one
Turning off an electric heater matters more than people think. If the tank drains while the power is on, the heating elements can burn out in seconds. That turns a leak into two repairs.
Stay safe around the water
The water in the tank and on the floor may be very hot. Give it time to cool before you touch fittings. Keep kids and pets away. If water is near outlets, cords or the panel, keep clear and shut off power to that area first.
Step 2: Limit the Damage
Once the water is off, focus on keeping the leak from spreading. Where your heater sits makes a big difference. Many Phoenix heaters are in the garage, where a leak is messy but easy to manage. Heaters in an interior closet or an attic can soak drywall, flooring and ceilings.
Quick ways to contain the water
- Move boxes, rugs and anything stored near the heater
- Soak up standing water with towels or a wet vac
- Set a bucket or shallow pan under an active drip
- Check that the drain pan under the heater is draining, if you have one
- Take photos of the leak and any damage for your records
Should you drain the tank?
Draining the tank stops the leak for good, because there is no water left to push out. It also lowers the risk if the tank is badly rusted. But it takes some care. Only drain once the water has cooled and the heat source is off.
To drain the tank:
- Connect a garden hose to the drain valve near the bottom of the tank.
- Run the hose outside, or to a floor drain that sits lower than the valve.
- Open a hot water tap in the house to let air in.
- Open the drain valve slowly.
If the drain valve is the part that is leaking, or it is plastic and brittle, skip this step. Forcing an old valve can make the leak worse. In that case, keep the water shut off and wait for a pro.
Step 3: Find Where the Leak Is Coming From
If the water is off and the area is safe, you can start looking for the source. Dry the outside of the heater with a towel and use a flashlight. Water runs downhill, so a puddle on the floor does not always mean the leak starts at the bottom. Work from the top down.
The most common leak sources
- Pipe fittings on top. Drips at the cold inlet, hot outlet or shutoff valve.
- T&P valve or its pipe. Water coming out of the side pipe that runs toward the floor.
- Drain valve. A drip from the spigot near the bottom of the tank.
- Tank bottom or seams. Water seeping from under the jacket with no other source.
- Condensation. Beads of water on a cold tank, usually after a big hot water draw.
- Something nearby. A softener, AC drain line or pipe close to the heater.
What the T&P valve is telling you
The T&P valve is the temperature and pressure relief valve. It is a safety valve on the side or top of the tank. It opens to let water out if pressure or temperature inside the tank gets too high. Water from its discharge pipe means one of two things. The valve may be worn and leaking, or it may be doing its job.
If it is doing its job, the real problem is high pressure or an overheating heater. A common cause is thermal expansion. Water grows as it heats, and a closed plumbing system gives it no room. An expansion tank adds that room. Never cap or plug a T&P valve. It is there to keep the tank from failing.
A leak from the tank itself
If water is coming from the bottom of the tank and you cannot find any other source, the tank has most likely failed. Rust has eaten through the steel from the inside. This is common in older heaters, especially where Phoenix hard water and a worn-out anode rod have done their work over the years.
Is the Leak Repairable, or Is It Time to Replace?
If you are hoping this is a simple fix, there is a good chance it is. Many heaters do not need replacing when they act up. Sometimes a simple repair is the better choice, and we will tell you so. The source of the leak decides most of it.
Leaks that are usually repairable
- Loose or corroded fittings on the inlet or outlet pipes
- A worn or leaking shutoff valve
- A worn T&P valve that drips when pressure is normal
- High pressure that an expansion tank can solve
- A leaking or broken drain valve
- A loose connection on a tankless heater's water lines
Leaks that usually mean replacement
- Water seeping from the bottom of the tank or its seams
- Rust stains on the tank body with active leaking
- Rusty hot water along with a leak at the base
A tank leak cannot be patched in any lasting way. The steel is rusting through from the inside, and more weak spots usually follow. At that point, replacing the heater is the safe choice. For a closer look at what that involves, see our water heater replacement services page.
Age matters too. If your tank heater is 10 or more years old, even a repairable leak is worth a talk. We can lay out both options clearly so you can decide without pressure. Most standard installs take 2–4 hours once you choose.
What a Leak Repair or Replacement Costs
If you are worried about cost, start with the good news. A quote by phone, call or text, is free. Send us a photo of the heater, its label and where the water is coming from. That often tells us a lot before we ever arrive. We give clear pricing before any work starts.
What changes the price of a leaking heater:
- Leak source. A fitting or valve swap is a smaller job than a new heater.
- Heater type. Tank, tankless and heat pump heaters each need different parts.
- Size and fuel. A larger tank or a gas-to-electric change adds parts and time.
- Location. Attic and tight closet installs take longer than an open garage.
- Code updates. An expansion tank, drain pan or venting fix may be needed.
- Permits. The city may require a permit; we will tell you if yours does.
Our prices tend to be low because we bulk-order heaters and parts from a small group of manufacturers. We also carry only the tools water heater work needs. Less overhead lets us pass savings on to you. Installs come with the manufacturer warranty, and we stand behind our workmanship.
Watch out for pressure to replace
A leak is stressful, and that is when some homeowners get pushed into a new heater they may not need. A dripping valve does not mean a dead tank. Ask what exactly is leaking and why. We work with zero sales pressure and will show you what we found.
When to Call a Pro, and What to Do After Hours
Some leak steps are fine for a homeowner. Others carry real risk from gas, electricity, scalding water or pressure. Here is where we draw the line.
Fine to do yourself
- Shut off the cold water and the gas or power
- Contain water and protect your belongings
- Drain a cooled tank through a working drain valve
- Snug a visibly loose fitting a quarter turn, if it is easy to reach
Call a licensed pro for
- Any work on gas lines, gas valves or venting
- Replacing a T&P valve, drain valve or shutoff valve
- Installing an expansion tank
- Any leak from the tank body
- Leaks in an attic or ceiling space
- Tankless heater leaks inside the cabinet
You can read more about common fixes on our water heater repair services page. City homeowners can also see our page on water heater repair in Phoenix.
Our hours, honestly
We work Mon–Sat, 8 AM to 5 PM, Arizona time. We are closed Sunday. We are not open around the clock, and we will not pretend to be. If your heater starts leaking outside those hours, follow the steps above to make it safe. With the water and the heat source off, most leaks will hold until morning.
Then call or text us. Send a photo of the heater and the leak if you can. We reply when we open and set up a time to come out.
How to Lower the Odds of Another Leak
Once your leak is fixed, a little yearly care helps prevent the next one. Hard water in the Phoenix Valley is the main reason tanks rust and valves wear out early. Most leaks we see trace back to buildup, worn parts or pressure that went unchecked.
- Flush a tank heater once a year to clear sediment
- Descale a tankless heater once a year to clear scale
- Check the anode rod so the tank does not rust from inside
- Consider a powered anode rod that does not wear away
- Add an expansion tank if your plumbing system is closed
- Look at the heater monthly for drips or rust at the base
Our guide on protecting your water heater from Phoenix hard water goes deeper into each of these. If you just want a second set of eyes, book a free water heater inspection. There is no pressure and no obligation. We will tell you how to repair, improve or extend your heater's life.
Need a Water Heater Specialist in Phoenix? The Water Heater Bros Are Ready to Help
A leaking water heater is stressful, but the right first steps keep the damage small. Shut off the water, turn off the heat, contain the mess and find the source. Then let us help you decide between a repair and a replacement, honestly.
Tyler and Cam do every job themselves and are licensed under AZ ROC 363269. We work Mon–Sat, 8 AM to 5 PM, Arizona time. Call or text (602) 901-6418 or contact us to book a time. From our family to yours, honest repairs and dependable service.