How Hot Water Heaters Work

July 30, 2021 · 4 min read

Here on the Economy Plumbing Services blog we take a look at and talk about a lot about how hot water heaters can break, why they may be leaking, that sort of thing. But you know what we’ve never done? We’ve never explained how hot water heaters work. So if you’re curious how that big cylinder in your garage takes cold water and produces that relaxing, piping hot water we need!

Just about every home out there has a water heater, though they may take different shapes depending. For the part they all work the same way, at least broadly speaking. And that’s how we’re going to be talking abut it today, to keep it easily understandable. First step? Looking at the parts inside the water heater!

Parts of a Water Heater

The Tank

Inside that big cylinder is a heavy tank with a water protective liner. This holds between 40 to 60 gallons, usually. It keeps the water under 50-100 psi. The outside of the tank is covered in insulating materials to keep the heat in. Then there’s the outer shell of the heater.

The Dip Tube

The dip tube is the pipe that lets fresh water enter the water heater through the top of the tank.

The Shut-Off Valve

The shut-off valve shuts off (no duh, right?) the water flowing into the heater. The shut-off valve is outside of the tank, usually above / along the line that feeds the water into the tank.

The Heat-Out Pipe

This is the pipe that hot water travels out from the heater towards your home’s plumbing system and on to whichever appliance needs it.

The Thermostat

The thermostat in a water heater works just like the one for your home. Whatever you set it to is the temperature your water heater is going to raise the water to. Some models of water heaters will have multiple thermostats.

The Heating Element

There are two ways water heaters heat water. It could be electric or gas. Electric water heaters use a heating element, a bit of metal that gets crazy hot as electricity flows through it. Gas heaters will use a burner, igniting the gas and creating a flame to warm the tank of water.

The Drain and Pressure Relief Valves

These two valves are responsible for the maintenance and safety of the water heater. The drain valve at the bottom of the heater allows for easy access to empty the tank, as well as replace heating elements, or flush the tank of sediment. The Pressure Relief valve helps keep the pressure at safe levels.

The Sacrificial Anode Rod

This unique piece of the puzzle is suspended in the tank to help slow corrosion. It’s made of a steel core covered in either aluminum or magnesium. Basically, the corrosion will attack this rod before it does anything else – hence ‘sacrificial’.

Alright with those listed out you might already be getting a clearer idea of how it all works, but let’s lay it out here!

How it Heats the Water

Before anything else, the water heater’s thermostat is going to be set between 120 – 140° Fahrenheit. This makes it hot enough for most household uses and not too hot so as to avoid scalding etc. If you hover around the lower side of the dial, you can also save yourself some energy so be open to moving the dial if you like! With the thermostat set it’s the tank is ready to do its job.

First, the dip tube will take cold water from your freshwater lines to the bottom of the tank. At the bottom of the tank the water is warmed up via the heating element or burner until the water reaches the set temperature.

Hot water rises, so as the water heats, it moves to the top of the tank, and reaches the heat-out pipe. When an appliance draws from the water heater it will pull the hottest water first from the heat-out pipe, while the fresh cold water sinks to the bottom of the tank. When the hot water is used up, the tank will fill with cold water which will somewhat heat but instead the appliances, shower or washers, will draw warm or even cold water.

Simple thermodynamics… or something. It’s the principles of plumbing and it all works out!

So – how does your hot water heater work? Does it deliver the hot water you need to get a good shower, run a load of dishes, or laundry? If not, you know who to call!

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Oct 13, 2026

How to Respond Quickly When a Major Pipe Burst Occurs

A major pipe burst can flood your Tucson, AZ home in minutes. Stay calm, act fast, and call an emergency plumber once you've stopped the flow. How to Deal With a Major Pipe Burst, Fast Protect Your Family If you've got small children or pets nearby, get them out of the affected area right away. Either the water itself or an electrical issue could endanger them, and they won't know how to stay out of your way or keep themselves safe. Shut Off the Water Head straight to your home's main shutoff valve: don't worry about assessing the damage or grabbing any belongings yet. Turn the valve clockwise until it stops. In most homes this valve is in the basement near the water heater, by the front foundation wall, or where the main line enters from the street. Turn Off the Electricity If the burst is near any outlets, lights, or appliances, turn off power to those areas at your breaker box. Only do this if you can reach the panel safely without stepping in deep water. If it feels risky, leave it alone and wait for help. Drain Remaining Water from the Pipes With the main water supply off, open all the cold-water faucets in the house and flush the toilets once. This relieves pressure and empties the lines so there's less water to keep spraying from the burst spot. Leave the faucets open until the flow slows to a drip. Document Everything Before Cleanup Get photos and videos of the damage right after you've stopped the water. You'll want evidence of the burst pipe, your wet floors, any affected walls and furniture, and damage to any belongings. You will need this for your insurance claim later, and the insurance companies will need proof that the damage came from this burst pipe rather than something else. Move Belongings and Contain the Water Lift rugs and move electronics, furniture, and important papers out of the wet zone. If the water is spreading, roll up towels or use plastic sheeting to block doorways and keep it from reaching other rooms. Work fast but safely. Don't carry heavy, soaked items if they're too heavy for you, and focus on irreplaceable items first, like photos, electronics, and documents. Call a Tucson, AZ Emergency Plumber Don't wait if water is involved, because every minute you lose is another minute for mold to grow or a new problem to develop. A good emergency plumber can isolate the problem, make a temporary repair if it's after hours, and plan for a permanent fix as soon as possible while coordinating with a restoration team. Start Removing Standing Water While you wait for the plumber, use mops, towels, a wet/dry vacuum, or buckets to get water off the floor. The faster you remove it, the less it soaks into subfloors or walls. Open the windows and run fans to improve airflow if the weather allows. Your aim is getting the area as dry as possible. You've got this. Act fast, and call us at Economy Plumbing Service, LLC at 520-885-3510 for the best emergency plumbing service in Tucson.

Sep 03, 2026

Tankless or Traditional: What’s the Best Water Heater Option for Your Home?

The decision between tankless and traditional models for replacement water heaters in Tucson can make a real difference in your daily comfort and long-term costs. Let's take a closer look at how each type works, which will help you pick the right fit for your household. Traditional Heaters Traditional tank-style water heaters store a set amount of water, usually 40 to 80 gallons, in an insulated tank and keep it hot constantly using either gas or electricity. When you turn on the faucet, hot water flows from the tank while cold water refills it at the bottom. Tankless Heaters These heaters only give you hot water when you need it. Cold water passes through a heat exchanger inside the compact unit, and out comes hot water, nearly instantly. Pros of Both Let's consider the pros of the traditional heaters first: They're cheaper up front Installation is simpler because most homes already have the connections in place When it needs replacing, it's simple and often same-day They can handle a high flow rate (lots of usage simultaneously) The pros list for the tankless heater is also enticing: Less wasted energy from water being heated when it's not needed No running out of water, no matter how many people take showers Longer tank lifespan Takes up less space Cons of Both Here's the downsides to be aware of with traditional heaters: They use more energy (much more, in some cases) They run out of hot water, and you have to wait while they refill They're bulky and need more room for placement They need to be replaced sooner than tankless As for tankless heaters, be aware that: Installation costs are usually higher Initial purchase price is higher Flow rate is lower unless you invest in a bigger (or multiple) units Scale can form inside the heat exchanger faster than in a tank model Best Water Heaters in Tucson: Local Factors There are a few local factors that might also influence your decision. We have hard water, so that means scaling is more of an issue. Both types of heaters need to be flushed to prevent buildup, but the tankless might need it more often. We've also already got high energy bills with the hot summers we have here, so trimming that with a tankless model can make a big difference over time. Tankless water heaters pay for themselves in energy savings in about seven years, and if you take care of your model, it can last up to 20.If you're still weighing the options for your specific setup, give us a call at Economy Plumbing Service LLC here in Tucson at 520-885-3510. We're a family-owned business with more than seventeen years of honest, no-pressure service here in Tucson. We'll walk through your usage, space, and water conditions to help you choose the heater that actually fits your home and lifestyle. We also serve clients in Vail, Rita Ranch, Oro Valley, Green Valley, and surrounding areas.

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Are Your Gas Lines in Safe? Warning Signs You Can’t Ignore

We rely on our gas lines in Tucson to heat our homes, give us instant hot water, power our stoves, and more. Keeping your gas line safe is a serious responsibility, because the dangers of a problem in the gas line can be deadly. Here's some warning signs to look out for. Warning Signs That Gas Lines in Tucson Are in Trouble Emergency Signs Some warning signs are emergencies, and you cannot ignore them. Call your gas provider or emergency services and leave the area immediately if: You smell a sulfurous odor in or immediately around your house People in the house are suddenly and inexplicably experiencing headaches, dizziness, nausea, or shortness of breath If gas is escaping into the house, it can cause you and your family serious physical harm. The gas, as you breathe it, begins to displace the oxygen in your blood. You gradually asphyxiate or suffocate if you are exposed to too much for too long. Non-Emergency There are other warning signs that are less immediately serious, but you need to pay attention to them, regardless, as they could quickly turn serious: Corrosion Always inspect your pipes regularly, and if you see rust or other corrosion on them, be sure to call a qualified contractor right away. There may also be an issue if you notice flaking or bubbling of paint near your gas lines or a lot of dampness and residue around the fittings. A professional can seal joints and even replace a bad section of pipe if needed. Hissing If you hear hissing near a gas appliance or a meter, it likely means that gas is escaping. Even a little bit of a leak can increase your bills, of course, and indoors, it can create a very dangerous condition. Contact a professional contractor right away to take a look. If it's a single appliance, turn off the gas to that appliance. Bigger Bills If your habits haven't really changed, but the cost of your gas bill keeps going up, try turning off all your gas appliances and writing down the meter reading. Then, wait for an hour or two and check the meter again. If it has gone up, you have a leak. Low Pressure If the flame on your stove or in your furnace doesn't have the power it should have, then you could have a leak somewhere in the line leading to that appliance, or there could be a blockage. There also could be a faulty regulator in the appliance itself or corrosion in the piping. If several appliances seem to be affected, then the issue could be farther down the line and could be either your responsibility or something that your utility company needs to deal with. A contractor can investigate the situation and help you figure out what's going on. If you're noticing any issues with your gas line, schedule an appointment with us at Economy Plumbing Service LLC in Tucson or call us 24/7 at 520-885-3510. We also serve Vail, Rita Ranch, Oro Valley, and Green Valley.