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!

If Water Runs Through it Or To It, We Do It!

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 more 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 more 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.

Jul 15, 2026

Signs Your Home Needs Repiping: When Tucson Homeowners Should Replace Old Pipes

Most homeowners do not think about their plumbing pipes until there is a major leak or a sudden drop in water pressure. However, aging pipes can create ongoing problems that repairs may only temporarily fix. If your Tucson home has older plumbing, whole house repiping may be the right solution to improve reliability and prevent future damage. Economy Plumbing Service, LLC helps homeowners identify when their plumbing system needs more than another repair. Knowing the warning signs can help you address problems before they become expensive emergencies. more What Is Whole House Repiping? Whole house repiping involves replacing old or damaged plumbing pipes throughout a home. Instead of repairing one failing section at a time, repiping replaces aging pipes with new plumbing materials designed to provide better water flow and long-term performance. Many older Tucson homes still have original plumbing systems that may be affected by corrosion, mineral buildup, and years of use. Signs Your Home May Need Repiping Frequent Pipe Leaks If you are regularly dealing with leaking pipes or repeated plumbing repairs, the problem may be the age and condition of your entire plumbing system. Multiple leaks in different areas of your home often indicate that the pipes are reaching the end of their lifespan. Low Water Pressure Low water pressure throughout your home can be a sign of restricted or deteriorating pipes. Mineral buildup from Arizona’s hard water can collect inside plumbing lines over time, reducing water flow and making faucets and fixtures less effective. Discolored Water Brown, rusty, or cloudy water may indicate corrosion inside older pipes. While occasional discoloration can happen for several reasons, ongoing issues should be inspected by a professional plumber. Noisy Pipes Banging, knocking, or rattling pipes can point to underlying plumbing problems. While some noises are minor, consistent sounds may indicate aging pipes or pressure issues that require attention. Older Plumbing System The age of your home is an important factor when considering repiping. Many older homes in Tucson have plumbing materials that can become more vulnerable to leaks, corrosion, and reduced performance over time. Why Tucson Homes Can Have Unique Plumbing Issues Arizona plumbing systems often deal with hard water, which can contribute to mineral buildup inside pipes. Over years, this buildup can restrict water flow and place additional strain on your plumbing system. For older Tucson homes, replacing outdated pipes can help improve water pressure, reduce repairs, and provide a more dependable plumbing system. Is Repiping Better Than Constant Repairs? If you are frequently repairing leaks or dealing with ongoing plumbing problems, replacing your pipes may be more cost-effective than continuing temporary fixes. A complete repipe can provide: Improved water pressure Fewer plumbing repairs Reduced risk of leaks More reliable water delivery Schedule a Repiping Inspection in Tucson, AZ If your home has frequent leaks, low water pressure, or aging pipes, Economy Plumbing Service, LLC can help determine whether repiping is the right option. Our Tucson plumbing team provides professional repiping services and whole house pipe replacement to help homeowners protect their homes and improve their plumbing systems. Contact Economy Plumbing Service, LLC today to schedule a plumbing inspection and find out if your Tucson home needs repiping.