Plastic Tank vs Steel Tank Water Heaters

Last Revised: 1/14/26

Shopping for a water heater? Beyond choosing between gas and electric, there’s another decision worth thinking about: traditional steel tanks versus the modern plastic tank models.

The advantage of each tank material is clear enough. But figuring out which one’s the better fit for your home and budget? That takes a bit more thought.

If you’re like most homeowners in Greater Philadelphia, steel tanks are what you know. So, plastic might seem a little unusual at first. But here’s the thing – both options have real benefits depending on your specific situation, your water quality, and your long-term plans.

Understanding what sets them apart can help you feel confident about your choice for years to come. Let’s walk through what you should know about plastic and steel tank water heaters.

What’s the Difference Between Plastic Tank and Steel Tank Water Heaters?

At their core, both plastic tank and steel tank water heaters do the same job: they heat and store water for your home. However, the difference in the tank’s material affects everything from durability and maintenance to costs and lifespan.

Traditional steel tank water heaters have a steel inner tank that’s coated with a glass lining to protect against rust and corrosion. They also include a sacrificial anode rod that attracts corrosive elements in the water, buying the tank more time before rust sets in. Steel tanks are the standard you’ll find in most homes, and they’ve been the go-to choice for decades.

Plastic tank water heaters (like the well-known Rheem Marathon) use a blow-molded polybutene inner tank wrapped in layers of fiberglass for strength. Since plastic doesn’t corrode, these tanks don’t need anode rods or glass linings. The result is a water heater that’s immune to rust and corrosion issues that eventually take down most steel tanks.

Durability and Lifespan: Which One Lasts Longer?

When it comes to longevity, plastic tank water heaters have a clear advantage. Because the tank itself won’t rust or corrode, manufacturers like Rheem feel confident enough to offer a lifetime warranty on the Marathon’s tank, something you might never see with steel models. Most traditional steel tank water heaters last somewhere between 8 and 12 years before rust, sediment buildup, or a failing anode rod leads to leaks and eventual replacement.

Plastic tanks have far superior longevity, but it’s important to understand what “lifetime warranty” really means. While the plastic tank itself may last decades without rusting, other components like heating elements, thermostats, and pressure relief valves still wear out over time. These parts typically need attention or replacement every 5 to 6 years, and they’re often more expensive to replace than standard water heater parts. So while the tank may outlast a steel model by many years, you’re not completely free from maintenance.

Steel tanks, on the other hand, are durable in their own right, and with proper maintenance (like flushing the tank annually and replacing the anode rod every few years), you can extend their life considerably. But eventually, rust wins. Once the tank starts leaking, repair is no longer an option, and you’ll need a full replacement.

Maintenance Requirements: What You Need to Know

One of the biggest perks of plastic tank water heaters is that they require less ongoing maintenance than steel models. You don’t have to worry about replacing anode rods or dealing with rust issues, but you’ll still need to flush the tank periodically to prevent sediment buildup. Eventually, you’ll also need to replace heating elements and other components.

Steel tank water heaters need more consistent attention. Flushing the tank once a year helps clear out sediment that can cause the tank to overheat and fail prematurely. The anode rod should be checked every 3-5 years and replaced as needed. Neglecting to maintain a healthy anode rod will shorten the water heater’s lifespan and increase the risk of water damage. The good news is that steel tank parts are widely available and relatively affordable.

Plastic tanks aren’t commonplace, so it’s important to make sure your plumber is familiar and comfortable working on them. While the technology isn’t complicated, some professionals lack experience with plastic models, and replacement parts can sometimes be more expensive or harder to find.

Performance and Efficiency: Do They Heat Water Differently?

There are two main ways that a water heater must perform: they must first heat water coming in from your cold-water supply line, and then they must keep that water hot.

And from a performance standpoint, both plastic and steel tank water heaters do a solid job of heating water.

What makes modern plastic tank models stand out, however, is their efficiency when keeping water hot. They have superior insulation, which drastically reduces standby heat loss and results in lower energy bills. Steel tanks can also be well-insulated, though they aren’t as widely renowned for it.

In terms of heating speed and hot water delivery, both types perform similarly. Your choice here will likely come down to other factors like longevity, maintenance, and cost rather than day-to-day performance.

One important thing to note: plastic tank water heaters are currently only available as electric models. If you’re looking for a gas water heater (propane or natural gas), you’ll need to go with a steel tank. For homeowners who already have electric water heating, this isn’t an issue, but if you’ve been using gas and want to switch, you’ll need to factor in the cost of electrical work during installation.

Water Quality Considerations for Greater Philadelphia Homeowners

If you live in an area with hard water, high mineral content, or water treated with chloramine (which is common in parts of the Greater Philadelphia region), a plastic tank water heater can be a game-changer. Hard water and chloramine accelerate corrosion in steel tanks, shortening their lifespan even with proper maintenance. Plastic tanks are completely immune to these issues, making them an excellent choice if your home has challenging water conditions.

That said, plastic tanks can still experience sediment buildup from minerals in the water, so regular flushing is still recommended to keep everything running smoothly.

Which One Is Right for Your Home?

Choosing between a plastic tank and a steel tank water heater comes down to your specific situation. Here’s a quick guide to help you decide:

A plastic tank water heater might be the better choice if:

• You’re planning to stay in your home for many years
• You have hard water or water treated with chloramine
• You want to minimize long-term maintenance and replacement hassles
• You’re willing to invest more upfront for long-term savings and peace of mind

A steel tank water heater might be the better choice if:

• You’re working with a tighter budget and need to keep upfront costs low
• You’re planning to move within the next several years
• You need a gas-powered model (since plastic tanks are electric-only)
• You prefer a proven, widely available product with easy-to-find parts and service

Trust Mattioni to Help You Choose the Right Water Heater

Since 1948, Mattioni has been helping homeowners throughout the Greater Philadelphia region with expert plumbing and HVAC services. When it comes to choosing and installing the right water heater for your home, experience matters.

Our team understands the unique water quality challenges in our area, and we’ll help you weigh the pros and cons of plastic and steel tank water heaters based on your home, your budget, and your long-term plans.

With a 5-star reputation built on trust, quality workmanship, and honest advice, Mattioni is here to make sure you get the right water heater that fits your needs.

Ready to upgrade your water heater? Schedule your appointment with Mattioni today.

We’ll provide expert guidance on the best water heater for your home and deliver same-day service you can count on. Whether you choose a plastic tank or a steel tank, you’ll enjoy reliable hot water, total peace of mind, and the confidence that comes from working with Greater Philadelphia’s most trusted plumbing experts.

Call Mattioni now at (610) 400-8510, because your comfort and satisfaction are our top priorities.