Should You Repair or Replace Your Water Heater?

Start with three questions

Almost every repair-or-replace decision comes down to these:

1. Is the tank shell leaking? A rusted-through tank cannot be patched. That is a replacement, regardless of age.
2. How old is the heater? The U.S. Department of Energy says conventional storage water heaters last 10 to 15 years.
3. What does the fix cost compared with a new unit? HomeAdvisor's 2026 data puts most water heater repairs between $228 and $1,017, averaging $616, while a full replacement typically runs $882 to $1,826.

A five-year-old heater with a bad thermostat is an easy repair. A fourteen-year-old heater with a failed gas valve is a harder call, because you could pay for that valve and then face a tank failure a year later.

How can you tell how old your heater is?

Look at the rating plate on the side of the tank. Manufacturers encode the build date in the serial number, usually with letters or digits that stand for the month and year. The format differs by brand, so a quick search for your brand's serial number key, or a question to the plumber, will tell you. While you are there, note whether it is gas or electric and the tank size in gallons. Those three facts make the phone call far more useful.

Which failures are worth fixing?

Most water heater problems come from a single replaceable component. HomeAdvisor's 2026 figures for professionally installed parts give a sense of scale:

For a Denver-specific reference point, This Old House's local quotes (updated 2024) average $653 for a water heater repair and $1,887 for a water heater installation. Nearly every part on that list is a sensible fix on a heater with years left. The gas valve is the one to think twice about on an older tank. If you decide to keep the unit, a plumber offering hot water heater repair in Denver can test the part before replacing it.

Does a puddle mean the heater is finished?

Not always. Water can come from several places that are simple to fix:

• The drain valve at the bottom, which can drip if it was opened and not reseated
• The relief valve or its discharge pipe, which may be doing its job because pressure or temperature is too high
• Loose fittings on the cold inlet or hot outlet at the top
• Condensation on a gas unit, especially when very cold water first enters the tank

Dry the area, then watch where the water reappears. If it comes from under the jacket or the bottom seam with no fitting above it, the tank has failed. Never cap or plug a dripping relief valve; it protects the tank from building dangerous pressure. If the leak is in a finished basement, shut off the cold supply to the heater and turn the gas control to pilot or switch off the breaker until someone looks at it. A persistent damp spot you cannot trace may call for professional leak detection.

Does metro Denver water shorten a heater's life?

It depends on your address. Minerals settle at the bottom of a tank as sediment, which causes popping noises, slower heating and extra stress on the bottom of the tank. Hardness varies a lot across the Front Range:

• Denver Water describes its supply as soft to moderately hard. It is harder in the southern part of its system and during winter.
• Aurora Water reports an average hardness of about 136 ppm.
• Thornton reports much harder water, averaging roughly 230 mg/L, and says its plants do not remove hardness.
• Longmont reports soft water, typically 1 to 2 grains per gallon.

On a hard supply, flushing a few gallons from the drain valve on a schedule and checking the anode rod can buy real time. Homeowners in harder-water areas such as Thornton water heater service territory may also look at a softener. Ask a plumber whether adding a water softener makes sense for your hardness level rather than buying one by default.

What does replacement involve here?

Most homes go back with the same fuel and roughly the same size, which keeps the job straightforward. HomeAdvisor's 2026 figures put gas tank heaters at $700 to $2,700 installed and electric tanks at $600 to $3,500, with expansion tanks adding $90 to $350 plus labor and permits typically $25 to $300.

Permits are required in the cities that publish their rules. Denver lists water heaters in single-family homes and duplexes as quick permits through Community Planning and Development, and Thornton requires a permit to install or replace a water heater. A permitted install gets the venting, gas connection and relief valve discharge inspected, which matters in a city where about 55.5% of homes were built before 1980 and older venting is common. A new water heater installed in Denver should come with a quote that states whether the permit, the haul-away and any code updates are included.

Is this the time to switch to a different type?

A failed tank is the natural moment to consider tankless or a heat pump model, since you are paying for installation anyway. The Department of Energy says tankless units often last more than 20 years, but they cost more up front and may need a larger gas line and new venting. Heat pump water heaters need a space that stays between 40 and 90 degrees year-round, which can rule out an unheated garage in a Colorado winter. The comparison of tankless and tank heaters covers those tradeoffs in detail. If the old tank is leaking right now, a like-for-like swap is often the practical move, and you can plan a bigger change for later.

What should you ask on the service call?

A good diagnosis visit should leave you with facts, not just a price. Ask the plumber to show you the failed part or the leak location, to confirm the heater's age from the serial number, and to tell you honestly whether the tank shows rust at the fittings or the base. Ask for a repair price and a replacement price side by side, so you can weigh them against each other. If you are buying or selling a house and want the heater, venting and supply lines checked together, a broader whole-house plumbing inspection may be the better visit to book.

Quick decision guide

Gas heaters and safety

A pilot that will not stay lit is a repair issue. A smell of gas is not. If you smell gas near the heater or anywhere in the house, leave first, then call 911 and your gas utility from outside. For most of metro Denver that is Xcel Energy at 1-800-895-2999. Some towns are served by another gas company and some rural homes use propane, so check your bill. The step-by-step gas odor guide covers what to do and what not to touch.