Water heater lifespan: what the Department of Energy says and what it leaves out

The DOE range, and how much weight it can carry

The U.S. Department of Energy’s consumer guidance on choosing a water heater says storage tank models typically last about 10 to 15 years, and tankless models about 20 years with maintenance. Most other pages repeat that figure.

The energy.gov page returned an error when we tried to open it, so the figure reached us through a search summary. A second DOE document, the Building America guideline, mentions tankless units lasting up to 20 years against 10 to 15 for tanks, though the text we extracted did not show the number. The two agree, but we still hold the range loosely, since it describes a spread across many installations and predicts nothing about yours.

A different DOE document carries another number. The Federal Energy Management Program, which advises federal buyers, models a less efficient electric storage heater with a 13-year life when it compares running costs. It is an assumption inside a purchasing comparison, so it says nothing about warranties or real lifespans, though it does fall inside the 10 to 15 year range.

What decides it in practice

Age on the serial plate costs nothing to find, and the repair or replace tool starts there. After age come two questions: what failed, and what else is wrong with the tank. A bad thermostat or element is one situation, and water on the floor under the tank is another. No Michigan source sets an age at which repair stops making sense, so we give no cutoff.

Before you phone anyone, photograph the data plate and the floor around the tank, and note any rust at the fittings, damp patches or noise when it heats. A plumber who hears the same details you saw can say far more over the phone, and the photos give you a record to compare one visit against another.

For gas heaters, the pilot is the common reason people call. DTE tells customers to contact a licensed professional if an appliance’s pilot flame goes out, and says the professional should relight it for their safety. The guide on a pilot light that will not stay lit covers the safety side.

Water heater repair describes what a repair visit involves, and water heater replacement covers the permit, the licenses and the costs we can source.

A heater near the end of that range deserves a plan before it fails, so write down the age from the serial plate and check the floor around the tank now and then. A replacement chosen on a calm Saturday is easier to price, permit and schedule than one ordered with the basement wet.

Hardness in Michigan, by utility

People expect Michigan’s water to be a special case, and utilities do report the numbers. No Michigan source links those numbers to how long a heater lasts, so read hardness as a fact about your own supply and not as a countdown.

Hardness is reported in milligrams per liter, and about 17.1 mg/L equals one grain per gallon. These are the figures from the utilities’ own 2025 reports unless noted.

• Grand Rapids: average 142 mg/L, ranging from 126 to 164, about 8.3 grains per gallon. See Grand Rapids.
• Ann Arbor: distribution average 126, range 74 to 180. The city softens its water.
• Lansing: typical 98, range 89 to 120 after treatment. The plants remove about 80 percent of the hardness.
• East Lansing: 100 to 125 as the plant water enters distribution, softened with lime.
• Saginaw: approximately 110. This line comes from the city’s 2022 report, not the latest one.
• Midland: an average of 104, which the city calls moderately hard.
• Warren: average 105, range 96 to 120, from the Northeast plant of the Great Lakes Water Authority.
• Detroit area: GLWA plants, supplying much of metro Detroit, publish ranges from 96 to 130 mg/L. Cities such as Flint and Sterling Heights print no figure in their own reports, so we use the GLWA Lake Huron plant as a stand-in, and it is no more than that.
• Kalamazoo: the city told a local radio station in 2016 that its water averages about 20 grains of hardness per gallon. That is an old news quote, not a current report.

Hardness varies inside a single system, so ask your utility for the annual water quality report that covers your address.

Standards, and what a new heater may need to be

If you are replacing an electric heater above 55 gallons, federal efficiency standards that took effect April 16, 2015 effectively require heat pump technology, according to the Department of Energy. That limits what you can buy, which is why large electric replacements often look different from the unit they replace. ENERGY STAR’s factsheet estimates a household of two saves $300 a year with a heat pump water heater compared with a standard electric tank, and larger households more. That is a national estimate, and your own bill depends on your electric rate.

Scald risk when you replace one

Whoever sets up the new heater, ask what temperature it is set to. The Consumer Product Safety Commission advises 120 degrees Fahrenheit. It says 140 degree water can burn in six seconds and 130 degree water in thirty. The Department of Energy agrees that lowering from 140 to 120 can reduce the risk of scalding, and adds that people with weakened immune systems or chronic lung conditions may prefer to stay at 140. Ask your doctor if that applies to you.

When it does go

Replacing a heater in Michigan is permit work: Sterling Heights says so on its FAQ page, and the state’s exemption list does not cover it. Whichever way you go, ask the plumber to put the permit, the removal of the old tank and the thermostat setting in writing before work starts. See do you need a permit to replace a water heater in Michigan. If you are weighing a different type, tankless versus tank compares what we can source.