Why Your Water Heater Keeps Running Out of Hot Water

If showers used to last and now go cold halfway through, something changed. Water heaters rarely lose capacity for no reason, and the cause is often a repair rather than a new heater. Here are the usual suspects we find in homes around Carmel, Fishers, Westfield and Indianapolis.

Sediment taking up space

Hard water is the rule across Hamilton County. Every time the tank heats, minerals settle to the bottom and build up a layer of scale. That layer takes up room, insulates the water from the burner or lower element, and slows recovery.

Signs: popping or rumbling while the heater runs, less hot water than before, and sometimes gritty bits in faucet aerators.

Fix: a flush, and on electric units a check of the lower element, which often gets buried in scale. A water softener keeps it from coming back as fast.

A failed heating element (electric heaters)

Most electric tanks have an upper and a lower element. When the lower one fails, only the top part of the tank gets heated, so you get a short burst of hot water and then lukewarm. When the upper one fails, you may get no hot water at all.

Fix: we test both elements and their thermostats and replace the bad part. On a heater that is otherwise in good shape, this is a common, worthwhile repair.

A thermostat that is off

A thermostat can fail, drift or simply be set too low. Some homeowners turn the dial down to save energy and forget. On gas units the thermostat is part of the gas control valve on the front.

Fix: check the setting first. Around 120 degrees works for most homes. If it is set right and the water still is not getting hot, the thermostat or valve may need testing.

A broken dip tube

The dip tube carries incoming cold water to the bottom of the tank. If it cracks or breaks off, cold water mixes in at the top where the hot water leaves, and the shower cools off quickly even though the tank is full of heat.

Signs: hot water that turns lukewarm fast, sometimes with small bits of white plastic in aerators or showerheads.

Fix: replace the dip tube and clean out the debris.

Burner problems (gas heaters)

A dirty burner, weak flame or a pilot that keeps going out means the tank never fully heats. Blocked air openings at the bottom of the heater and poor venting can also affect the flame.

Fix: clean and adjust the burner, check the thermocouple and venting, and confirm safe combustion. If you ever smell gas, leave the house and call your gas utility or 911.

The heater is too small for how you live now

If the heater has always come up short, or you have added people, a bathroom or a big soaking tub, it may be undersized. A finished basement bathroom in a Fishers or Westfield home is a common example. Colder incoming water in winter also means any heater delivers a little less hot water in January than in July.

Fix: step up a tank size, or consider a Navien tankless unit sized to run more than one fixture at a time. Spreading laundry and dishwashing away from shower time helps in the meantime.

Repair or replace?

On a heater under about 8 to 10 years old, the issues above are usually repairs, and we recommend fixing it. Replacement becomes the better value when the tank is older and rusting, leaking at the base, or needing one repair after another. If that is where you are, we will explain why and give you options, including Bradford White tanks and Navien tankless.

When to call us

If you are running out of hot water and a thermostat check did not help, call or text us. Your plumber will test the elements or burner, check the dip tube and sediment, and give you options and a price before any work starts. Learn more on our water heater repair and replacement page.

FAQ

Why does my shower go cold after only a few minutes?

On an electric heater, a failed lower element is the most common cause. A broken dip tube can do the same on gas or electric. Both are repairs.

Is it normal to have less hot water in winter?

A little, yes. Incoming water is much colder in winter, so the heater has more work to do. A big drop compared to last winter points to sediment or a failing part.

Will flushing the tank fix it?

If sediment is the problem, flushing often helps a lot. If a part has failed, flushing alone will not fix it. On older tanks that have never been flushed, have a plumber do it the first time.

Can I just turn the temperature up?

Raising it slightly can stretch your hot water, but it adds scalding risk and speeds up scale. A mixing valve on the heater is a safer way to get more usable hot water from a tank.

Would tankless solve the problem for good?

A properly sized tankless unit will not run out, but it has a flow limit, so it has to be sized for how many fixtures you run at once. In hard water it also needs regular descaling.

Tired of cold showers? Call or text (317) 731-3028, or request service online.