A cold shower gets your attention, but it doesn't automatically mean you need a new water heater. A tripped breaker, failed heating element, thermostat, burner, gas control or valve can often be repaired. Here's how our licensed plumbers tell the difference — and what to consider if it is time to replace.
Signs your water heater needs attention
Hot water runs out fast or goes lukewarm
Sediment buildup, a failed element, burner or control trouble, a broken dip tube — or simply more demand than the heater can handle — can all cause it. Temperature swings can also start at a mixing valve or fixture. A plumber can test the heater instead of assuming the tank is done.
Water around the heater
A puddle might come from a loose fitting, the drain valve, the temperature-and-pressure relief valve, nearby plumbing or condensation — all usually repairable. Water leaking from the tank body itself generally means it's time to replace.
If water is actively leaking, shut off the water supply to the heater if you can do so safely, stay away from standing water near electrical equipment, and call a plumber.
Noises, smells or visible damage
Popping or rumbling often means sediment in a tank. Soot, scorch marks, damaged venting or a safety control that keeps tripping need prompt professional attention. If you smell gas, leave the house and call Dominion Energy's gas emergency line at 800-815-0083 or 911 from outside.
Rust on the outside or discolored water is worth checking but isn't proof the tank is failing — the cause could be your pipes, the water supply or minerals. Compare hot and cold taps; if only the hot water looks off, the heater may be the source.
Age and repeat repairs
The U.S. Department of Energy says tank water heaters typically last 10–15 years, and tankless units can last more than 20. Water quality, installation and maintenance make a big difference. An older unit with a leaking tank or frequent breakdowns is a stronger replacement candidate than a younger one that needs a single part.
Repair or replace? Questions to ask
Is the problem the tank itself, or a part that can be replaced?
Are the venting, gas supply, wiring, drain pan and relief valve in good condition and up to code?
How often has it failed, and are parts available?
Does it keep up with your household's busiest time of day?
What are the installed price, warranty and yearly operating cost for each option?
To compare efficiency, look at the yellow EnergyGuide label and the Uniform Energy Factor (UEF) — higher is more efficient within the same type of heater. Actual savings depend on your fuel prices and how much hot water you use.
Choosing a replacement
Tank water heaters
Size by your busiest hour, not just household size. Compare the heater's first-hour rating with how much hot water you use when showers, laundry and the dishwasher overlap. We recommend A.O. Smith for most tank replacements.
Tankless water heaters
A tankless unit heats water as it flows and won't run out — as long as demand stays within its flow and temperature-rise capacity. Sizing should account for how many fixtures run at once and the temperature of incoming water in winter. Tankless may need gas line or venting upgrades. We install Rinnai.
Heat pump (hybrid) water heaters
Hybrid models like Rheem's pull heat from the surrounding air and use far less electricity than a standard electric tank. They need enough space and airflow, a condensate drain and a spot where a quiet fan won't bother anyone. If you're replacing an electric water heater and you're a Dominion Energy South Carolina residential electric customer, you may qualify for a Dominion heat pump water heater rebate when it's installed by a licensed contractor. (The federal 25C tax credit for heat pump water heaters ended for installations after December 31, 2025.)
Safety first
Hot tap water can cause severe burns — especially for children and older adults. Don't turn up the temperature to make up for a heater that can't keep up; talk to your plumber about sizing or a mixing valve instead. Never cap a relief valve or its discharge line, and leave gas and electrical work to professionals.
Maintenance depends on your model and water. Follow the manufacturer's schedule for flushing and anode inspection — tankless units in particular benefit from regular descaling.
What a good replacement quote includes
The model and capacity, UEF, warranty, permits, any code upgrades, venting or electrical work, drain pan and relief discharge, startup testing and removal of the old heater — all spelled out, with one firm price.
Not sure whether to repair or replace? On Call's licensed plumbers have served Columbia and the Midlands since 2011. Our residential diagnostic fee is $89, waived when you go ahead with the repair, and you'll get a firm price on site. For a replacement, your plumber can walk you through financing in person. Call (803) 781-4357, request service online or learn more about our water heater services.
