Rheem water heaters are a common choice for American homes, and knowing how to safely raise the water temperature can improve comfort and efficiency. This guide explains when and how to increase the thermostat setting on Rheem models, differences between electric and gas units, safety considerations, and practical maintenance tips to keep your hot water at the right temperature without risking scalds or energy waste.

Understand Your Rheem Water Heater Model

Rheem offers electric and gas water heaters with different access points for adjusting temperature. Electric models typically house two thermostats behind removable panels, one for the upper element and one for the lower element. Gas models usually have a dial near the bottom burner assembly. Identifying your model and reading the user manual helps ensure you adjust the correct thermostat and stay within safe ranges.

Why Increase Temperature

There are practical reasons to raise water temperature:

Improve hot water output during high-demand periods.
Reduce risk of Legionella bacteria in certain setups, when water sits cold for extended periods (though this should be approached with caution and professional guidance).
Better performance for dishwashers or laundry that require hotter water.

However, higher temperatures increase the risk of scalding and energy use. The U.S. Department of Energy generally recommends a safe, efficient default around 120°F for most households. For households with infants, elderly residents, or immunocompromised individuals, consult a professional about appropriate adjustments.

Safety Considerations

Before changing any settings, observe these safety steps:

Turn off power to electric models at the breaker or unplug per manufacturer instructions.
Shut off the gas supply for gas models and allow the unit to cool before adjustments.
Do not exceed 140°F (60°C) to minimize scalding risk; higher temperatures raise burn hazards significantly.
Test the water temperature after adjustments using a calibrated thermometer and mixed tap practice to verify consistent results.
If the heater shows signs of damage, leaks, or uneven heating, discontinue adjustments and call a licensed technician.

How To Increase Temperature On Electric Models

Follow these steps carefully to raise the temperature on electric Rheem water heaters:

Turn off power at the circuit breaker dedicated to the water heater and confirm no electricity is reaching the unit with a tester.
Remove the access panels on the side of the tank. You may need to loosen insulation and a small screws to expose the thermostats.
Use a screwdriver to gently rotate the thermostat dial. Increase in 5-10 degree increments. Do not set above 120-130°F unless there is a specific need and you understand the risks.
Replace the insulation, secure the panels, and restore power. If your model has two thermostats, repeat the process for the second one if needed.
Run hot water at a faucet after about an hour to evaluate the new temperature. Use a thermometer to confirm the output remains within your target range.

How To Increase Temperature On Gas Models

Gas Rheem units typically use a thermostatic dial that controls the burner temperature. Proceed as follows:

Turn the thermostat dial slowly to a higher temperature setting. Common settings range from 120°F to 140°F, depending on the model.
After adjusting, turn the gas back on and monitor the flame. If the flame looks abnormally small or goes out, stop and consult a professional.
Test the hot water after 30-45 minutes to verify the new temperature. Use a mix of hot and cold water to ensure comfort and safety.

Practical Tips For Maintaining Temperature

Keep steady and safe temperatures with these practices:

Consider installing a tempering valve or anti-scald device to protect against sudden temperature spikes at taps.
Schedule periodic flushing and sediment removal to maintain efficiency, especially in areas with hard water.
Inspect the anode rod every 1-2 years to prevent tank corrosion that can affect heating performance.
Keep the area around the water heater clear and well-ventilated for gas units to maintain efficient combustion.

Troubleshooting If Temperature Won’t Rise

If you adjust the thermostat and the water temperature does not increase, consider these checks:

Thermostats may be faulty or stuck; a professional can test electrical resistance and replace components if needed.
Mineral buildup on electric heating elements can reduce heat transfer; a professional flush or element replacement may be required.
Gas models may have a failing burner, pilot, or thermocouple causing insufficient heating; this requires a licensed technician.
Check for incorrect thermostat wiring after service; miswiring can prevent heating in electric tanks.

Common Questions About Increasing Temperature

Is 120°F enough for most homes?: Yes. It provides a balance between comfort, safety, and energy use.
Can increasing temperature save energy?: Higher temperatures can raise energy use if you regularly use hot water at maximum levels; consider insulation improvements and water-saving fixtures to optimize consumption.
What about Legionella risks?: Legionella risk is typically managed through water system design and disinfection practices; raising temperature is not a substitute for proper water system maintenance.

Note: Always reference your specific Rheem model’s manual, as procedures and safety features vary by model and production year. When in doubt, contact Rheem customer support or a licensed plumber to perform adjustments safely.