All water heaters have temperature controls. Residential ones usually just say "pilot," "warm," "hot" or "very hot," as at left. Commercial ones are often marked in degrees. An example of the latter is shown at right, the box the arrow points to. The little window in front shows the temperature. The setting can be changed by unscrewing the cover, which will expose a wheel marked in degrees.

For residential controls, to determine the true temperature, it may be necessary to use a meat or candy thermometer at the tap.

By the way, we think all these devices should be set at 130. That's low enough to guard against scalding, while hot enough to prevent legionella bacteria that cause Legionnaire's disease from growing in your water heater.