Exploring the Temperature of Dishwasher Water


Dishwashers are known for their use of heated water to effectively clean dishes. But have you ever wondered how hot the water actually gets? In this article, we will delve into the temperature range of dishwasher water, how dishwashers heat the water, and the role of heated water in the drying process.

Understanding the Temperature Range

When it comes to dishwasher water temperature, the exact range can vary depending on the model and wash cycle. On average, dishwashers heat water to a temperature of 120 to 140°F (49 to 60°C). Some models even go beyond and reach temperatures of 150°F (66°C) or higher to enhance sanitization. The specific temperature settings are determined by the selected wash program.

Time Taken to Heat Water

Typically, dishwashers spend approximately 1 to 2 minutes to heat up the water. During this time, the heating coil gradually reaches its maximum temperature, causing a slight delay in the process. If you notice a prolonged delay between water filling and spraying, it may indicate a heating issue that requires professional attention.

The Heating Mechanism

Located at the bottom of the dishwasher tub, there is a heating coil that wraps around the base’s entire perimeter. This coil is connected to a heat motor. When you activate the dishwasher, the heat coils increase to a specific temperature based on the wash cycle, heating the incoming water. While it’s not necessary to connect your dishwasher to the hot water supply line, doing so can reduce the time required for the coils to heat the water.

Dishwashers are equipped with thermostats to measure the water temperature. The dishwasher proceeds to the next phase, which is washing, only when the water reaches a predetermined temperature based on the selected wash program. Connecting your dishwasher to a neutral temperature line is possible, but it will result in the coils requiring more time to raise the water temperature.

Drying Process

Once the wash and rinse cycles are complete, dishwashers move on to the drying phase. Different dishwashers employ various heating methods for drying purposes. In older models, heating coils would warm the air inside the tub. A built-in fan would circulate the heated air, causing water droplets on the dishes to evaporate over time.

Modern dishwashers, however, do not rely on fans or activated heating coils for drying. Instead, the residual heat from the rinse and sanitize cycles causes moisture droplets on the dishes to drip down into the tub, facilitating drying.

The Role of Rinse Aid

Rinse aid, available in liquid form, acts as a drying agent in dishwashers. It is placed in the rinse aid compartment of the dishwasher and sprayed onto the dishes during the cycle. Rinse aid possesses slight hydrophobic properties, causing the coated dishes to repel water. As a result, water droplets have a harder time adhering to the dishes and tend to slide off, leading to quicker drying. However, it’s important to note that rinse aid does not eliminate water pooling in items such as bowls, pots, and pans.

Cold Water Usage

Dishwashers do utilize cold water in certain wash programs. For example, an Express Rinse program uses the water available at its current temperature without heating it further. In this case, the heating coils remain inactive, regardless of the initial water temperature. However, heated dry and sanitize wash programs require hot water. The dishwasher’s control board monitors the water temperature through the thermostat. If the coils fail to raise the water temperature within the required range, the dishwasher will not initiate the heated dry or sanitize wash program.

Potential Issues with Excessive Water Temperature

While dishwashers themselves are designed to prevent water from reaching excessively high temperatures, external factors can affect the effectiveness of the detergent and potentially cause damage. For instance, if the water heater in your home is set above 150°F (66°C), the super-heated water may interfere with the detergent’s performance, leading to suboptimal cleaning results. Furthermore, excessive water temperature can cause damage to the dishwasher’s interior, particularly plastic components such as the cutlery basket and dish racks.

To avoid such issues, it’s advisable to check and adjust your water heater’s temperature during dishwasher setup. Ideally, the water temperature should be set between 110 and 130°F (43 to 54°C). To determine the temperature accurately, run the hot water faucet for 15 seconds and use a thermometer to measure the temperature manually.

Excessively hot water can also contribute to limescale accumulation inside the dishwasher. Limescale, caused by calcium carbonate deposits, is more common in areas with hard water. Over time, the buildup of calcium ions forms solid deposits, leaving a chalky residue that can hinder the dishwasher’s performance.

Consequences of Insufficiently Hot Water

If the water in your dishwasher is not hot enough, it may fail to activate the cleaning properties ofthe detergent effectively. Insufficiently hot water can result in inadequate removal of food particles, stains, and bacteria from the dishes, compromising the cleanliness and hygiene of your utensils.


Dishwashers heat water to temperatures ranging from 120 to 140°F (49 to 60°C), with some models reaching even higher temperatures for enhanced sanitization. The heating coil and thermostat work together to raise the water temperature to the desired level. The residual heat from the wash and rinse cycles aids in drying dishes, while rinse aid can further enhance the drying process. It’s important to maintain an appropriate water temperature to ensure optimal cleaning and avoid any potential issues caused by excessively hot or cold water.