The standard time to boil eggs in a water heater is approximately 10 to 12 minutes. This duration ensures that the eggs are fully cooked, with the whites firm and the yolks set but still soft. The temperature of the water in a water heater is typically around 140°F (60°C), which is sufficient to cook eggs without overcooking them. It's important to note that the size of the eggs and the starting temperature of the water can slightly affect the cooking time.

The reason for this duration lies in the heat transfer process. When eggs are placed in boiling water, the heat from the water is transferred to the eggshell, which then conducts the heat to the yolk and white. The heat causes the proteins in the egg to coagulate, leading to the solidification of the whites and the setting of the yolks. The cooking time is sufficient to achieve this without overcooking the yolks, which can become dry and unappealing.

According to the United States Department of Agriculture (USDA), eggs should be cooked to an internal temperature of 160°F (71°C) to ensure they are safe to eat. Boiling eggs in a water heater for 10 to 12 minutes typically reaches this temperature, making them safe for consumption. The USDA also recommends boiling eggs for 17 minutes if you prefer a harder-boiled egg, where the yolks are fully set and firm.

It's worth mentioning that the starting temperature of the water can impact the cooking time. If the water heater is set to a lower temperature, it may take longer for the eggs to reach the desired internal temperature. Conversely, if the water is at a higher temperature, the eggs may cook faster. However, the standard 10 to 12-minute cooking time is generally applicable for most water heaters, assuming the water temperature is around 140°F (60°C).

In conclusion, boiling eggs in a water heater for 10 to 12 minutes is an effective method to ensure they are fully cooked and safe to eat. This duration allows for even heat distribution and the proper cooking of the egg whites and yolks, as recommended by the USDA.