The length of time you can leave a pot of water on the stove depends on several factors, such as the stove's heat setting, the amount of water in the pot, and the type of pot you are using. Here are some general guidelines:
Boiling water: If you are boiling water on high heat, it will typically reach its boiling point (212°F or 100°C) within a few minutes. Once it starts boiling, you can turn down the heat to a simmer to keep it hot without the risk of it boiling over. It's generally safe to leave the water simmering for an extended period, but keep an eye on it and add more water if necessary to prevent it from drying out.
Simmering or Low Heat: If you have the water on a low heat setting, such as simmering, it's safe to leave it on the stove for a longer period. Just make sure there is enough water in the pot to avoid it drying out completely.
Medium Heat: Leaving water on medium heat can be done for a while, but it's best to attend to it regularly to avoid any issues like overheating or boiling over.
Unattended Stove: It's essential to be cautious about leaving any cooking unattended for extended periods, as accidents can happen. If you need to leave the kitchen while the stove is on, consider turning off the stove or setting a timer to remind you to check on it.
Keep in mind that if the pot is completely dry, it can cause damage to the pot and potentially create a fire hazard. It's always best to practice caution and not leave the stove unattended for too long, especially if there's a chance the water could boil off entirely.
If you need hot water for various purposes but don't want to leave the stove on, an electric kettle or a thermal carafe can be useful alternatives to keep water hot for an extended period.