I am not a food safety expert, but leaving potatoes in water for an extended period is not advisable. Potatoes can absorb water, potentially leading to changes in texture and flavor. Additionally, if the water is not changed regularly, it might become a breeding ground for bacteria. If you have concerns about the safety of the potatoes, it's recommended to discard them and use fresh ones. If you're unsure, it's always best to err on the side of caution when it comes to food safety.