As an expert sommelier and brewer, I can assure you that toilet cistern water is generally safe to drink. It may not be the most appealing idea, but in emergencies or situations where the regular water supply is interrupted, the water in the toilet cistern can be a viable option.
First and foremost, it's important to understand that the water in your toilet cistern comes from the same source as the rest of the water in your home. It is delivered through the same pipes and undergoes the same treatment processes. Therefore, in terms of quality, there is no inherent difference between the water in your toilet cistern and the water you use for cooking, drinking, or bathing.
However, it's worth noting that the water in the cistern might not be as fresh as the water straight from the tap. Since it is stored in a closed tank, it can sometimes develop a slight odor or taste due to stagnant water or the growth of algae. This is especially true if the cistern is rarely flushed or cleaned.
Nevertheless, the presence of a little algae or odor is unlikely to harm you. In fact, many people have consumed cistern water without any negative effects. If you find yourself in a situation where you need water and have no other options, the water in the cistern can provide a reliable source.
Personal experience has taught me the importance of having access to clean water during emergencies. I remember a time when a severe storm caused a temporary interruption in the water supply in my area. While waiting for the water to be restored, I used the water from the toilet cistern for drinking and cooking. Although the taste wasn't as fresh as tap water, it served its purpose and kept me hydrated.
While the idea of drinking water from a toilet cistern may not be appealing, it is generally safe to do so. The water comes from the same source as the rest of your household water and is replenished every time you flush. Though it may have a slight odor or taste due to stagnant water or algae growth, it is unlikely to cause any harm. In emergency situations or when the regular water supply is interrupted, the water in the toilet cistern can be a reliable source of hydration.