The amount of water you need to store depends on your specific situation and the duration of time you expect to be without access to a reliable supply. For general emergencies, experts recommend storing at least one gallon of water per person per day for drinking and basic hygiene tasks like washing hands or brushing teeth.
If you are preparing for a longer period without water, such as during a natural disaster or extended power outage, it is advisable to increase your storage. For example, the Federal Emergency Management Agency (FEMA) suggests storing at least three days worth of water supply. This means that if you have a family of four, you should aim to store at least twelve gallons for those first seventy two hours.
For longer periods beyond three days, you may need even more storage capacity. It is important to consider how much water your household uses daily and plan accordingly. You can find additional resources on the FEMA website: https://www.fema.gov