Water quantity
You should have at least 1 gallon of water, per person, per day - for drinking, food preparation, personal hygiene, and dishwashing. So, for example, if you have three family members, you should have 3 gallons a day for at least a three-day period, for a total of 9 gallons. Record the date that you bottled or stored the water on the label. Replace stored water every six months and store-bought bottled water every year.
If you have pets or a service animal, don’t forget to store water for them. Your pet needs approximately 1 ounce of water per pound (of pet) per day. If your pet is 8 pounds, you'll need a cup a day. A one-gallon jug of water, per pet, would be sufficient for a week.
Water storage
If your local water is treated commercially by a water treatment utility, you do not have to treat the water before storing it. If your water comes from a public well or other public, non-treated system, follow instructions about water storage provided by your public health agency or water provider. Likewise, if your local water comes from a private well or other private source, consult with your local public health agency about recommendations regarding storage of water. Only your local public health agency should make recommendations about whether your local water can be safely stored, for how long, and how to treat it. In all cases, it is important to change and replace stored water at least every six months.