To determine how much water a household needs for 5 days, it's often recommended to store at least 1 gallon of water per person per day for drinking and sanitation.
For a household of 2 adults and 3 children, that totals 5 people.
Calculating for 5 days: 5 people x 1 gallon per person per day x 5 days = 25 gallons
Therefore, it would be prudent to store at least 25 gallons of water to last 5 days to prepare for a disaster.
So the correct answer is 25.