Welcome Preppers and Survivalists,
You and your family need to store, at least, three days of water for everyone in the family, including pets and livestock. Two-weeks would be better.
State of Washington" Department of Health - Purifying Water During an Emergency
On the Road
Of course, we have been talking about scenarios where you and your family need to immediately leave you home. If you're walking (not recommended), you might not be able to carry enough water to get you and your family to the destination.
Backpacker - Treating Water with Bleach