Emergency water & power planner for small homes
Calculate a household emergency water target, storage-container shortfall and essential backup-power budget. Print a practical free plan.
Plan for a water outage and a power outage together. Start with the CDC minimum of 1 gallon per person per day for at least 3 days and try for 14 days when space permits. Pets, heat and individual health needs may require additional water; enter an extra amount that suits your household.
Your water + power plan
Next actions
- Confirm safe drinking-water sources and food-grade storage containers.
- Choose cool, dark, stable storage space appropriate to the total weight; avoid overloaded shelves and balconies.
- Label self-filled water and rotate it every six months; follow the expiry date for commercial bottled water.
- Measure real running power and check any portable battery's output/connector compatibility.
- Print the plan and keep a copy where your household can find it during an outage.
This scenario is an estimate, not an emergency guarantee. Water with chemicals/fuel cannot be made safe by boiling or routine household disinfection.
What the calculator assumes
The CDC baseline is one US gallon (3.785 liters) per person per day; the 3-day and 14-day goals are preparedness targets, not a promise that a specific household has enough for every need. Extra water for hot weather, illness, pregnancy or pets must be considered separately. The calculator never silently assumes those needs are zero—it shows additional fields for you to complete.
Stored gallons are counted only when you confirm they are safe water. It does not treat a rain barrel, household tub or suspect supply as potable. Water weighs approximately 8.34 lb per US gallon before the container; secure storage must account for that load. Do not infer structural safety from this calculator.
Essential energy is operating watts × hours per day. Required nominal battery Wh is daily Wh × outage days divided by the assumed delivery fraction; this intentionally excludes charging, additional inverter standby and held-back charge. Use separate manufacturer information for those boundaries.
Free companion resources
- Emergency water storage in apartments and small homes
- Printable water rotation and inspection checklist
- Blackout essentials and priority-load checklist
Want a complete printable plan?
The upcoming 11-page Emergency Water & Power Planning Kit has a storage layout, water rotation log, essential-device worksheet, battery comparison and 30-day action plan. The intended price is $19 once, with no subscription. The paid download is not yet on sale. The calculator and all free checklists above remain free.
Safety sources
- CDC — how to create and store an emergency water supply
- CDC — how to make water safe in an emergency
- Ready.gov — power-outage safety sheet
Sources reviewed October 31, 2026. Follow current local water-quality advisories and the instructions for your specific equipment. Fuel-powered generators must always run outdoors, at least 20 feet from building openings; never use them in an enclosed space.
Turn your result into an equipment checklist
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