Water Storage — Just In Case

Calculate your household's need

Household size

Days to plan for

Extreme heat / heavy exertion (+0.5 gal/person/day) Pregnant or nursing member (+1 gal/day)

# of infants (formula-fed)

# of dogs (avg. size)

# of cats

Your total —

Method	Kills / removes	Time	Cost	Watch for
Boiling	Bacteria, viruses, parasites	1 min rolling boil (3 min above 6,500 ft)	Free	Needs fuel/heat you may not have. Doesn't remove chemicals, heavy metals, or sediment.
Purification tablets	Bacteria, viruses (chlorine dioxide also gets Giardia/Crypto)	30 min – 4 hrs	Low	Iodine tablets aren't safe for pregnant people or thyroid conditions. Doesn't remove sediment.
Filters	Bacteria, protozoa, sediment	Immediate	Medium	Most don't remove viruses unless rated <0.02 micron. Can clog or freeze-damage.
UV pens	Bacteria, viruses, protozoa	~90 sec/liter	Medium	Battery-dependent. Water must be clear — pre-filter anything cloudy first.
Unscented bleach	Bacteria, viruses	30 min wait	Free	8 drops/gallon at 6% concentration, 6 drops/gallon at 8.25%. Must be plain — no scents or additives. Expires ~1 year.

Layer two methods — a stored supply plus a purification backup. Never rely on just one.

Rotation: label every container with the fill date. Commercial bottled water — follow the printed date. Home-filled containers — rotate every 6 months.
Infants: formula requires safe water — bottled or boiled and cooled. Breastfeeding is a genuine resilience advantage here, since it removes the water-treatment step entirely.
Medical needs: dialysis, wound care, and device cleaning all raise water needs above the baseline — talk to your care team about your actual minimum.
Elderly household members: thirst sensation drops with age. Schedule drinking reminders — don't wait for thirst as the signal.
Well / off-grid households: your well pump needs power. Confirm your backup power source can actually run it — don't assume it can just because you own a generator. If you have a pressure tank, know how many gallons it holds. A filled bathtub is a real non-potable reserve for flushing and hygiene.
Pets: see the Pets section of the Household Assessment for exact per-pet water math.