Sizing, Storing, and Treating Emergency Water for the 72-Hour Plan

FIELD NOTE
Type: Field Report
Related Project: The 72-Hour Plan
System Status: Operational; expanding stored volume
Date / Time: July 14, 2026; Arizona time
Location / Environment: Phoenix metropolitan area / Sonoran Desert; indoor household storage under extreme-heat conditions
Equipment / Software: Five filled blue 5-gallon stackable potable-water containers; bottled-water reserve; unscented household bleach; water-purification tablets; LifeStraw filters; camp pots; portable propane stoves; household gas; wood-fire backup; CDC, FEMA, EPA, USGS, Arizona public-health, and veterinary references
Outcome: The household has an operational 72-hour water capability and known-good storage, boiling, bleach, tablet, and portable-filter methods. The supply is being expanded toward a rounded 90-gallon target for three adults, one 30-pound dog, and one 10-pound cat for fourteen days.
Last Verified: July 14, 2026

Summary

A water plan is not just a stack of containers. It is a controlled supply, a safe way to dispense it, multiple known-good ways to make microbially suspect water safer, a sanitation plan that does not consume the drinking reserve, and an action threshold that starts resupply or relocation before the reserve reaches zero.

The Centers for Disease Control and Prevention recommends storing at least one gallon of water per person per day for three days and trying to store a two-week supply when possible. The minimum must increase for hot weather, illness, pregnancy, medical needs, and pets. A separate CDC drinking-water advisory planning guide uses two gallons per person per day when temperatures are likely to be very warm.

Fallback Engineering operating rule: We size the Phoenix-area protected reserve at two gallons per adult per day, add the animals’ water, and maintain a rounded 90-gallon target for fourteen days. The two-gallon rate is our conservative desert-heat design basis, not a universal government minimum.

The household consists of three adults, one 30-pound dog, and one 10-pound cat, with no special medical or mobility water requirements. Five filled 5-gallon stackable containers provide 25 documented gallons of potable water. A rotating bottled-water reserve adds more capacity, and all water is stored in a closet inside the conditioned house. The 25-gallon container inventory alone exceeds the approximately 19-gallon 72-hour target for the people and animals.

The treatment side is also operational. We keep unscented bleach in the house; water-purification tablets, LifeStraw filters, small camp pots, and portable propane stoves in the go bags; household gas for boiling; and wood as a final heat-source backup. These are familiar, previously used methods. The work now is capacity expansion and inventory discipline—not proving that basic boiling, chlorination, tablets, or filtration work.

Objective

Define a defensible 72-hour minimum and a longer home-storage objective for extreme heat.
Provide a repeatable method for calculating people, pets, weight, container count, and storage load.
Establish safe container selection, sanitation, filling, storage, dispensing, inspection, and rotation practices.
Set an escalation sequence for advisories, falling inventory, and complete loss of the stored supply.
Document boiling, chemical disinfection, and portable-filter limits without implying that any method removes every contaminant.
Document the working household configuration, quantify the remaining 14-day storage gap, and identify the few inventory details still needed.

Context

A municipal outage is only one failure mode. Loss of pressure, a boil-water advisory, chemical contamination, an extended power failure, wildfire, flooding, damaged distribution lines, or a regional heat emergency can leave water flowing but unsafe. The plan must respond to water quality as well as quantity.

Ordinary household behavior cannot continue on an emergency reserve. The U.S. Geological Survey estimates indoor home use at roughly 80 to 100 gallons per person per day. Emergency storage is therefore a separate operating mode: no normal showers, laundry, dishwashing, or routine toilet flushing from protected water.

Heat changes the risk. Water demand rises with temperature and exertion, while a power failure can also remove air conditioning. If the home cannot remain safely cool, relocation becomes a water decision as well as a heat decision. Stored water should buy time to move safely; it should not justify remaining in a dangerous indoor temperature.

Setup

Planning definitions

Potable water: water verified or treated for drinking, cooking, medications, tooth brushing, ice, infant formula, and pets.
Protected reserve: sealed potable water that is not used for flushing, cleaning, evaporative cooling, or other utility tasks.
Utility water: nonpotable water reserved for uses allowed by the specific source and incident. It must be labeled and kept separate.
Daily burn rate: gallons of protected water actually used in 24 hours. Capacity without a measured burn rate is only an estimate.

Calculation

People: people × days × planning rate.
Pets: each pet’s measured high-use day × days, rounded up.
Total: people + pets + documented medical or food-preparation needs.

Current household calculation

Requirement	72 hours	14 days
Three adults at 2 gal/person/day	18 gal	84 gal
30 lb dog, approximate maintenance range	0.5–0.7 gal	2.2–3.3 gal
10 lb cat, approximate maintenance range	0.2–0.3 gal	0.7–1.1 gal
Calculated total	18.7–19.0 gal	86.9–88.4 gal
Operational storage target, rounded up	20 gal	90 gal

Pet figures use the Merck thermoneutral maintenance range as a cross-check. We do not ration animals to the low end; we round the household total upward and provide more during heat, activity, illness, or unusual loss.

Current documented inventory: 25 gallons in five filled 5-gallon potable-water containers, plus the bottled-water reserve. The fixed containers already exceed the rounded 20-gallon 72-hour target. Before counting bottled water, the 14-day expansion gap is 65 gallons, equivalent to thirteen additional 5-gallon containers. Each gallon counted in the bottled reserve reduces that gap by one gallon.

At 90 gallons, the water alone will weigh about 750 pounds. The indoor closet is the correct thermal environment and has room to expand, but the final layout must distribute that load safely and keep containers accessible without relying on overloaded shelving.

The table below shows water for people only. It excludes container weight, pets, and special needs. Water weighs approximately 8.33 pounds per gallon, according to the USGS.

People	72 hr at 1 gal/day	72 hr Phoenix target at 2 gal/day	14 days at 1 gal/day	14-day Phoenix target at 2 gal/day	Approx. water weight: 72 hr / 14-day Phoenix targets
1	3 gal	6 gal	14 gal	28 gal	50 lb / 233 lb
2	6 gal	12 gal	28 gal	56 gal	100 lb / 467 lb
3	9 gal	18 gal	42 gal	84 gal	150 lb / 700 lb
4	12 gal	24 gal	56 gal	112 gal	200 lb / 933 lb
5	15 gal	30 gal	70 gal	140 gal	250 lb / 1,166 lb
6	18 gal	36 gal	84 gal	168 gal	300 lb / 1,399 lb

Baseline and desert-heat planning quantities. Weights are rounded and do not include containers or shelving.

Pet water

The Merck Veterinary Manual gives an approximate thermoneutral maintenance range of 44 to 66 milliliters per kilogram of body weight per day for dogs and cats. A 50-pound animal would be roughly 0.26 to 0.40 gallon per day by that estimate. Heat, activity, dry food, lactation, vomiting, diarrhea, medication, and disease can raise need substantially.

I will not use that range as a ration. The household plan should use each animal’s measured high-use day in hot weather or a veterinarian’s direction, then round up for bowl loss and uncertainty. Pets need the same microbiologically safe water used by people.

Container load and handling

Nominal size	Water alone	Primary role	Handling note
1 gallon	8.3 lb	Portable, redundant, easy to issue	Easy for most adults to move; more packaging
5 gallons	41.7 lb	Portable home storage	Requires controlled lifting and a spigot or pump
7 gallons	58.3 lb	Dense portable storage	Heavy and awkward when full
55 gallons	458 lb	Stationary bulk reserve	Nearly half a ton with drum and hardware; fill, support, secure, and drain in place

No bulk container should be placed on a shelf, floor, or vehicle solely because it fits. The loaded structure, point load, tie-down, access path, drainage, and lifting method all have to be checked first. Smaller containers provide portability and failure isolation; bulk containers provide density. A layered system uses both.

Procedure

1. Build and maintain the stored supply

Calculate before buying. Enter every person, pet, special medical need, 72-hour quantity, 14-day quantity, existing gallons, and deficit.
Use commercially bottled water first when practical. CDC identifies unopened commercially bottled water as the safest and most reliable emergency source. Observe the manufacturer’s date and storage instructions.
Choose safe refillable containers. Use food-grade containers with tight lids and openings small enough to prevent hands or utensils from entering. Do not use containers that held chemicals. Avoid glass and containers that held milk or fruit juice because they are difficult to sanitize reliably and are prone to breakage or microbial residue.
Sanitize refillable containers. Wash with dish soap and rinse completely. Mix one teaspoon of plain, unscented 5%–9% sodium-hypochlorite bleach into one quart or liter of water. Close the container, shake so the solution touches every interior surface, wait at least 30 seconds, drain, and air-dry or rinse with safe water. This is a container-sanitizing solution, not the drinking-water disinfection dose.
Fill without recontamination. Use water from a treated public supply or another verified potable source. Do not touch the inside of the cap or opening. Close tightly.
Label clearly. Mark “DRINKING WATER,” the fill date, capacity, and rotation date. Mark utility water “NOT FOR DRINKING” and physically separate it.
Store cool, dark, and chemically isolated. CDC recommends approximately 50–70°F when possible, away from sunlight, gasoline, pesticides, solvents, and other toxic substances. In the Phoenix area, an attic, hot garage, outdoor shed, or parked vehicle is not the preferred primary long-term location.
Secure and stage for use. Protect containers from flooding, puncture, tipping, freezing, pests, and vehicle impact. Keep an appropriate pump, wrench, hose, or spigot with the container.
Rotate and inspect. Replace self-filled water every six months. Observe the printed date for commercial water. At rotation, inspect for leakage, swelling, damaged seals, odor, algae, label loss, and degraded hardware. Keep treatment bleach fresh; CDC directs users to check the label and use an unexpired product, generally less than one year old for emergency disinfection planning.
Dispense cleanly. Wash or sanitize hands, use the dedicated pump or spigot, and never dip cups, hands, or hoses into a protected container. Close it immediately and track the date opened.

2. Identify the advisory before treating water

Follow the water provider and public-health authority. The same response is not safe for every advisory. The CDC advisory definitions provide this decision framework:

Condition	Meaning	Household action
Boil-water advisory	Microbial contamination is known or possible	Use commercial water or boil as directed. Use treated water for drinking, food, teeth, ice, medications, formula, and pets.
Do-not-drink advisory	Chemicals, toxins, or another hazard may be present	Use an approved alternate supply for all ingestion. Boiling does not remove the hazard and can concentrate some chemicals.
Do-not-use advisory	Contact itself may be dangerous	Do not drink, cook, wash, bathe, brush teeth, make ice, or give it to pets. Use only the alternate source and uses authorized by officials.
Pressure loss with no guidance yet	Contamination may have entered the system	Stop ingestion, preserve stored water, seek provider guidance, and treat the tap supply as suspect until cleared.

Stop connected ice makers and refrigerator dispensers during an advisory. After clearance, follow provider instructions for flushing plumbing, replacing filters, cleaning appliances, discarding ice, and returning the water heater to service.

3. Act before stored water reaches zero

The following thresholds are project operating recommendations. They are intentionally early because heat, transport disruption, and uncertain restoration times can erase the apparent margin.

Protected supply remaining	Required action
72 hours or more	Count sealed gallons daily, calculate the actual burn rate, monitor official information, and stop all utility use of potable water.
Less than 72 hours	Put verified resupply or relocation in motion. Confirm the source, route, hours, containers, transport capacity, and the needs of every person and pet.
Less than 48 hours	Relocate or request assistance unless replenishment is physically secured. Do not treat a promise, announced distribution point, or untested filter as water on hand.
No protected water	Use only verified household sources or treat a source that is reasonably free of chemical, fuel, sewage, flood, or radiological contamination. Reduce heat exposure and exertion, contact local emergency services or relief resources, and move to a verified potable supply. Do not wait for dehydration symptoms.

FEMA guidance says not to ration drinking water unless authorities direct it. The safe response is to eliminate low-priority water use, stay as cool and inactive as conditions allow, and obtain more water—not to deliberately under-hydrate. Anyone with confusion, fainting, inability to keep fluids down, very low urination, or signs of heat illness needs urgent medical help.

4. Recover water already inside the home

The CDC lists household sources that may remain usable if they were potable before the incident and have not been contaminated:

Uncontaminated ice made before the incident.
Water from a conventional tank-type water heater.
Water trapped in household supply pipes.
Clear water from a toilet tank that has no cleaner, disinfectant tablet, chemical additive, or visible contamination. Never use water from the toilet bowl.
Liquid from canned fruit and vegetables and other sealed, nonalcoholic beverages as supplemental fluid and food resources.

Water-heater recovery: only proceed if the tank and incoming supply were not chemically or biologically contaminated. Turn off electrical power or place the gas control in the manufacturer-approved off position; never energize an empty tank. Close the cold-water inlet to isolate the tank. Allow dangerously hot water to cool. Open a hot-water faucet to admit air, attach an appropriate hose or use the drain valve, and collect from the bottom drain. Sediment is possible; prefilter and disinfect if microbial safety is uncertain. If the appliance, gas control, drain, or contamination status is unfamiliar, use a qualified technician rather than improvising.

Pipe recovery: close the home’s main water valve before contaminated water can enter. Open the highest faucet to admit air, then collect from the lowest faucet. The main-valve location, required tool, and direction of operation should be labeled before an emergency.

Do not use home radiators, hot-water boilers, waterbeds, vehicle cooling systems, dehumidifier condensate, or toilet bowls as drinking sources. Pool and spa water is a utility-water source only unless public-health authorities explicitly direct otherwise; ordinary field boiling, bleach, and backpacking filters do not address the full chemical load.

5. Obtain and treat outside water only within the method’s limits

The preferred order is: verified emergency distribution, sealed commercial water, a known potable private source, recoverable household water, and only then untreated rain, spring, stream, pond, lake, or melted clean snow. Surface water and roof runoff can appear clear while carrying microbes or chemicals. Floodwater, water with fuel or solvent odor, suspicious color or sheen, mine or industrial runoff, salty water, and water subject to a do-not-use or do-not-drink advisory are not candidates for the methods below. Use another source or relocate.

For cloudy water, allow sediment to settle and pour the clearer layer through a clean cloth, paper towel, or coffee filter. This improves treatment but does not disinfect the water.

Boiling

Prefilter cloudy water.
Bring it to a full rolling boil.
Boil for one minute. Above 6,500 feet elevation, boil for three minutes.
Cool naturally in a clean, covered container. Do not add ice of uncertain safety.

For Phoenix-area elevations, the one-minute rule applies. The three-minute rule matters when the plan moves into Arizona high country. Boiling kills common disease-causing organisms but does not remove salts, fuels, toxic chemicals, or radioactive material and can concentrate some dissolved contaminants.

Household bleach disinfection

Use the current CDC label-based instructions. Use only regular, unscented liquid household chlorine bleach whose label lists 5%–9% sodium hypochlorite. Do not use scented, color-safe, splashless, gel, powdered, or bleach-with-cleaner products. Never mix bleach with ammonia, acids, or other cleaners.

Water volume	Clear water: 5%–9% bleach	Cloudy, colored, very cold, or murky water
1 quart or liter	2 drops	4 drops
1 gallon	8 drops	16 drops
5 gallons	40 drops, approximately 1/2 teaspoon	80 drops, approximately 1 teaspoon

Stir well and wait at least 30 minutes before use. Drop size and bleach concentration vary, so the current product label and current CDC table control; an old chart copied without its concentration is not sufficient. Chemical disinfectants may be less effective against parasites such as Cryptosporidium and Giardia than boiling. If water is very cold, warm it when possible and follow the longer contact time on an approved product label.

Portable filtration

Claimed target	Minimum feature to look for	Remaining action or limitation
Parasites	Absolute pore size of 1 micron or smaller	Does not by itself establish virus, chemical, or dissolved-contaminant safety.
Bacteria	Absolute pore size of 0.3 micron or smaller	Verify the manufacturer’s specific claim and test standard; most portable filters still do not remove viruses.
Viruses	A purifier or treatment specifically validated for viruses	Ordinary backpacking filters are not enough. Follow filtration with boiling or an appropriate disinfectant when viral contamination is possible.
Chemicals, fuel, salt, or radioactivity	No blanket field-filter assumption is acceptable	Use a different source unless a certified device specifically covers the known contaminant within its rated capacity.

A filter must be evaluated as a system: exact model, absolute versus nominal pore size, verified contaminant claims, cartridge life, storage after use, freeze damage, replacement elements, flow rate, operator effort, and gallons per day. The household needs a timed throughput test with the actual source water. Owning a filter is not the same as having enough treated water.

6. Protect drinking water through sanitation discipline

Reserve potable water for drinking, medications, essential food preparation, tooth brushing, infant formula, wound care when directed, and pets.
Use no-cook or low-water foods. Do not spend protected water washing raw ingredients or dishes when a safe disposable or wipe-clean option exists.
Wash hands with safe water and soap at critical times. If that is unavailable, use hand sanitizer containing at least 60% alcohol when appropriate; visibly dirty hands still require cleaning.
Do not flush toilets with protected drinking water. An efficient modern toilet may use 1.28 gallons per flush. Four people flushing once daily for three days would use about 15.4 gallons—more than the 12-gallon federal baseline for those four people.
Pre-stage a portable or dry sanitation method, liners, absorbent material, gloves, hand hygiene, and a disposal plan consistent with local public-health direction.
Use pool water or other suitable utility water for flushing only if the sewer system is confirmed operational and officials have not prohibited flushing. A sewer outage or backup requires the dry sanitation plan.

Observations

The federal one-gallon figure is a minimum planning floor. It is not a promise of comfort or adequacy in Phoenix heat.
The household’s five filled containers provide 25 gallons and already cover the rounded 20-gallon 72-hour target without counting bottled water.
The 14-day goal is 90 gallons: 84 gallons for the adults and a rounded allowance for the dog and cat. The known fixed-container gap is 65 gallons minus the bottled-water inventory.
The inside closet protects the supply from the extreme temperatures found in a Phoenix garage, shed, attic, or vehicle and has room for additional 5-gallon containers.
Mass and load distribution remain design constraints. The completed 90-gallon supply will weigh about 750 pounds before containers.
Storage and treatment solve different failures. The household already has redundant, familiar treatment methods, but those methods still do not make chemically contaminated water safe.
LifeStraw filters, purification tablets, bleach, propane boiling, household gas, and wood backup provide useful redundancy across home and go-bag configurations.
The best time to isolate plumbing, secure resupply, or relocate is before the remaining supply becomes physically critical.
Normal toilet flushing and household cleaning can consume an emergency reserve faster than drinking does, so utility water and dry sanitation remain separate requirements.

Results

The household water system is operational at the 72-hour level and is being expanded toward the 14-day objective:

Household: three adults, one 30-pound dog, and one 10-pound cat; no special medical or mobility requirement.
72-hour target: 20 gallons after rounding the adult and animal calculation upward.
Current fixed supply: 25 gallons of potable water in five filled, stackable 5-gallon containers, plus a bottled-water reserve.
14-day target: 90 gallons total. The known remaining gap is 65 gallons minus the exact bottled-water inventory.
Storage: inside a conditioned-house closet with space for more 5-gallon containers.
Chemical treatment: unscented household bleach and purification tablets are on hand and familiar.
Filtration: LifeStraw filters are staged in the go bags and used within their model-specific limits.
Heat treatment: camp pots and portable propane stoves are staged in the go bags; household gas is available, with wood as a backup heat source.
Operating practice: self-filled water is rotated, protected water is separated from utility use, and resupply or relocation begins before the reserve reaches zero.

What failed or remains uncertain

The storage and treatment methods are known good and have been used before. The remaining work is configuration detail and capacity expansion, not basic-method validation:

Count the bottled-water reserve by bottle count and bottle volume, convert it to gallons, and record the normal turnover method.
Record the fill and rotation dates for all five 5-gallon containers.
Verify the closet floor and any shelving for the planned load, which approaches 750 pounds of water at the 90-gallon target.
Record purification-tablet expiration dates and the exact LifeStraw models and rated capacities for maintenance tracking.
Document the primary and alternate verified resupply locations and the heat-driven relocation destination.

A remaining technical limit is chemical contamination. The general-purpose storage, boil, bleach, tablet, and portable-filter methods in this note do not constitute a chemical-treatment capability. The operational answer to an unknown chemical, fuel, radiological, or salt hazard is an approved alternate source.

Conclusion

The household already has the five linked capabilities required for a credible 72-hour water system: protected potable volume, safe indoor storage and dispensing, multiple treatment methods, a low-water operating concept, and an early resupply or relocation threshold. The five filled containers cover the 72-hour target even before the bottled reserve is counted.

The next build step is straightforward: count the bottled water, subtract it from the rounded 90-gallon goal, and add 5-gallon containers until the gap is closed. If none of the bottled reserve is credited, thirteen additional full containers would bring the fixed supply from 25 to 90 gallons. The finished supply will weigh roughly 750 pounds, so placement and load distribution are part of the build.

The treatment system does not need to be rediscovered. Bleach, purification tablets, LifeStraw filtration, propane and gas boiling, and wood backup are known tools in this household. They need current labels, expiration dates, model capacities, fuel, and routine inventory checks so the proven methods remain available when required.

Next actions

Count the bottled-water reserve and convert the total to gallons.
Subtract the complete on-hand inventory from the 90-gallon target.
Add filled 5-gallon potable-water containers until the remaining gap is closed.
Verify the closet floor and shelving for the final load and distribute approximately 750 pounds safely.
Label every container with capacity, fill date, and six-month rotation date.
Record the purification-tablet expiration dates and exact LifeStraw models and capacities.
Keep fresh unscented bleach, propane, camp pots, and ignition methods with their respective home or go-bag systems.
Document the main shutoff, tank-water-heater recovery procedure, verified resupply locations, and heat-driven relocation destination.
Maintain the bottled-water skid as a rotating, immediately accessible layer rather than allowing it to become an uncounted reserve.