01 — Pool water
Pool water is useful for sanitation. It is not suitable for drinking without filtration that removes dissolved chemicals.
A backyard swimming pool represents a large volume of water, which makes it an obvious resource during an emergency. The practical answer is more limited than it appears. Pool water is appropriate for toilet flushing, washing, and general sanitation. For drinking and cooking, it requires treatment that most households cannot perform effectively in the field.
The primary concerns with pool water for drinking are not the chlorine, which is at concentrations similar to municipal water, but the additional chemicals commonly added for pool maintenance. Cyanuric acid, a stabilizer used with most outdoor pool chlorine products, is classified by the EPA as a drinking water pollutant. It does not decompose naturally and accumulates in pool water over a season. Boiling, standard carbon filtration, and chemical disinfection do not remove cyanuric acid. Algaecides, pH adjusters, and other pool chemicals present additional unknowns.
Additionally, a pool that has been recently shocked may have chlorine levels far above the safe drinking range. At very high chlorine concentrations, consumption can cause throat and stomach irritation.
Appropriate uses
Toilet flushing, floor washing, body washing (non-wound), laundry, outdoor plant irrigation. Pool water is useful for the bottom tiers of the water priority hierarchy.
Not appropriate without specialized treatment
Drinking or cooking. Standard boiling and bleach treatment do not remove cyanuric acid, algaecides, or other dissolved pool chemicals. Reverse osmosis is required to remove these, which is not a field capability.
02 — Waterbed water
Waterbed water contains preservative chemicals that make it unsafe to drink under any circumstances
Do not consume waterbed water
Waterbed water contains algaecide and other chemical preservatives specifically added to prevent microbial growth in the sealed mattress. These chemicals are intentional additions, not incidental contamination, and cannot be removed by boiling, filtering, or chemical disinfection.
Waterbeds hold 150 to 250 gallons of water in a large sealed vinyl mattress. It looks like a large reserve of water, and that appearance leads some people to consider it during an emergency. The contents are not safe to drink for a straightforward reason: manufacturers add biocide chemicals to prevent algae and bacteria from growing in the warm, dark, sealed environment of the mattress. Without these chemicals, the water would quickly become a health hazard. With them, the water is chemically treated in a way that makes it unsuitable for consumption.
The water can be used for non-consumption sanitation purposes including toilet flushing, cleaning surfaces, and outdoor irrigation. For any use that involves contact with the skin or mucous membranes, check the product label for the specific chemicals used in your mattress conditioner before using the water for bathing.
03 — Medical and special water needs
The one-gallon baseline was designed for a normally active person in a temperate environment. Many households need significantly more.
The CDC's baseline of one gallon per person per day is a survival minimum for a normally active person in moderate conditions. It is specifically described as a minimum, not a comfortable or realistic target for most emergency scenarios. Several conditions reliably increase water needs beyond this baseline, and planning that ignores them will leave household members under-supplied.
| Condition or factor | Additional daily need | Notes |
|---|---|---|
| Hot climate or summer emergency | Double baseline or more | CDC notes water needs can double in very hot temperatures; perspiration increases fluid loss significantly |
| Physical labor or exertion | Significant increase; varies by activity | Emergency cleanup, evacuation on foot, or debris removal can double or triple fluid needs |
| Nursing mothers | Approximately 0.5 gallon extra | Breast milk production increases fluid requirements substantially |
| Pregnancy | Moderate increase | Increased blood volume and metabolic demands raise daily fluid needs |
| Fever, diarrhea, or vomiting | Significant increase; varies by severity | Illness dramatically accelerates fluid loss; rehydration is critical |
| Medication-induced fluid needs | Consult prescribing physician | Diuretics, certain heart medications, and others increase fluid requirements or impair kidney regulation |
| Dialysis patients | Highly individualized; consult care team | Fluid restriction or specific water quality requirements may apply; emergency plan must account for dialysis access |
The practical approach to medical water planning is to work backward from the individuals in the household rather than forward from the standard baseline. For anyone with a chronic condition affecting fluid needs, a medication list, or a care plan, ask the relevant care team specifically about emergency water requirements before a disruption occurs. These questions are much harder to answer after the fact.
Ready.gov notes that the one-gallon minimum is for a normally active person and specifies that children, nursing mothers, and sick people may need more. The CDC recommends storing more water for these populations when planning a household supply.
Quick reference
- Pool water is appropriate for toilet flushing and cleaning; not for drinking or cooking without reverse osmosis to remove cyanuric acid and other pool chemicals
- Boiling and bleach treatment do not remove cyanuric acid, algaecides, or dissolved pool additives
- Waterbed water contains chemical preservatives added by the manufacturer; it is unsafe to drink under any circumstances
- Waterbed water can be used for toilet flushing and outdoor irrigation; check the label before using for bathing
- The one-gallon per person per day baseline applies to a normally active person in moderate conditions; this is a floor, not a target
- Hot weather can double water needs; physical labor can double or triple them
- Nursing mothers need approximately an extra half gallon per day; illness dramatically increases fluid loss
- Anyone with a chronic medical condition, dialysis requirement, or medication-related fluid need should develop a specific emergency water plan with their care team
Primary sources
- CDC — How to Create an Emergency Water Supply: Baseline of 1 gallon per person per day; store more for pregnant women, people who are sick, pets, and those in hot climates; try to store a 2-week supply.
- Ready.gov (FEMA) — Water: A normally active person needs at least three-quarters of a gallon of fluid daily; water needs vary with age, health, physical condition, activity, diet, and climate; in very hot temperatures water needs can double; children, nursing mothers, and sick people may need more.
- PMC — Health Risk of Cyanuric Acid in Swimming Pool Water (peer-reviewed review): Cyanuric acid accumulates in pool water over time, does not decompose easily, and poses health risks; high concentrations reduce chlorine disinfection effectiveness; EPA classifies it as a drinking water pollutant.