01 — Infants
Formula preparation requires treated water, and the standard changes for high-risk infants
The CDC's emergency infant feeding guidance is clear: during any water disruption, use commercially bottled water for formula preparation until local authorities confirm the tap water is safe. If bottled water is not available and tap water is the only option, boil it for one minute and allow it to cool to room temperature before mixing formula.
The risk level is higher for three categories of infants: those younger than two months, premature infants, and infants with weakened immune systems. These infants are at elevated risk from Cronobacter, a bacteria that can survive in dry powdered formula. The American Academy of Pediatrics and the CDC both specify that for these high-risk infants, water used to prepare formula should be boiled and still quite hot when mixed with the powder, so the heat kills any bacteria in the formula itself, not just the water.
Water contaminated with chemicals or toxins cannot be made safe by boiling. This applies to formula preparation as fully as to adult drinking water. If a chemical advisory is in effect rather than a boil-water advisory, sealed bottled water is the only appropriate option.
Infants under 2 months, premature infants, or immunocompromised infants
Elevated risk from Cronobacter in powdered formula; immune systems cannot handle contamination that healthy older infants may tolerate.
Use bottled water when possible. If boiling tap water, keep it hot when mixing formula (do not let it cool fully first) to kill bacteria in the powder. Cool the prepared formula before feeding.
02 — Older adults
Older adults lose the thirst signal that younger people rely on
Dehydration is one of the ten most frequent causes of hospitalization for adults over 65 in the United States. The primary reason is physiological: thirst sensation diminishes with age. A landmark study found that healthy older men deprived of water for 24 hours reported no significant increase in subjective thirst compared to younger controls, even as their plasma osmolality rose to levels that would have produced strong thirst in younger people.
UCLA Health reports that up to 40 percent of adults older than 65 experience chronic dehydration, and that the consequences include fatigue, confusion, increased fall risk, and urinary tract infections. During an emergency, when stress, heat, and physical activity may increase fluid needs, an older adult who is not thirsty may still need to drink.
The practical implication for emergency planning is to build scheduled drinking into the routine rather than relying on thirst as the signal. Offer water at regular intervals. Older adults with dementia or cognitive impairment may be unable to communicate thirst even if they do experience it. Anyone caring for an older adult during a disruption should treat regular hydration as a caregiving task, not a personal responsibility left to the individual.
03 — Immunocompromised people
People with weakened immune systems may need additional precautions beyond a standard boil-water advisory
The CDC's drinking water advisory guidance identifies people with weakened immune systems as a population that may need to take additional steps even when water meets standard boil-water advisory requirements. Boiling for one minute addresses most biological threats. For immunocompromised individuals, this standard remains appropriate during a boil-water advisory, but the margin for error is smaller: water that is questionably treated, stored in a contaminated container, or re-contaminated after treatment poses greater risk than for a healthy adult.
People in this group include those receiving chemotherapy, those living with HIV/AIDS, transplant recipients on immunosuppressive medication, and people with certain autoimmune conditions. During a disruption, sealed commercially bottled water is the lowest-risk option for this group. If bottled water is not available, boil and cool water carefully and store it in a clean, sealed container used only for drinking water.
Anyone in this group who has specific medical guidance about water quality from their care team should follow that guidance rather than standard public health advisories, which are written for the general population.
04 — Pets and livestock
Pets need treated water during a boil-water advisory. Livestock needs are measured in gallons per day, not cups.
The CDC's boil-water advisory guidance is explicit: give pets commercially bottled water or boiled water that has cooled during an active advisory. Pets can contract the same waterborne pathogens that affect people, and can also spread germs back to people through contact. A dog or cat that drinks contaminated water is a vector risk for the rest of the household, not just a health concern in itself.
Livestock needs are a different scale of planning problem. A typical dairy cow requires 30 to 50 gallons of water per day. This figure climbs significantly in hot weather and during peak milk production. Beef cattle need 7 to 25 gallons daily depending on size and ambient temperature. Horses need 8 to 12 gallons per day. These volumes make a disruption to well water or municipal supply a serious agricultural emergency, not a minor inconvenience, and require planning for an alternative water source or emergency delivery well before any disruption occurs.
| Animal | Daily water need (approx.) | Notes |
|---|---|---|
| Dog (medium, 50 lb) | 0.5 gallon | Treat same as human water during boil advisory |
| Cat | 0.25 gallon | Treat same as human water during boil advisory |
| Horse | 8–12 gallons | Increases significantly in heat or during work |
| Beef cattle | 7–25 gallons | Wide range by size, temperature, and feed type |
| Dairy cow | 30–50 gallons | Peak demand during high production and hot weather |
Livestock water planning requires an on-property water reserve, a generator to run well pumps during outages, or a relationship with a bulk water delivery service. None of these can be arranged after a disruption begins. For households with livestock, water resilience planning is not optional.
Quick reference
- Use bottled water for infant formula during any water disruption; boil and cool tap water only if no bottled water is available
- For infants under 2 months, premature, or immunocompromised: mix formula with water that is still very hot to kill bacteria in the powder, then cool before feeding
- Older adults lose thirst sensation with age; schedule drinking intervals rather than waiting for them to ask
- Up to 40% of adults over 65 experience chronic dehydration; emergency conditions increase this risk further
- Immunocompromised people should default to sealed bottled water during disruptions; sealed commercial water has the smallest contamination risk
- Pets need treated water during a boil advisory; they can contract and transmit the same waterborne pathogens as humans
- A dairy cow needs 30 to 50 gallons of water per day; livestock water disruptions require advance planning, not emergency improvisation
Primary sources
- CDC — Prepare and Store Powdered Infant Formula in an Emergency: Use bottled water; boil if no bottled water available; follow specific steps for high-risk infants.
- CDC — Preventing Cronobacter in Infants: For high-risk infants, mix formula with hot boiled water (not fully cooled) to kill bacteria in the powder itself; cool before feeding.
- CDC — Drinking Water Advisories: An Overview: Pets can get sick from same germs as people; give pets bottled or boiled water during a boil advisory.
- UCLA Health — Hydration and Older Adults: Up to 40% of adults over 65 experience chronic dehydration; thirst sensation diminishes with age; one study found older men did not feel increased thirst after 24 hours without water.
- PMC — Hydration Status in Older Adults (peer-reviewed review): Blunted thirst sensation, reduced renal concentrating ability, and cognitive impairment all contribute to dehydration risk in older adults.