Can You Just Fill the Bathtub for Your Pets?
One bathtub holds more water than most households will ever stage in containers, so this is the question people ask the night before a storm.
A pet authority does tell you to fill it. The ASPCA’s disaster-preparedness page, in its guidance on choosing a safe zone at home, says: “In areas that may lose electricity, fill up bathtubs and sinks ahead of time to ensure that you have access to water during a power outage or other crises.” That sentence promises access to water. The same page’s supply list separately calls for “At least seven days’ worth of bottled water for each person and pet”, to be replaced every two months. The ASPCA does not say how the two relate. Our reading, labeled as ours: the tub is a household reserve and the bottled water is the drinking supply, because the bottled-water line is the one the ASPCA attaches to each person and pet. Reading the tub line as your dog’s water bowl is the mistake to avoid.
What a Bare Tub Fails On
The CDC’s emergency-water page (dated June 27, 2025) never mentions bathtubs, but it sets the container standard. It says it is best to use FDA-approved food-grade water storage containers. If you can’t, the container should meet three criteria:
- “Has a top that can be closed tightly.”
- “Is made of durable, unbreakable materials (not glass).”
- “Has a narrow neck or opening, if possible, so you can pour water out of it.”
A bathtub is an open basin you can’t close and can’t pour from. The CDC also has you wash the container with soap, sanitize it with a bleach solution and let it air-dry before filling, and says not to use containers previously used to hold toxic chemicals such as bleach or pesticides. A tub scrubbed with bathroom cleaner is the kind of surface that standard exists to keep away from drinking water.
Then the pet layer. AVMA’s household-hazards page says products containing bleach can cause stomach upset, drooling, vomiting, diarrhea, severe burns if swallowed, and respiratory tract irritation if inhaled in a high enough concentration. It notes that cats can be particularly sensitive to certain ingredients such as phenols, which matters when the dog and the cat drink from the same reserve. For the bathroom’s other open basin, its instruction is: “Keep toilet lids closed to prevent pets from drinking toilet water treated with toilet bowl cleaning agents, which could irritate their digestive tract.”
AVMA says that about toilets, not tubs. The reasoning transfers, and this part is ours: a filled tub is an open basin of standing water at floor level, in the room where cleaning products get used, reachable by an animal that drinks unsupervised. That is the same hazard shape the toilet-lid advice is about, minus the lid.
The two companies that sell the fix say the same about the surface, and have an obvious reason to. waterBOB’s site says most bathtubs have dirt and soap film that would contaminate the water, and AquaPod lists preventing contamination from dirty bathtub surfaces as a feature. Those are marketing claims that agree with the CDC container standard, not independent findings.
What a Liner Changes, and What It Doesn’t
A bathtub bladder is a food-grade liner you lay in the tub and fill from the faucet, so the water never touches the tub. The two named products, on their manufacturers’ claims:
| Claim |
waterBOB |
AquaPod |
| Capacity |
Holds up to 100 gallons; the maker says most standard bathtubs hold approximately 60-70 gallons |
Recommended capacity is 65 gallons for standard tubs; the FAQ adds that some larger tubs can take up to 100 |
| Material |
10 mil food grade linear low-density polyethylene (LLDPE), which the maker says follows and stays within US FDA guidelines |
Food-grade, BPA-free materials that the maker says meet FDA standards for water storage; the product page also lists a “HACCP certified facility” and calls its resin “HACCP-Compliant” |
| Fill or setup time |
Approximately 20-30 minutes, depending on water flow and tub size |
Setup time of 15 minutes; no fill time published |
| Dispensing |
Siphon pump included |
Built-in siphon pump |
| Reuse |
Intended for one time use |
Designed for single use |
| Stated storage life |
Up to 16 weeks, depending on humidity and temperature |
A recommended storage duration of 8-16 weeks |
AquaPod’s product page ties HACCP to the facility (“HACCP certified facility”) and also calls its resin “HACCP-Compliant”. HACCP is a food-safety management system, so it describes process controls, and the page names no certifier or test for the material touching your water.
waterBOB’s page disagrees with itself: the freshness answer says 16 weeks, and another FAQ answer refers to “the 4 week safe storage time.” Both cannot be the number. Plan to the shorter one, and note that AquaPod’s own range starts at 8 weeks.
Neither company publishes animal-use testing. On waterBOB’s product page the only animal reference is a warning that a pet or sharp object could cause an accidental leak, which is a reason to think about where the cat sleeps, not a safety endorsement. AquaPod’s product page and FAQ mention no pets or animals.
waterBOB’s Be Prepared page does carry a pet line, but it is printed with the quantity missing: “If you have pets, allow a minimum of gallon per day for each dog or cat.” There is no number between “of” and “gallon,” so it is not a usable figure. It is also not a veterinary figure, and it does not scale with the animal. Use the per-pound math above.
Against the Water You Already Store
Volume is not the tub’s weak point. Two 50 lb dogs need roughly 10.9 gallons for 14 days at the flat rate, so even a 65-gallon fill is about six times the pet target, and reaching 100 gallons in 3.5-gallon containers would take about 29 of them.
Timing and mobility are the weak points. waterBOB puts filling at 20 to 30 minutes and AquaPod publishes a 15-minute setup time, so plan on twenty to thirty minutes of running water you still trust, plus setup. It is a tool for emergencies that announce themselves. The CDC’s own description of a water-related emergency is that “safe drinking water may not be available”, and once that is true the tap you planned to fill from is the problem. Both manufacturers call the liner single-use, and it occupies the tub while the water sits there. USGS lists water at 62.3 pounds per cubic foot at 70 degrees F, which works out to about 8.3 pounds per gallon (our conversion), so a filled bladder is roughly 540 to 830 pounds on your bathroom floor, while AVMA’s evacuation-kit instruction is to “store in an easy-to-carry, waterproof container close to an exit.”
So the split for a multi-pet household: containers hold the pet ration, because that is the water that must already exist when a main breaks with no warning, and the only water that goes in the car. A bathtub bladder is a surge reserve you fill when a storm gets a name, sized for the household, and it stays behind when you leave. Stack it on top of the 7 to 14 day container target, never in place of it.
Rotation: How Often to Replace Stored Water
The two authorities set different cadences. The ASPCA says to replace bottled water every 2 months. The CDC, in its general emergency-water guidance, says to rotate stored water every 6 months.
Our read: the ASPCA’s shorter interval is specific to pet preparedness and errs conservative. If you store water specifically for pets, follow the ASPCA’s 2-month cadence. If the reserve is shared between people and pets, the CDC’s 6-month interval is a reasonable compromise, as long as you accept that the ASPCA’s window is the more cautious one.
When Filtered Water Makes Sense
AVMA’s pets-and-disasters page lists contaminated water among the hazards to check for around your home after a disaster. Our reasoning, not AVMA’s: that is a reason to keep pets off floodwater and other unknown water, and to have a backup plan beyond stored bottles, especially in an extended outage or an evacuation that outlasts your supply.
A portable filter like the Sawyer MINI removes 99.99999% of bacteria and 99.9999% of protozoa through a 0.1-micron membrane, per the manufacturer, which covers bacteria and protozoa. Sawyer’s listing does not claim to remove chemical contamination such as fuel or agricultural runoff, so do not assume it does. Sawyer’s own materials also state no animal-specific testing or certification; they frame the product around human and camping use.
A filter is a hedge for the scenario where stored water runs out before help arrives, not a substitute for storing water. If a filter is your primary plan, that is a gap in your prep. For filters versus purification tablets, see our water purification guide.
Get Your Exact Number
Everything above assumes a specific dog at a specific weight for a specific duration. For cats, Cornell’s Feline Health Center gives a lower rate: about 4 ounces of water per 5 pounds of lean body weight per day. Hope Force International states its 1 oz per pound rule for dogs and cats, and Pet Evac Pak gives its range for a “healthy pet”, but neither is a veterinary authority. See our best cat go-bags page for the day counts the authorities do publish for cats, and our emergency food and water storage guide for why the dog rate is not applied to a cat. The pet emergency supply calculator takes your actual animals and duration target and returns a shopping list sized to the math on this page.
Measure one day’s water into a known-volume bowl (the pick holds 3 cups, 24 fl oz) so the number is real, not estimated.
For a full at-home shelter-in-place reserve rather than a carried supply, our long-term pet food and water storage guide covers container sizing, shelf life and rotation at that scale. Our pet water during a drought or water restriction guide covers what changes when the shortage is a drought or a restriction stage rather than a storm.
Vet-Wins Reminder
Water math is a planning exercise. If your dog stops drinking, call your veterinarian, storage plan or not. If you are rationing a limited supply and wondering how long your dog can safely wait, our guide on how long a dog can go without water in an emergency covers the dehydration signs that mean act now, and why there is no honest survival countdown. If a pet has been exposed to floodwater or an unknown water source and is vomiting, has diarrhea or is lethargic, call your veterinarian rather than waiting.
For suspected water contamination or poisoning, ASPCA Animal Poison Control is available 24 hours a day at (888) 426-4435 (a consultation fee may apply).
How We Chose
The container, bathtub liner, bowl and filter above are chosen from manufacturer-published specifications and the product pages listed in each spec table’s source column. EmergencyPetPrep did not test any of them. Where a manufacturer did not publish an animal-specific claim, as with the Sawyer filter, this page says so instead of assuming it applies. See our review methodology.