WaterBOB Bathtub Water Storage: How It Works and What to Buy Now
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Updated November 9, 2026
A waterBOB is a heavy plastic liner that sits in your bathtub and holds up to 100 gallons of drinking water. You fill it from the tap when a storm is coming, the liner keeps the water covered, and a small hand pump lets you fill jugs and pots afterwards. When the water plant goes down or a boil-water notice goes out, you still have water for drinking, cooking and washing up.
Can you still buy a waterBOB? The original waterBOB wasn't listed on Amazon when we checked in November 2026. Several makers sell the same thing: a 100-gallon, food-grade bathtub liner, most with a siphon pump. Our picks are below.
On this page:
- How a bathtub water bladder works
- How much water you need
- How to fill and use it
- Keeping the water safe
- What to buy now
- FAQ
How a Bathtub Water Bladder Works
An open bathtub full of water collects dust, hair and soap residue, and you can't easily get the water out. A bathtub bladder fixes both problems. It's a food-grade plastic bag shaped to lie flat in the tub, with a fill opening you attach to the faucet and a cap to keep it closed. Once it's full, a hand siphon pump draws water out into a pot, pitcher or water jug.
It costs little, folds up small in a closet until you need it, and turns the biggest container in your house into clean water storage in a few minutes.
How Much Water You Need
The CDC says to store at least 1 gallon of water per person per day for 3 days, and to aim for a 2-week supply if you can (CDC). That works out to:
| Household | 3 days | 2 weeks |
|---|---|---|
| 1 person | 3 gallons | 14 gallons |
| 2 people | 6 gallons | 28 gallons |
| 4 people | 12 gallons | 56 gallons |
| 6 people | 18 gallons | 84 gallons |
A full 100-gallon bladder covers a family of four for more than two weeks, with water left over for pets and washing. Store more if you live somewhere hot, or have someone pregnant or sick at home.
How to Fill and Use It
- Do it early. Fill it as soon as a storm is in the forecast, while the water is still clean and the pressure is good.
- Lay it out. Unfold the liner flat in a clean, empty tub with the fill opening at the faucet end.
- Fill from the cold tap. Attach the fill tube or opening to the faucet and fill it. Don't use the hot water heater line.
- Cap it. Close the cap tightly so nothing gets in.
- Pump it out. Insert the siphon pump and squeeze to fill a pitcher or jug. Keep the pump clean and in a zip bag between uses.
Keep the bathroom door closed. The CPSC warns that young children can drown in bathtubs and even buckets with a small amount of water, and to never leave a young child alone near any tub or basin with liquid in it (CPSC). A full bladder is still a tub full of water.
Keeping the Water Safe
Water from a treated city supply, sealed in a clean food-grade liner, is good for drinking for the length of a typical storm outage. Follow the maker's guidance on how long to keep it, and treat it if you have any doubt:
- Bleach: for clear water, add 8 drops (a little less than 1/8 teaspoon) of plain, unscented household bleach per gallon, stir and wait at least 30 minutes (CDC).
- Tablets or a filter: purification tablets and a good filter work too. See our water treatment and storage guide.
- If you're on a well or your water utility has already issued a boil-water notice, treat the water before drinking it.
Stored water that isn't commercially bottled should be replaced every six months (Ready.gov), so a bathtub bladder is a storm-time tool, not long-term storage. For water that sits for months, use sealed jugs or water bricks.
What to Buy Now
100 Gallon Bathtub Water Bladder with Siphon Pump
The closest match to the original waterBOB: a food-grade 100-gallon liner that fits a standard tub, with a hand siphon pump in the box. This is the one to get if you only buy one.
Bathtub Emergency Water Storage Bag (100 Gallon)
The budget pick. Same 100-gallon idea for less money; it's a good second liner for another bathroom.
Aquatabs Water Purification Tablets
Backup treatment for stored water, and small enough to live in your bug out bag. + Add to bag~$27 · 0.3 oz
Prepping for a storm? Our storm week shopping list covers what else to buy locally before it hits, and the hurricane guide covers the rest.
WaterBOB FAQ
How many gallons does a waterBOB hold?
Up to 100 gallons in a standard bathtub. A smaller or shallower tub holds less.
How long does water last in a bathtub bladder?
It's meant for the length of a storm outage, not months. Follow the maker's guidance, treat the water if in doubt, and use sealed containers for long-term storage, which Ready.gov says to replace every six months.
Is waterBOB water safe to drink?
Yes, if you fill it with safe tap water before the supply is affected. If you're unsure, add 8 drops of plain household bleach per gallon of clear water and wait 30 minutes, as the CDC recommends.
Where can I buy a waterBOB?
The original waterBOB is hard to find now. Bathtub water bladders from other makers do the same job; the 100 gallon bladder with a siphon pump above is our pick.
Can you reuse a bathtub water bladder?
Most are sold for single use. Check the maker's instructions, and keep a spare in the closet so you're ready for the next storm.
Sources
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