WaterBOB Emergency Bathtub Water Storage review
By Tom Calder
A clever, low-cost way to bank around 380 litres of clean water in your bath when you get warning of a supply cut, and it packs away to nothing the rest of the time. Its weakness is that it only helps if you have a standard bathtub and enough notice to fill it, and it is effectively single-use once opened.
- Best for
- Households with a standard bathtub who want a large, cheap water reserve to fill when a supply interruption is forecast.
- Skip it if
- You only have a shower, or if you want a reserve that is always ready to go, in which case a few…
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Researched, not used. We haven't used this product. This review is built from the maker's specifications, owner reports and our own sizing.
What we like
- Stores roughly 380 litres of water for a modest outlay and folds flat when not in use
- Sealed food-grade liner keeps water far cleaner than an open tub, and a siphon pump is included
- Simple to deploy in any standard bathtub and much cheaper per litre than stockpiling bottled water
Worth knowing
- Effectively single-use once the seal is cracked, and stored water is only reliably fresh for a few weeks
- Needs a standard bathtub and advance warning to fill, so it is no help in a sudden, unannounced cut
Out of stock when we checked: our alternatives
Closest in size first, then by our score. None of them was showing out of stock when we last checked.
Best for The buy-once reserve — the only tank here made for drinking water (WRAS-approved polymer, Bye-law 30 kit), UK-made, 10-year warranty.
Best for The clever middle ground — 40 litres one person can actually move.
Best for The step past jerry cans — a week-plus of household water in one food-grade tank.
in stock when checkedⓘ As an Amazon Associate, PreparedBritain earns from qualifying purchases. We may earn a commission when you buy, or a fee when you request a quote, through our links. When two products are close, commission can decide which one we pick. A clearly better product always wins. Amazon prices come from Amazon's own product data and show the date and time they were retrieved. Prices at other retailers are checked by us, less often. Prices and stock can change at any time, so always check the retailer's price before you buy.
Our review
The WaterBOB is a food-grade plastic bladder that lines a standard bath and holds up to 100 US gallons, about 380 litres, of tap water with a siphon pump to draw it off. It is a one-time-use reserve you fill when a supply cut is announced, not a container you keep full. For a household with a bath and a few hours' warning, it banks more clean water than anything else at its size.
What it is
WaterBOB describes the bladder as heavy-duty 10 mil food-grade linear low density polyethylene that stays within US Food and Drug Administration guidelines. You lay it flat in the bath, slip the fill sock over the tap and run the water; the maker says filling takes about 20 to 30 minutes. A hand siphon pump is included, and the pack is small enough to live in an airing cupboard, with a listed weight of one pound, about 450 g.
The 100 US gallon figure is the bladder's maximum. WaterBOB says most standard bathtubs hold about 60 to 70 gallons, roughly 230 to 265 litres, and tells you not to fill it above the edge of the tub. The product is American and sold in the UK through importers, so instructions are in US gallons and the maker makes no claim about UK water fittings approval.
How long the water keeps
Because the bladder is sealed, the water is kept away from dust, soap residue and anything that falls into an open bath. WaterBOB says it keeps water fresh and clean for up to 16 weeks depending on humidity and temperature, and advises keeping it out of direct sunlight, which the maker says speeds up the growth of contaminants. If you want to keep the water beyond that, it suggests treating it with purification tablets. Well water should be treated from the start.
It is designed for one use. WaterBOB says a used bladder cannot be checked for damage and the water would need treating and testing if refilled, so once you have emptied it, recycle it and buy another. Budget for that if you expect to use it more than once in a year of works notices.
Where it fits in a UK water plan
The government's Be Ready guidance says bottled water is the safest way to prepare for a water outage and recommends 3 litres of drinking water per person per day for three days. The WaterBOB is the layer above that: washing, flushing, cooking and drinking water in bulk, with the siphon doing the lifting. Our guide to storing emergency water covers how to rotate stored water, and what to do with no water supply explains what your water company owes you.
Its weakness is warning time. A planned interruption, a storm forecast or a boil water notice gives you the hour you need to fill it. A burst main at two in the morning does not, so a few rigid containers kept filled still belong in the cupboard.
How it compares
On our water storage comparison, the ITP 25-litre jerry cans are the always-ready option: fill, stack and rotate. A collapsible 15-litre carrier folds flat like the WaterBOB but holds a fraction of the volume. The Enduramaxx 300-litre tank stores a similar amount permanently, at a far higher cost and with a plumber involved. Nothing else stores this much water for so little cupboard space.
Our verdict
A clever, inexpensive way to hold a bath's worth of clean water the moment a cut is announced, as long as you accept it is single-use and blocks the bath while it is full. Not for you if your bathroom has only a shower, if you would rather keep a reserve permanently ready, or if you want a container you can fill and empty for years.
A researched review, built from the maker's specs, manual and UK listings; facts checked 2 Nov 2026. Sources: WaterBOB: product details and FAQ; WaterBOB: Be Prepared; GOV.UK Be Ready: water supply interruptions or outages.
Who shouldn't buy this
Skip it if you only have a shower, or if you want a reserve that is always ready to go, in which case a few rigid water containers kept filled will serve an unannounced outage better.
Key specs
| Capacity | 379 L |
| Type | Single-use bathtub water bladder (food-grade LLDPE liner) |
This is a Researched review: we haven't used this product. We check every specification against at least two independent sources, re-check the UK price on a schedule where we can track it automatically, and say plainly who it isn't for. Commissions never change a rating.
Questions
How much water does a WaterBOB hold?
Up to 100 US gallons, about 380 litres, but WaterBOB says most standard baths hold 60 to 70 gallons, roughly 230 to 265 litres. Fill it only to the edge of your bath.
How long does water keep in a WaterBOB?
WaterBOB says up to 16 weeks depending on humidity and temperature, kept out of direct sunlight. For longer storage it suggests treating the water with purification tablets.
Can a WaterBOB be reused?
No. WaterBOB says it is designed for one-time use and is recyclable, because a used bladder cannot be checked for damage and refilled water would need treating and testing.
Does it work in a shower or a small bath?
It needs a bath. In a short bath it simply holds less, since you fill it only to the tub's edge. There is no version for a shower tray.
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