When the taps stop, water becomes the single most important thing in your home. A burst main, a contamination alert or a wider emergency can cut your supply with little warning, and shops sell out of bottled water within hours. The good news is that storing a sensible reserve is cheap, simple and low-maintenance. This guide explains how much to keep, which containers to trust, and how to look after your supply so it is safe when you need it.
How Much Water to Store
For drinking alone, plan on at least two to three litres per person per day. That keeps an adult hydrated but leaves nothing for anything else. Once you add cooking, washing up and basic hygiene, a common planning figure is around ten litres per person per day for all uses. Do not forget pets, which need roughly 50 millilitres per kilogram of body weight daily. Children, nursing mothers and anyone unwell will need more, and hot weather or physical effort pushes demand higher still.
A realistic starting target is three days of water for everyone in the household, then building towards a week as space allows. For one person, three days at ten litres a day is thirty litres; a family of four needs around 120 litres for the same period. That sounds a lot, but it is only a handful of jerry cans tucked under the stairs or in a garage corner.
Choosing the Best Containers
Use only food-grade containers designed to hold drinking water. Rigid HDPE jerry cans in blue or green are the standard choice, usually sold in five, ten and twenty-litre sizes, with a tap or spout for controlled pouring. You can buy them from Go Outdoors, Screwfix and Amazon, often for only a few pounds each. Larger 25-litre barrels suit garages, while collapsible carriers are handy for topping up from an alternative source during an emergency.
Avoid storing water in old milk cartons or fruit-juice bottles. Their plastic is not built for long storage, and milk sugars and proteins cling to the inside no matter how well you rinse, feeding bacteria. Commercially bottled water in its original sealed PET bottles is fine as sold. Whatever you choose, make sure lids seal tightly and wash new containers with warm soapy water before their first fill.
Storing Tap Water or Bottled
UK mains tap water is treated and chlorinated, which makes it well suited to home storage. Fill clean food-grade containers straight from the cold tap, seal them, and the residual chlorine helps keep the water fresh for months. There is no need to add anything to ordinary treated tap water. Label each container with the date you filled it so you can track its age at a glance.
Bottled water is convenient and needs no preparation, but it is not indefinite. Manufacturers print a best-before date, typically one to two years out, chosen mainly because plastic can slowly affect taste over time rather than because the water spoils. Kept cool and sealed, it remains safe well beyond that date in practice, though flavour may dull. A mix of both, some stored tap water and a few packs of bottled, gives you flexibility.
Where to Keep It
Store water somewhere cool, dark and stable. Heat and sunlight encourage any stray bacteria to grow and degrade plastic over time, so keep containers away from windows and radiators. Good spots include an under-stairs cupboard, a cool utility room, a cellar or a shaded garage corner. Keep containers off bare concrete floors by resting them on a board or shelf, as plastic can pick up taints from the ground.
Crucially, keep drinking water well away from petrol, paint, solvents, cleaning products and pesticides. Vapours from these can pass through plastic and contaminate the water inside, which is a real risk in garages and sheds. Never store your emergency supply next to the mower fuel or the weedkiller. If space is tight, split the reserve across a couple of clean locations so a single leak or contamination cannot take out everything at once.
Rotation and Shelf Life
Stored tap water does not go off in the way food does, but it can develop a flat or musty taste and pick up traces from the container over time. The simple habit is to rotate every six months: empty the containers onto the garden or into the toilet cistern, rinse them, and refill with fresh tap water. Tie it to the clock changes in spring and autumn so it is easy to remember.
For bottled water, keep an eye on the best-before dates and use the oldest first, replacing as you go, so nothing sits forgotten for years. Storing your supply in a spot you pass regularly makes rotation far more likely to actually happen. A quick note on a calendar or phone reminder every six months turns a chore you forget into a two-minute routine.
Treating and Refreshing Stored Water
If you are ever unsure whether stored water is safe, treat it before drinking. The most reliable method is to bring it to a rolling boil for one minute, then let it cool; boiling kills bacteria, viruses and parasites. Water that looks cloudy should be filtered through a clean cloth or coffee filter first. Boiled water tastes flat, which you can fix by pouring it between two clean containers to add air back in.
Water purification tablets, based on chlorine dioxide or chlorine, are a compact backup and are sold at Go Outdoors and Amazon; follow the packet dosing and wait times exactly. Keep a strip in your emergency kit for treating water from uncertain sources. Discard any stored water that smells strongly, looks discoloured or has visible growth rather than trying to treat it, and clean the container thoroughly before reusing it.
Scaling Up and Emergency Sources at Home
For a family, think in terms of larger 20 or 25-litre containers alongside smaller ones the children can lift, and dedicate a shelf or corner to the reserve so it does not creep back into daily use. Building from three days towards a week is easy once the habit is set. Spreading storage across two rooms keeps weight manageable and reduces the chance of a single mishap draining your whole supply.
Remember that your home already holds water in an emergency. A typical hot water cylinder stores 100 to 200 litres, accessible via the drain valve once the supply is isolated and it has cooled. The cold-water tank in the loft holds more, and the cistern of your toilet, though not the bowl, is clean enough to use after treating. Turn off your incoming stopcock early in a contamination event to protect what is already in your pipes and tanks.
What to Do Next
Start small and build. This week, buy two or three ten-litre food-grade jerry cans, fill them from the cold tap, label them with today's date and store them somewhere cool and dark away from any chemicals. Add a few packs of bottled water and a strip of purification tablets to your kit. Set a recurring six-monthly reminder to rotate the stored tap water. With an afternoon's effort and a few pounds, you will have a calm, reliable buffer that means an interrupted supply becomes an inconvenience rather than a crisis.
