How Much Drinking Water to Store per Person

Store at least 3 litres of bottled water per person per day, for at least 3 days. That is the core figure repeated across official UK guidance, from the national "Be Ready" checklist to local council emergency pages¹. For a family of four, that means 36 litres of drinking water set aside before anything goes wrong.

That 3 litres covers drinking only. Official guidance is clear that more would be needed for other tasks such as cooking and washing², and one widely used planning figure puts the comfortable total at 10 litres per person per day once basic cooking and hygiene are included³. If anyone in your household is a baby, a nursing mother, unwell, older, or a pet, they need extra on top of their share.

This page works through the numbers so you can settle on a total for your own household: where the figures come from, why they differ, what to add for special needs, how long supplies should last, and what help exists if a cut outlasts your store.

The headline figure: 3 litres per person per day, for 3 days

The national "Be Ready" campaign tells households to keep at least 3 days' worth of bottled water, at 3 litres per person per day¹. Its checklist repeats the same instruction: bottled water for 3 days, 3 litres per person per day for drinking, with more needed for other tasks such as cooking and washing². The Household Emergency Plan template that accompanies the campaign states it as "Bottled water (3 litres per person per day for at least 3 days)"⁸.

Local authorities give the same advice. Birmingham City Council tells residents to keep water for cooking and washing at at least 3 litres per person per day, and drinking water at at least 2 litres per person per day⁹. Lancashire Prepared's emergency pack list includes enough food and bottled drinking water to last three days¹⁰, and Renfrewshire Council advises keeping supplies that can meet essential household needs for at least 3 days¹¹. Argyll and Bute Council advises at least three days' supply of food, bottled water and other essentials, including medicines and tinned and dry foods that store safely without electricity¹².

Working out your household total is simple multiplication:

To find your household's 3-day total, take the daily figure for each person and set aside that amount for each of the 3 days. A two-person household drinking only needs twice the single-person daily amount, repeated across the 3 days; the same arithmetic applies to the 10 litre comfort rate if you want cooking and hygiene covered as well.

The drinking-only column uses the 3 litres per person per day figure¹; the wider column uses the 10 litres per person per day comfort figure³. Both are 3-day stores, the duration official guidance most commonly asks for². For guidance on what to put the water in, see containers and jerrycans and storing tap water safely.

Why the figures differ: 2.5 litres, 3 litres, 10 litres and a gallon a day

You will meet several numbers if you read around, and they are not in conflict so much as answering different questions.

The smallest figures describe survival needs. Greater Manchester's resilience guidance states that a minimum of 2.5 to 3 litres of drinking water per person per day is recommended for survival, and that 10 litres per person per day will make you more comfortable by also providing for basic cooking and hygiene needs³. North Devon Council attributes the 2.5 to 3 litre survival minimum to the World Health Organisation¹³. Dumfries and Galloway Council's household plan asks for 2.5 litres of bottled water per person for each day¹⁴, and Denbighshire Council similarly advises storing at least 2.5 litres per person per day to cover sanitary purposes and possibly cooking⁶.

The 3 litre figure in the national campaign sits at the top of that survival range and adds a margin. It is also close to what a healthy adult actually drinks: the Food Standards Agency advises that the average adult should drink 1.5 to 2 litres of water in a typical day, about 6 to 8 250 ml glasses¹⁵, and South East Coast Ambulance Service NHS Foundation Trust notes the normal recommended daily intake of fluid is 2.5 litres or 8 glasses per day¹⁶. Three litres gives headroom for a hot day, extra activity, or a child spilling theirs.

The larger figures cover more than drinking. Ten litres per person per day is the planning figure for basic cooking and hygiene³. In Wales, the flood response framework goes further: if an interruption of mains water exceeds 5 days following the declaration of a major incident, the allowance increases to 20 litres per person per day¹⁸.

The gallon figure comes from a different tradition. Bradford Council's flood pack advises storing one gallon (eight pints) of water per person per day, split as four pints for drinking and four pints for food preparation and sanitation⁴. Because it covers drinking plus some cooking and washing in a single number, it sits between the drinking-only and full-comfort figures. It is a reasonable single rule of thumb if you want one amount that covers a little of everything.

Extra water for cooking, washing and hygiene

Drinking is the priority, but a supply interruption that lasts more than a few hours starts to bite in the kitchen and bathroom too. North Hertfordshire District Council spells it out: 10 litres per person per day would provide for basic cooking and hygiene needs¹⁷, matching the Greater Manchester figure³.

What does that look like in practice? Water for rehydrating tinned or dried food, for rinsing plates and utensils, for a strip wash at the sink, for brushing teeth, and for a small amount of flushing. It is worth knowing that a family of four generates around 570 litres of wastewater per day in normal life¹⁹, which shows how far an emergency store falls short of ordinary use: 10 litres per person is about keeping clean and fed, not about showers and laundry.

If you want to stretch your store, plan to use the water already in your home. The pipes, cistern and hot water cylinder hold usable water in most houses, and there are safe ways to flush the toilet and wash with very little. Guidance on heating and cooking without mains power covers preparing food when the hob is off too.

Babies, medical needs and people who need more

Several groups need more than the standard allowance, and official guidance names them directly.

Children, nursing mothers and people who are unwell will need more⁴. Denbighshire Council makes the same point: a normally active person needs at least two litres of water daily just for drinking, and children, nursing mothers and ill people need more⁶. In hot weather, fluid needs rise further¹⁶.

Babies bring a specific issue: formula. Additional water might be needed to make up baby formula, for medical devices and for pets³, and North Hertfordshire District Council gives the same list¹⁷. The national campaign advises that in rare circumstances, such as when drinking water is unavailable or has been contaminated, you can use still bottled water to make up formula feeds, but bottled water is not usually recommended for this because it is not sterile and may contain too much salt (sodium) or sulphate¹. If you have no tap water, ready-made or ready-to-feed formula is the safest option¹. There is a full guide at babies and formula feeds, and for medical equipment such as home dialysis, see home dialysis and medical needs.

For disabled people and carers, the national campaign's easy-read guidance recommends having an extra supply of food and bottled water²². If someone in your household depends on electricity or water for medical reasons, the extra help page sets out the wider arrangements.

Water for pets

Pets need their own allocation, and official guidance is consistent that it should be part of your store rather than an afterthought.

Birmingham City Council advises making sure you have at least 3 days' supply of pet food and water, stored in waterproof containers, if advised to stay indoors⁵. Wiltshire and Swindon Prepared's pet kit list asks for a couple of bottles of water and a bowl to keep it in²³, plus a small extra supply of any required medicine in a waterproof cover²³. Slough Borough Council goes further and suggests a week's worth of food, water, medication, cat litter or any other supplies your pet needs on a regular basis²⁴. Buckinghamshire Council's pet emergency kit list includes several days' supply of food in an airtight, waterproof container, a water bowl and several days' supply of water, an extra supply of regular medicine, a first aid kit, a collar with ID tag and leash, a carrier, and a picture of you and your pet together²⁵. Lincolnshire's advice adds pet medications and medical records in a waterproof container²⁶.

A practical approach: count each pet as roughly another person's drinking ration, stored separately in sealed bottles with a dedicated bowl, and keep any pet medicine with it in a waterproof container. The pets and animals page covers the wider plan.

How many days should your supplies last?

Three days is the figure almost every official source settles on, but it is a minimum, not a maximum.

Birmingham City Council tells residents to keep enough supplies to meet their household's needs for at least 72 hours⁹. Renfrewshire Council says at least 3 days¹¹, Argyll and Bute at least three days¹², and the national campaign's checklist is built around 3 days². The emergency kit page pulls the whole list together.

Why three? Because most interruptions are shorter than that, but the worst ones are not. After the 2018 freeze-thaw, Ofwat reported that most water companies were able to restore supply to most customers within 12 hours, but over 60,000 customers were without supply for over 12 hours, and over 36,000 of those were impacted for more than 24 hours²⁷. The London Risk Register's planning assumption for a severe water supply scenario is starker: up to 350,000 people affected for between 24 hours and two weeks⁷.

Real events show the spread. In December 2022, a freeze-thaw in West Wales left approximately 12,000 properties supplied from six reservoirs without water, with some customers off supply for up to seven days and the majority restored within four days²⁸. During that incident bottled water was delivered to over 3,000 customers²⁸. A 3-day store covers the common case comfortably and buys time in the rare long one; if you have the space, a week's store, as Slough suggests for pets²⁴, covers more of the tail.

Storing bottled water: keep it fresh and replace it every six months

Bottled water does not keep indefinitely in an emergency store. Denbighshire Council's emergency supplies guidance is direct: bottled water will have to be replaced every six months⁶. The national power outage guidance adds a simpler habit: hold a small amount of bottled water in your home, but make sure it is not past its expiry date²⁹.

The reason is quality as much as date. Official guidance notes that the bacteria count in bottled water is much higher than in tap water, varies according to the temperature at which it is stored, and can be very high if someone has drunk the water from the bottle³⁰. So three rules follow:

• Store bottles somewhere cool and dark, not next to a boiler or in a hot loft.
• Keep bottles sealed until you need them; never drink from and then re-store an emergency bottle.
• Rotate the stock: drink it and replace it every six months⁶.

For how to store water beyond shop-bought bottles, including tap water in your own containers, see storing tap water safely, storage tanks and the home drinking supply storage checklist. The narrow guide on how to store bottled water goes into detail on where and how.

When the tap stops: what your water company must provide

If the mains fails, you are not on your own. Water companies have duties to provide alternative supplies, and the scale is set by planning thresholds. In the December 2022 West Wales incident, the company's calculations were based on providing 10 litres per person per day for the first 24 hours and 3 days, and 20 litres per person per day after 5 days²⁸. For rural locations in that company's area, the threshold for providing alternative supplies was 10,000 customers within the first 24 hours and 20,000 customers within the first 3 days of an incident being declared²⁸.

In practice, alternative supply means bottled water stations and deliveries. Research into recent incidents found that people typically received two lots of 6x2 litre packs of water at stations, which were typically loaded into car boots by staff members³¹. That is a useful amount but not a household's full 3-day store at the 3 litre per person per day rate, so expect to return. The bottled water stations page explains where they are set up, and how water companies respond to a major incident explains the machinery behind it.

One caution from the same research: in the South East Water disruptions of late 2025 and January 2026, significant minorities of customers were unclear how to access safe drinking water³¹. Knowing in advance how your company will contact you matters; see incident alerts and how to check if there is an outage in your area.

The Priority Services Register: bottled water delivered to your door

If someone in your household is vulnerable, register with your water company's Priority Services Register before anything goes wrong. Official drought guidance states that vulnerable consumers should contact their water company to register on their Priority Services Register so they can receive extra help and support, for example the delivery of bottled water²¹.

The register works during incidents. In the December 2022 event, the water company stated that customers registered for bottled water for non-medical reasons were intended to receive bottled water after 4 hours where possible²⁸. Registration is free and is done directly with your water company; the narrow guide on how to get bottled water delivered if you are vulnerable walks through it, and the extra help page covers the wider support available to older, disabled and medically dependent households.

Filtering instead of, or as well as, storing

Storing every litre is not the only approach. A filter jerrycan lets you treat water you collect, which suits households with space limits but a stream, pond or rainwater nearby. The maker states that the LifeSaver Jerrycan Starter Pack filters up to 20,000 litres³², and a customer review on the maker's page reports using it all through the summer to filter lake, pond and rain water for up to 8 people, and through winter to filter tap water³².

Treat a filter as a complement to a stored supply, not a replacement. It depends on there being water to filter and on the filter being maintained, and it does nothing for cooking and hygiene volumes. If this route interests you, the emergency filters page compares the types, what each filter removes explains the technologies, and there are product pages for the LifeSaver Jerrycan and its stablemates. For making any collected water safe by other means, see boiling and purification tablets.

A worked example: a family of four

To make it concrete, take two adults, one child, a baby and a dog.

• Drinking water for the three who drink: 3 litres each per day for 3 days¹.
• Cooking and hygiene at the comfort rate: 10 litres per person per day³; a more modest store of the drinking total plus a few extra litres for cooking is a reasonable start.
• Baby: plan on ready-to-feed formula as the safest option if tap water is off¹, with a small extra allowance of water for washing bottles.
• Dog: a couple of bottles of water and a bowl²³, or 3 days' pet food and water in waterproof containers⁵.
• Replace the bottled water every six months⁶.

That household's realistic minimum is drinking water at 3 litres per person per day for each of the 3 days, plus extra litres for cooking, plus formula, plus pet supplies, plus whatever they can draw from the pipes and cistern in an emergency. The supply interruption checklist turns this into a tick-list.