Fallout and food: is tap water and food in the cupboard safe?

First, what the UK guidance covers (and doesn't)

The UK's public advice on food and water after radiation comes from UKHSA's page What to do in a radiation emergency. It's written around accidents, such as a release from a nuclear power station or a transport incident. It doesn't mention nuclear weapons. The US government's Ready.gov page does cover a nuclear explosion, and its food and water advice points the same way. Where they differ, we say so.

This post is about food and water only. For what to do when a warning comes, see nuclear attack warning: what to do. For the bigger question of whether preparing is worth it, see is there any point preparing for a nuclear attack?.

Food and water indoors: safe

UKHSA is clear: food and drink that are already indoors, including tap water and food and drink in shops, will be safe to eat and drink. Ready.gov says the same: it's safe to eat and drink food that was inside a building.

So the tins, packets and bottled water in your cupboard are fine. So is what's in the fridge and freezer.

Tap water: keep drinking it unless told otherwise

UKHSA says mains tap water is unlikely to be affected immediately and is safe to drink unless you're told otherwise. If that changes, you'll be told through the usual channels: GOV.UK, radio, TV and your water company.

What you shouldn't drink, according to UKHSA:

• water collected from roofs or other surfaces
• water from shallow wells
• surface water, such as rain collected on a tarpaulin

This matters for anyone who uses water butts or private supplies. If your plan includes collecting rainwater, that's one of the first things to stop after a release.

Food and drink that were outside

Ready.gov gives the clearest advice here:

• Sealed containers (tins, bottles, sealed packets) that were outside are safe once you wipe them with a damp towel or cloth. Put the used cloth in a sealed plastic bag, away from people and pets.
• Unsealed food that was outside may be contaminated.
• Anything left outdoors and uncovered, food or drink, shouldn't be eaten until the authorities say it's safe.

Garden, allotment and foraged food: wait

This is the question people ask most on UK forums. The official answer is to wait:

• UKHSA says you'll get further advice on any food stored outside, including food you've grown yourself, and that guidance on home-grown produce, such as allotment fruit and vegetables, may be issued for the affected area.
• Ready.gov says don't eat food from your garden until authorities say it's safe.
• UKHSA's nuclear emergencies page explains why: radioactive material that lands on soil or grass can get into food through crops and animals. It names milk as a food that may need to be banned.

We didn't find official UK advice on whether washing or peeling makes garden produce safe after fallout, so we don't suggest it. Follow the instruction for your area when it comes.

Who decides what's safe to eat

After an emergency, UKHSA says a wide range of food supplies and drinking water would be checked against permitted levels, and food over the limits can be banned from sale. UKHSA notes the limits are set very low, so food controls can cover a wide area.

The legal limits are set under the Food and Feed (Maximum Permitted Levels of Radioactive Contamination) Regulations (updated in 2019, SI 2019/701). In plain words: after a nuclear accident or radiological emergency, the Food Standards Agency (or Food Standards Scotland) alerts ministers in each nation, who can put limits on how much radioactivity food and animal feed may contain. The first set of emergency measures can last up to three months.

The FSA's role is in the regulations, but we didn't find a current FSA page for the public on food after a radiation emergency. UKHSA's pages are the main public advice.

Keeping dust off food and out of the house

From UKHSA's and Ready.gov's advice:

1. Close doors, windows and vents, and turn off fans, air conditioning and any heating that draws in outside air.
2. Keep food covered and in sealed containers or the fridge.
3. If you were outside, take off your outer clothes before going further into the house. UKHSA says this alone can remove around 90% of contamination. Bag the clothes and keep them away from people and pets.
4. Wash with soap or a mild shampoo; UKHSA says not to use conditioner, as it can bind contamination to hair. If you can't wash, Ready.gov says to wipe skin and hair with a clean wet cloth.
5. Bring pets in if they're outside when you're told to go in, but don't go out looking for them (UKHSA). Wash pets that were outside with shampoo or soap and water.

What to keep in, so you don't need to go out

The point of a home store, in this situation, is that you don't have to go out in the first day or two. Be Ready's 3-day list covers it:

• 3 litres of water per person per day for 3 days, in bottles or food-grade containers with lids
• food that needs no cooking, that you already eat
• medicines, a torch and a battery or wind-up radio

UKHSA says most people would be asked to stay in for one to two days, possibly longer. Sweden's brochure says radiation levels drop sharply after a couple of days.

For quantities, see how much water to store in a small flat and the 7-day no-cook food box.

What we don't know, said plainly

• UK advice is written for accidents. UKHSA's food and water advice doesn't mention weapons. The physics of fallout settling on surfaces is the same, and US advice for an explosion agrees, but no UK page says so directly.
• No UK figures for how long garden produce would be off limits. It would depend on the release and the area, and officials would tell you.
• Iodine tablets don't make food safe. They protect only the thyroid, and UKHSA says to take them only when officials tell you. See our iodine tablets post.

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Related guides

• Radiation emergency in the UK: what official advice says (go in, stay in, tune in)
• Emergency food stockpile list: a calm UK list for 3 days, then 2 weeks
• Emergency water at home: how much to store and how
• Worried about war? How UK households can prepare — calmly

Free tools

• Emergency supplies calculator (water and food for your household)

We're an independent UK site, not the government. We check guides against official sources and link to them. In an emergency call 999.

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