How Long Should You Wash Your Hands?

Wash your hands for at least 20 seconds, with soap and clean running water. That is the figure the UK's public health guidance keeps returning to, and it is the one to remember: 20 seconds of scrubbing, then rinse well and dry thoroughly¹. Soap and water are the first choice. Hand sanitiser is the fallback for when soap and water are not immediately available, and only for hands that are not visibly dirty¹.

The length matters because it is the time it takes to cover the whole hand properly: the backs, between the fingers and under the nails, not just the palms. But when you wash matters just as much as how long. Get the moments right and you cut the spread of the infections that cause food poisoning and stomach bugs.

This page sets out the 20 second rule, the moments that matter most, what to do when the taps are off or you are out, and how to teach children to do it well. It is written for an ordinary household with no medical background, and it sticks to what official UK guidance says.

Wash for at least 20 seconds, and do it properly

Twenty seconds is the minimum, and the guidance is consistent across the UK's preparedness and health sources. The Prepare campaign, the government's public preparedness site, says to wash regularly with soap and clean running water for at least 20 seconds¹. West Yorkshire Prepared gives the same figure and adds the fallback: hand sanitiser if soap and water are not available².

The method is what fills those 20 seconds. NHS inform's food safety guidance sets it out step by step: wet your hands and apply soap, rub your hands together to make a lather, scrub the backs of your hands, between your fingers and under your nails, rinse well with warm water, and dry thoroughly using a clean towel³. It puts the scrubbing time at 20 seconds before rinsing³.

A common mistake is to rinse too soon, or to skip drying. Drying thoroughly with a clean towel is part of the method, not an optional extra³. Another is to wash only the palms. The backs of the hands, the spaces between the fingers and under the nails are where dirt and germs collect, which is why the guidance names them³.

When to wash: the moments that matter most

The 20 second rule only helps if you apply it at the right moments. Official guidance groups them into a short list, and it is worth learning because it covers most of the day.

• Before you prepare, cook or eat food, and before serving it³.
• After handling raw food, such as raw meat, uncooked eggs and unwashed fruit and vegetables³.
• After using the toilet, and after changing a nappy or helping a child⁶.
• After coughing, sneezing or blowing your nose⁸.
• After touching the bin, or handling animals including pets³.
• After contact with someone who is ill, and before handling food for others⁵.

Derbyshire's flu guidance puts the key times plainly: after coughing and sneezing, before preparing food and eating, and after using the toilet⁸. Shropshire's food poisoning guidance says to wash your hands after contact with a sick person and before handling food, and not to share towels or face cloths with them⁷.

If someone in the house has diarrhoea and vomiting, the advice steps up. Wash your hands regularly, every time you use the toilet, and before eating or drinking, and disinfect door handles, toilet flush levers, kettle and fridge door handles regularly throughout the day¹⁰. That is because the viruses that cause stomach bugs spread easily from hands to surfaces and back again.

Hand sanitiser when soap and water are not available

Hand sanitiser is useful, but it is a fallback, not a replacement. The Prepare campaign says that if you do not have immediate access to soap and water, hand sanitiser can be used to clean hands that are not visibly dirty¹. It then adds an important limit: hand sanitiser does not effectively remove all types of disease-causing organisms, such as norovirus, so soap and water should be used to wash hands wherever possible¹. That is the sentence to remember. For norovirus, the stomach bug that spreads quickly through households, soap and water is the one that works.

Devon's public health team gives the same fallback: if you do not have immediate access to soap and water, use alcohol-based hand rub if available¹¹. Northern Ireland's nidirect guidance, in its advice for water supply cut-offs, recommends alcohol-based hand sanitiser for cleaning your hands before touching food¹².

The pattern is consistent: soap and water first, sanitiser when you cannot get to it, and never rely on sanitiser for norovirus¹.

Washing hands when the water is off

A water cut, a flood or a burst pipe can leave you without running water for a time, and handwashing still matters. The Prepare campaign's water supply guidance gives a practical method: fill a large clean bowl, such as a washing up bowl, with water and add some soap or a household disinfectant¹³. The same guidance adds a reason to be careful with water: keeping water usage to a minimum will prolong alternative sources of water⁴.

Food Standards Scotland's flooding advice offers a simpler fallback for food handling: if you have no running water, you can use alcohol gels or wet wipes to clean hands before handling food¹⁴. Perth and Kinross's flooding checklist says to wash your hands regularly with soap and warm clean water, or use wet wipes if there is no clean water available, and to keep cuts clean and use waterproof plasters¹⁵. Public Health Wales adds that children's hands should be washed frequently and always before meals¹⁶.

If you are storing water for an outage, the same discipline applies: keep a bowl and soap where you can reach them, and use the bowl method rather than letting a tap run. Turning off the tap while you wash your hands can save up to 6 litres of water per minute, according to the Prepare campaign's drought guidance¹⁷. That matters most when supply is short.

Handwashing during an outbreak or pandemic

When an infectious disease is spreading, handwashing moves from routine to central. Surrey's emergency planning guidance for pandemics says to practise good hygiene habits, always wash your hands thoroughly, and cough or sneeze into disposable tissues¹⁸. The West Midlands community risk register, published in December 2023, lists regular handwashing with soap and warm water among the practical steps households can take, alongside vaccines and keeping personal stocks of over-the-counter medication¹⁹.

The UK National Risk Register, published in 2017, explains why: flu germs can live on some surfaces for hours, and if you have flu you can protect others by carrying tissues, catching coughs and sneezes, binning the tissue, and washing your hands with soap and water or using a sanitiser gel²⁰. Westminster's household preparedness guidance, from 2014, gives the same basic advice for pandemic flu: wash your hands frequently with soap and water to reduce the spread of the virus from your hands to your face or to other people²¹.

The pattern across all of these is the same, whatever the outbreak: wash hands frequently, use soap and water, and cover coughs and sneezes. The advice does not change with the name of the virus. For more on how households should prepare for an outbreak, see Pandemics: How the UK Plans and What Households Should Do and Stopping Infections Spreading at Home: Hands, Cleaning and Fresh Air.

Why handwashing stops food poisoning and infections spreading

Handwashing is not a small habit. Shropshire's environmental health team puts it plainly: handwashing is the single most effective way to stop the spread of infection⁵. That is the sentence that explains why the 20 second rule appears in guidance on flu, norovirus, food safety, flooding and pandemics alike.

The mechanism is simple. Germs on your hands move to your mouth, to food, or to surfaces that other people touch. Washing removes them. The guidance on food poisoning makes the link explicit: hand washing with anti-bacterial soap, and keeping work surfaces and utensils clean and disinfecting them, are the core prevention measures⁵. When someone is ill at home, washing your hands after contact with them and before handling food is one of the main ways to stop it spreading to the rest of the household⁵.

Food safety guidance adds a specific warning about raw meat. Always clean surfaces, utensils, plates and hands thoroughly after they have touched raw or thawing meat, to stop bacteria spreading around the kitchen⁹. That is why the key moments list includes handling raw food: it is not just about your own hands, but about everything they touch next.

The same logic applies to children. Public Health Wales advises washing children's hands frequently and always before meals¹⁶, and the NHS sepsis guidance says to wash your hands regularly and teach children how to wash their hands well²². Children pick up and pass on infections easily, so the habit is worth teaching early. For more on keeping a household safe when someone is ill, see Staying at Home When Ill: Keeping Your Household and Others Safe and Norovirus: Symptoms, How Long It Lasts and Stopping It Spreading.