What to Do If You Get a Boil Water Notice

A boil water notice means the water coming out of your tap may no longer be safe to drink. Until your water company tells you otherwise, boil tap water before you drink it, brush your teeth with it, make ice cubes with it, prepare food with it, clean feeding equipment with it or give it to pets¹. Bring it to the boil, let it cool, and keep it covered.

The notice is usually a precaution, issued while further water quality tests are carried out, and it will come to you in writing with instructions on what to do². It is normally caused by weather emergencies or engineering works¹. You do not need to boil water for washing or flushing, but you do need to be careful with anything that goes in a mouth, including a baby's bottle.

This page sets out what to boil and what to leave, how to boil and cool water safely, what to do about baby feeds, pets and open wounds, and how the notice will end. If you want the wider picture on storing and treating water at home, start with Water in an Emergency: A Household Guide.

What a boil water notice means

A boil water notice tells you that the water in your tap might contain bacteria, viruses or parasites which could be harmful to your health¹. It is not a statement that the water is definitely contaminated. Wessex Water describes it as a precautionary measure to ensure your safety while further water quality tests are carried out, issued in writing and explaining what to do². Dŵr Cymru Welsh Water says notices are issued when monitoring checks show the water supply may have fallen below usual high standards⁶.

The cause is usually a weather emergency or engineering works¹. That matters for how you read the notice: a burst main or a treatment failure can let contamination into the pipes, and the company cannot yet prove the water is clean, so it asks everyone in the affected area to boil as a precaution until sampling confirms the supply is back to standard.

Not every notice is a boil notice. Water suppliers send different kinds of notice for different circumstances, and they are not interchangeable⁷. Southern Water lists five that could be issued: boil your tap water before use; do not use tap water for drinking or cooking; do not use tap water for drinking, cooking or washing; do not use tap water; and use tap water as normal⁸. If your notice says "do not drink" or "do not use", boiling is not the answer, and you should follow that notice instead. Our page on Do Not Drink and Do Not Use Notices explains the difference.

A boil notice is not a compensation event in itself. The Consumer Council for Water says you are not entitled to compensation simply because your area is subject to a boil water notice, though some compensation might apply if you are without water⁹.

Boil your water for drinking, food, baby feeds, teeth and ice

The list of what to boil is longer than most people expect, because it covers anything that goes into a mouth. The Drinking Water Inspectorate's advice is to boil water before you drink it, use it to brush your teeth, make ice cubes, prepare food, clean feeding equipment or give it to pets¹. Public Health Wales puts it plainly: use only boiled water for drinking, brushing teeth and preparing food¹⁰.

That means:

• Drinking water and cold drinks, including squash and any water kept in a jug.
• Ice cubes, which are frozen tap water.
• Brushing teeth, and rinsing after brushing.
• Food preparation, particularly food eaten uncooked such as salads and fruit⁴.
• Baby feeds and feeding equipment, which must never be prepared with unboiled water⁵.
• Pet drinking water, because pets may be at risk too³.

If you are in any doubt during a flood or an incident, the same rule applies more widely: boil all water intended for drinking, brushing teeth, washing food and cooking¹¹. Nottinghamshire County Council's advice for when water is needed urgently and you are unsure about its quality is either to boil your water before using it, or to use bottled water¹³.

How long to boil, and how to cool and store it

You do not need to boil water for minutes on end. Anglian Water's boil notice guidance is to simply bring the water to the boil and use or cool as required, and states that prolonged boiling is not necessary³. Bring it up to a rolling boil, then turn the heat off.

Cooling needs a little care, because boiled water can pick up contamination again as it cools. Government flood recovery guidance advises using it as soon as possible for that reason⁷. Once cooled, store it in a covered container in the fridge. Argyll and Bute Council, giving advice for private supplies, says water needs only to be brought to the boil and can then be stored in a covered container in the fridge for up to 48 hours⁴. United Utilities, writing about chlorine and taste rather than boil notices, advises storing cooled boiled water in a covered container in the fridge and discarding it if not used within 24 hours¹⁵. The two figures differ; if in doubt, use it sooner.

For more on the method itself, including what boiling does and does not kill, see Boiling to Kill Germs: How to Do It Properly. If you are storing cooled boiled water and wondering how long it keeps, How Long Can You Keep Boiled Water in the Fridge? goes into it further.

Baby feeds, open wounds and kitchen surfaces

Three groups need more than the basic rule.

Babies. The instruction is absolute: do not prepare baby feeds with water without boiling it first⁵. That covers the water used to make up formula and the water used to clean and sterilise feeding equipment¹. If you cannot boil water, bottled water is the alternative, and our page on Babies and Formula Feeds When the Supply Is Off or Unsafe sets out how to manage.

Open wounds. Anglian Water recommends that cooled boiled water be used for bathing open wounds while a boil notice is in place³.

Kitchen surfaces. The same guidance recommends using water that has been boiled and then cooled for cleaning down food preparation surfaces³. This is about the surfaces where food is handled, not about general household cleaning.

For food and drink businesses, the advice is that all water for drinking and food preparation should be brought to the boil and cooled as necessary, that bottled water may be used as normal, and that fizzy drinks dispensers should not be used unless adapted to use sources other than tap water³.

Who issues the notice, and how you will hear about it

For a mains supply, the water company issues the notice to consumers in the affected area, instructing them to boil their water before use¹. For a private water supply, the notice comes from your local authority¹.

Water companies use several routes to reach you. Dŵr Cymru Welsh Water says a boiled water notice or do not drink notice will be issued directly to affected customers through text messaging, email and post, and will also appear on the company website homepage, social media channels and local press¹⁶. Northumbrian Water says boil water or do not use water advice will be sent by text message, letterbox notice, social media and local press¹⁷. If your property is in the affected area, you will be contacted directly by text and/or letter⁵.

That makes one preparation worth doing now: check that your water company holds a current mobile number and email address for your household, so a notice reaches you quickly rather than sitting in a letterbox. Our page on How Will My Water Company Contact Me in an Incident? covers this.

Private water supplies and boil notices

If your water comes from a well, borehole or spring rather than the mains, the arrangements are different. Your local authority regulates the supply and issues any notice¹. If your water fails a test, you will be told what went wrong, you may need to boil water or stop using it, you will get advice on how to fix the issue, and you may receive a legal notice requiring improvements¹⁸.

Some private supply users are advised to boil routinely. Argyll and Bute Council recommends that people who are young, elderly, immune-compromised, or not used to normally consuming the water should always boil water used for drinking (including preparing cold drinks and ice), brushing teeth, and preparing food, particularly food eaten uncooked such as salads and fruit⁴. The same council advises that if you notice any changes to your supply, it is recommended that you boil the water before use, particularly for vulnerable groups¹⁹.

Flooding brings its own risk to private supplies. If you notice any changes to your supply, it is recommended that you boil the water before use, particularly for vulnerable groups such as the young, elderly, immune-compromised and those not used to normally consuming it²⁰. If your supply fails a test you will be told what went wrong, you may need to boil water or stop using it, you will get advice on how to fix the issue, and you may receive a legal notice to make improvements²¹. The Drinking Water Inspectorate's case studies show how this works in practice: in one case the owner of a supply issued boil water advice to all the properties and began an investigation²².

If you rely on a private supply, our page on Private Supplies: Wells, Boreholes and Springs explains testing, treatment and what your council does.

Washing, bathing and pets

A boil water notice is about water you consume, not water you wash in. You can wash and bathe as normal, with the exception of open wounds, where cooled boiled water is recommended³. Take care with hot water bottles: fill them with warm water, never boiling water, to prevent scalds or burns¹⁴, and if you are using boiled water for one, allow it to cool for at least five minutes before pouring²³.

Pets need thought. Anglian Water recommends that domestic pets are provided with cooled boiled water for drinking because they may be at risk too³. Fish keepers should not change the water in their fish tanks while the notice is in place³. Keep pet food and bottled water for pets in your household kit²⁴, and if flooding is involved, keep pets away from floodwater and prevent them drinking it⁷. Our page on Pets and Animals in an Emergency covers the wider preparations.

Bottled water instead, and when the notice ends

Bottled water is a sound substitute at any point during a notice. Anglian Water's guidance for food businesses states that bottled water may be used as normal³. If water is needed urgently and you are unsure about its quality, official flood guidance says either boil your water before using it, or use bottled water¹³. If there is no alternative, a water ampoule can be used²⁵. Bottled water is also the practical answer for anyone who cannot boil water safely, and for baby feeds when boiling is not possible.

The notice ends when your water company says it does. Dŵr Cymru Welsh Water says that if your property is in the affected area, it will contact you directly by text and/or letter⁵. Do not assume the notice has lifted because the water looks or tastes normal, and do not switch back to unboiled tap water for drinking, teeth or food until you have been told. When the supply is confirmed safe, run the taps as your company advises and follow any flushing instructions; our page on What to Do When Your Supply Comes Back On sets out the steps.

For a sense of how long these things last, the Consumer Council for Water's research into incident response records a boil water notice lasting 3 days in one incident²⁶. That is one example, not a rule: the length depends on the cause and on how quickly sampling confirms the supply is clean.

What to have ready before a notice arrives

You do not need much to get through a boil notice comfortably, but a few things make it easier. The government's Be Ready campaign advises households to think ahead about the emergencies most likely to affect them²⁷, and its checklist includes pet food and bottled water²⁴.

• A kettle you can rely on, and a lidded jug or container for cooling and storing boiled water in the fridge¹⁰.
• Bottled water, enough for drinking and for baby feeds if you have a baby¹³.
• Pet food and bottled water for pets²⁴.
• A way to hear from your water company: a current mobile number and email on your account¹⁶.
• A note of your water company's incident page, so you can check updates¹⁶.

If you want a printable version of the steps on this page, use the Boil Notice Checklist for Your Home. For storing water more generally, see How Much Drinking Water to Store per Person and Storing Tap Water Safely at Home.