Stay safe during a Boil Water notice | The Water Services Authority

When a Boil Water notice is in place, follow the advice on this page to make sure you’re safe from any microscopic germs in the water.

Common reasons for a Boil Water notice include E. coli being found in a water sample, problems with the water treatment system or physical signs of contamination, like a dead bird in a water tank.

How to make water safe

Boil water or use commercially bottled water if you can. These are the best ways to stay safe when a Boil Water notice is in place for water you normally use.

If you can’t boil water or get bottled water, you can use water purification tablets or bleach instead.

Boiling

Boiling water is the easiest and most effective way to disinfect water. Boiling kills any microscopic germs in water.

Boil water from your tap in an electric jug/kettle until it turns off automatically, or in a pot on the stove until it comes to a rolling boil.

Use boiled water hot or allow it to cool in a covered container and keep it in the fridge or somewhere cool.

Commercially bottled water

Commercially bottled water is safe to use for every purpose.

You can buy bottled water at your local shops, or your water supplier might provide some.

Keep bottled water in its original container and don’t open it until you need to use it.

Water carriers (tankers)

Your water supplier might use a water carrier (tanker) to provide safe drinking water.

Use clean bottles to collect water from the carrier. If you don’t have water containers in your emergency kit, you can use clean soft drink bottles.

Purification tablets

If you can’t boil your water or use commercially bottled water, you can use purification tablets to disinfect your water.

Follow the manufacturer's instructions for how to use these.

Purification tablets don’t work on a type of germ called protozoa. This is why boiled or bottled water are recommended. Giardia and cryptosporidium are the two most common dangerous protozoa that can be found in water. They are parasites that can make some people very sick with diarrhoea, stomach cramps and nausea or vomiting.

Bleach

If it’s not possible to boil water or get bottled water, disinfecting water by adding bleach is effective for killing most germs. 

Bleach does not work on a type of germ called protozoa. Giardia and cryptosporidium are the two most common dangerous protozoa that can be found in water. They are parasites that can make some people very sick with diarrhoea, stomach cramps and nausea or vomiting.

Use the right type of bleach

Only use plain, unscented bleach.

Some bleaches contain added chemicals that can make you sick or make water undrinkable. 

Do not use bleach that contains:

cleaning chemicals (surfactants), which make the bleach foam or bubble when it is shaken or mixed

added scent or perfume

any other additives.

Words like “thick”, “gel”, “foam” or “cleaner” on the label normally mean there are additives in the bleach and it is not safe to use to disinfect water.

If the label is not clear about what has been added to the bleach, do not use the product to disinfect water.

Disinfect water with plain, unscented bleach

To disinfect the water, add 5 drops of bleach to 1 litre of water or 1/2 teaspoon to 10 litres of water. Stir and leave the water to stand for 30 minutes before drinking.

If your water changes colour when you add bleach

Water sourced from underground contains minerals. Some minerals can react with bleach and change the colour of water. If this happens, the water is not dangerous to drink.

If you don't like the chlorine taste of bleach 

You can store water disinfected with bleach uncovered in the fridge to improve the taste. Chilled water will taste better and lose that chlorine smell.

You can also improve the taste by shaking the water vigorously or pouring it between containers.

Using boiled and tap water

When a Boil Water notice is in place, you should boil any water that will be swallowed or near someone’s mouth, e.g. to drink, mix baby formula and brush teeth.

Use boiled or bottled water, or water disinfected with bleach

You can safely do the following using boiled, bottled or disinfected water.

Drink	Use boiled, bottled or disinfected water to drink, mix soft drinks, make tea and coffee.
Mix baby formula	Use cooled boiled water to mix infant formula. Wash and sterilise bottles and teats in boiling water. If you are breastfeeding, continue as usual.
Brush teeth and soak dentures	If you accidentally use tap water to brush your teeth or soak dentures, clean your toothbrush or dentures in boiling water.
Prepare food	Food that will not be cooked should be prepared using treated water, e.g. salad. If food will be brought to a boil as part of cooking, you do not need to treat water first, e.g. pasta.
Hand wash dishes	Dishes can be washed by hand using boiled water and detergent. Make sure the water is at a safe temperature before putting your hands in it. You can also use hot tap water and detergent, then rinse the dishes in boiled water. If you can’t boil water, wash dishes with tap water and detergent, then rinse them in bleach solution (1/4 cup of plain unscented household bleach per 10 litres of water). Allow dishes to air dry completely.
Make ice	Ice makers connected to the water supply should not be used. Use boiled, bottled or treated water to make ice in the freezer. Throw out any ice that might be contaminated.
Give to your pets	If the water is not safe for you to drink, it is not safe for your animals. Give animals boiled, bottled or disinfected water.
Water fruit and vegetable plants	Water fruit and vegetable plants in your garden with boiled, bottled or disinfected water. Leave boiled water to cool before watering plants.

Use tap water with caution

You can safely do the following using tap water if you are careful.

Shower/bathe	Adults and older children can still shower and bathe normally. Be careful not to accidentally swallow any tap water when bathing. If you have recent surgical wounds or a chronic illness, use boiled or bottled water for bathing. Young children should be sponge-bathed because they are more likely to swallow bath water.
Use the dishwasher	You can use the dishwasher with a hot wash cycle plus a drying cycle. Check the user manual if you don’t know how. You can find these online. If your dishwasher can’t do a hot wash cycle plus a drying cycle, handwash dishes with treated water.
Do laundry	Continue to do laundry the way you usually do.
Wash hands	Wash hands with soap and water. Dry your hands well after washing.
Clean with	Clean food preparation and cooking surfaces with a normal cleaning product. Allow the surface to dry before use.
Water houseplants	Water houseplants and non-food plants as normal. Don’t use tap water on your vegetable garden or fruit trees.
Shaving	You can shave as normal.

What to do when a Boil Water notice is lifted

When a Boil Water notice is lifted, there a few things to do before it is safe to use your water normally again. If you are on a trickle-feed supply or have a water tank, you need to manage your tank first.

Manage water tanks and trickle-feed supplies

Trickle-feed supplies and water tanks need to be managed first before flushing taps and appliances. There are three options for managing your stored water.

The best option is to drain your tank, rinse it with safe water and then refill it. This makes sure there are no bugs or microorganisms still in the tank.
Disinfect the water in your tank using additive-free bleach. The amount of bleach to use depends on the product. For bleach with 5% chlorine, use 33ml per 500L of water. Bleach does not work on a type of microscopic bug called protozoa. Giardia and cryptosporidium are the two of the most common dangerous protozoa found in water. They are parasites that can make some people very sick with diarrhoea, stomach cramps, and nausea or vomiting. Protozoa will remain in water even after bleach is added.
You can continue to boil water until your tank has completely refreshed. You can find out when your water has been completely refreshed by having it tested by an accredited lab.

Find an accredited lab near you outbound

Flush taps and appliances

Before it is safe to use water from your tap or tanks, you will need to:  

run all cold taps for five minutes to flush out any contaminated water  
run clean water through appliances like coffee machines, water dispensers and ice machines to make sure you don’t accidentally use contaminated water 
empty and refill any header tanks used for drinking water 
maintain any water filters according to the manufacturer's advice.

You do not need to do anything to hot water tanks. These are already safe to use.

Test water for peace of mind

Having a sample of tap water tested by an accredited laboratory is the best way to ensure the water is free from harmful germs and safe to use.

Find an accredited laboratory near you. outbound