What a boil-water advisory means
A boil-water advisory is an official announcement telling you to boil your drinking water before use. It means there's a risk that disease-causing microorganisms (bacteria, viruses, or parasites) may be in your tap water. Boiling kills these organisms and makes the water safe to drink.
Always follow instructions from your local health authority or water utility. They will tell you when the advisory is in effect and when it's been lifted.
Immediate steps
- Stop drinking tap water unless it has been boiled
- Use bottled water instead, or boil tap water before use
- Listen for updates from local officials about when the advisory ends
How to boil water safely
- Bring water to a rolling boil (vigorous boil where bubbles appear at the centre)
- Keep it boiling:
- 1 minute at sea level
- At least 2 minutes if you're above 2,000 metres elevation
- Let it cool before drinking or storing
- Boil all water used for:
- Drinking
- Food preparation and cooking
- Beverages (tea, coffee, juice made with water)
- Ice cubes
- Washing fresh produce
- Tooth brushing and rinsing
Boiling does NOT remove
- Sediment or cloudiness
- Chemicals or heavy metals
- Some pesticides
If your water is cloudy or discoloured, filter it through a clean cloth first, then boil it.
When the advisory ends
Local officials will announce when the boil-water advisory is lifted. You'll usually hear this through:
- Local news (TV, radio, online)
- Your water utility's website or phone line
- Municipal social media or alerts
- 211 emergency helpline
Do not assume the advisory is over without official confirmation.
For specific situations
- Bottles and baby formula: Use boiled water if the advisory affects your area
- Pet water: Boil water for pets too
- Washing dishes: If you prefer, boil the rinse water (but regular dishwashing with hot water is usually safe)
See also: Purify water by boiling or bleach for other situations when tap water is unsafe.