Boil Water Advisory
A public health notice requiring residents to boil tap water before drinking or cooking — issued when water may be contaminated with disease-causing organisms.
How It Works
Boil water advisories are issued when: water pressure drops below a safe level (allowing contaminants to enter pipes through cracks), treatment systems fail, or pathogen testing detects bacteria like E. coli or total coliform. Boiling water for 1 minute (3 minutes above 6,500 feet elevation) kills virtually all bacteria, viruses, and parasites. During a boil advisory, water should be boiled for drinking, cooking, ice making, brushing teeth, and washing produce. Bathing is generally safe during a boil advisory. Advisories are lifted after water testing confirms the water is safe. In 2023, approximately 3,000 boil water advisories were issued across the United States.
Related Terms
- Health-Based Violation — The most serious type of drinking water violation — indicating that water quality has exceeded a maximum contaminant level or failed to meet a treatment requirement that directly protects health.
- Chlorination — The most common method of disinfecting drinking water — adding chlorine or chloramine to kill bacteria, viruses, and parasites before water reaches your tap.
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About This Definition
This definition is part of the IsWaterSafe Drinking Water Safety Glossary — 22 terms explaining water contaminants, treatment methods, and safety standards. Written for homeowners, renters, journalists, and public health professionals.