Lesson · Biological & Public Health Hazard Literacy

Safe Water and Sanitation After a Disaster

Why waterborne disease causes more post-disaster illness than the event itself, how to make water safe with what is available, and how sanitation siting protects a whole shelter.

  • General Public
  • Teacher
  • Student
  • Institution
  • Responder

Learning objectives

  • Explain why water sources become contaminated after flooding and structural damage.
  • Describe boiling, chlorination, and filtration, and state the limits of each.
  • Site a latrine relative to a water source so that contamination is prevented.
  • Recognize the early signs of waterborne illness and know when to escalate.

In the field

Ordered, and meant to be workable under pressure. Numbered because the sequence matters.

  1. Treat all flood-contacted water as unsafe until it has been boiled or properly chlorinated.
  2. Bring water to a rolling boil, or chlorinate at the dose the health authority specifies.
  3. Site latrines downhill and well away from any well or water point, never upstream of one.
  4. Set up a handwashing point with soap at the latrine and at the eating area.
  5. Escalate any cluster of diarrhoeal illness to the local health unit the same day.

Sources · 3

The tag under each source states what was actually checked. “Authority named · URL not re-resolved” means the issuing body and document are named, but the link was not re-resolved for this lesson. It is not a claim of verification, and the authority’s own current bulletin always supersedes anything here.