Safe water in Bangladesh: arsenic, floods and what to store

Short answer. In Bangladesh the main drinking-water risk is arsenic in tube-well water: the national standard is 0.05 mg/L, five times the WHO guideline of 0.01 mg/L ¹. After floods, the Department of Public Health Engineering (DPHE) says to boil water for at least 5 minutes after it bubbles, or to add one 25 mg Halotab tablet to 5 litres and wait 30 minutes ².

Is my tube-well water safe?

Not necessarily. The National Policy for Arsenic Mitigation (2004) says 97% of the population relies on groundwater for drinking, and that in many areas it contains arsenic above the Bangladesh standard of 50 parts per billion (0.05 mg/L) ³¹. The share of contaminated tube wells varies from more than 90% to less than 5% between villages ³. The policy provides for the screening and regular monitoring of all tube wells, and for testing every new water source before use ³. DPHE publishes the Bangladesh standard and the laboratory method for arsenic and the other drinking-water parameters ¹. See Private well emergencies and Tap water quality reports.

How do I make water safe after a flood?

DPHE's guide for floods and disasters ²:

• Tube well: use it if the well and its source were not under flood water; otherwise boil or disinfect the water before drinking.
• Rain water: safe if collected in clean containers or from a clean roof; when collecting from a tin roof, let the first 10 minutes of rain run off.
• River or pond water: only if no safe tube-well water is available; strain it through cloth, then boil it or use purification tablets or powder.
• Boiling: keep it boiling for at least 5 minutes after it starts to bubble.
• Tablets: follow the brand's instructions; for example, one 25 mg Halotab in 5 litres of clean water, then wait 30 minutes before drinking. Keep tablets dry and out of children's reach.
• Alum: stir half a teaspoon into a 20-litre bucket, wait 1 hour, pour off the clear top water and disinfect it with tablets or powder before drinking.

DPHE also explains how to disinfect a tube well with chlorinated bleaching powder after repair or raising ². See Water safety after a flood and How to purify water.

How much water should I store?

Bangladesh publishes no figure in litres per person. The Department of Disaster Management asks households to store safe drinking water with dry food once a cyclone signal is issued ⁴. The arsenic policy sets 8 litres per person per day as the minimum for rural piped supply for drinking and cooking ³; that is a service level, not a storage target. See How much water to store per person and the Bangladesh kit page.

Is Bangladesh short of water?

In its largest cities, yes. In WRI's Aqueduct 4.0 model, the population-weighted median of Bangladeshi cities is "extremely high" for current water stress and stays "extremely high" in the 2050 business-as-usual projection; drought risk is "high" ⁵. These are city medians dominated by the Dhaka area: Khulna and Rajshahi, for example, sit in lower stress categories ⁵. The Bangladesh Meteorological Department publishes Standardized Precipitation Index drought maps, last posted in 2019 ⁶. See Drought preparedness.

Frequently asked questions

What is the arsenic limit for drinking water in Bangladesh?

0.05 mg/L (50 parts per billion), against 0.01 mg/L in the WHO guideline ¹³.

How long should I boil water in Bangladesh?

At least 5 minutes after it starts to bubble, says DPHE ².

Is rain water safe to drink?

DPHE says rain water collected properly in clean containers is safe; let the first 10 minutes from a tin roof run off ².

Preparedness index: Bangladesh ranks 54th of 67, 44.5/100 · full ranking