Is my tap water safe after a flood or storm?

When water turns unsafe

After heavy rain, floods, or a burst water main, two risks come up:

• Contamination. Bacteria like E. coli or giardia, sewage backflow, agricultural runoff.
• Sediment and metals. Pipe disturbance loosens rust, sediment, and occasionally lead from old service lines.

The official boil notice

Your local water authority posts boil-water advisories within hours of any contamination event. Check their website or social media. If a notice is in effect:

• Boil tap water for one full minute at a rolling boil before drinking.
• Use boiled or bottled water for brushing teeth, washing produce, and ice.
• Showering is usually fine for adults. Keep eyes and mouth closed.
• Pets need boiled water too.

Brown water

Discoloured water is usually iron, manganese, or sediment, not always dangerous but unpleasant. Run the cold tap for five minutes. If it doesn't clear, ring the water authority. Don't use the hot tap (it draws from the heater tank where sediment settles).

Filters and their limits

Pitcher filters (Brita and similar): Reduce chlorine, taste, some heavy metals. Don't reliably kill bacteria. Useless during a boil notice.

Reverse osmosis: Removes nearly everything, including dissolved metals. Wastes some water in the process. Worth it if you have ongoing concerns or genuinely hard water.

Carbon block filters (NSF 53 certified): Remove lead, chlorine, many VOCs. Good middle ground.

Test if you're unsure

A home water test kit costs $20 to $80 and checks lead, bacteria, hardness, nitrates, and more in 10 minutes. Cheap insurance after a major plumbing event in your area.

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