Precautions for water header tanks during a Boil Water Alert

This advice is to be followed for water header tanks when your water supplier has issued a boil water alert. When a boil water alert is lifted, building owners/managers should take a number of precautions before allowing water from building storage header tanks to be consumed.

If the storage header tank hasn't been cleaned in the previous 12 months

The tank should be cleaned and disinfected in accordance with Australian Standard 3500 TITLE: National Plumbing and Drainage Code

If the tank has been cleaned in the previous 12 months​

The tank should drained and refilled before the water is declared safe for drinking.

Flushing internal plumbing

Flushing of internal plumbing within centres can be achieved with three simple steps:

1. Identify options for collection and reuse of flushed water, e.g. plant watering.
2. Identify the taps or bubblers furthest from the water meter. Open the taps to allow water from the main to flush the building’s pipes. Let the taps run for at least 2 minutes. Flushing for a longer period of time (up to 5 minutes) or selecting outlets at a number of locations may be required in buildings with larger water distribution systems in order to draw fresh water from the incoming water supply. Flushing times should be set to draw water from the tank through to the outlet being flushed.
3. Flush each drinking water outlet for about 10 seconds to remove water that has been sitting in the taps and bubbler valves.

Precautions during a boil water alert

• Schools and child care centres
• Topping up swimming pools and spas
• Commercial establishments serving food or drink to the public