How to: Clean & Filter your Tankwater, Post-Bushfire

Your tank water may also be contaminated if:

• the tank has been burnt by fire and/or the internal lining material is damaged
• the plumbing to or from the tank is damaged
• the water level has increased due to water bombing.

The presence of ash and debris in rainwater is unlikely to be a health risk, but could affect the appearance and taste. Fire retardants currently used in Australia are of low toxicity, but may also affect the appearance and taste of rainwater.

If you haven’t already done so:

1. Disconnect the down pipes and harvesting system from your rainwater tank. The first rainfall after the fire should be run to waste, if the roof has not been cleaned;
   
   
2. Clean your roof to remove ash and debris, if this can be done safely by a professional;
   
   
3. Check your roof and guttering for dead animals and remove if present;
   
   
4. Water testing is usually not necessary as contamination is obvious;
   
   
5. The contaminate water in the tank should be drained, and the tank cleaned and refilled from mains water if available. Working inside a tank can be very dangerous. If available, professional tank cleaners are available in most areas;
   
   
6. Filters and other water treatment equipment could also be affected by debris and grime. Hose off your pleated cartridges and replace your carbon cartridges. Refer to the manuals of your equipment or seek advice from the supplier on responses to problems; and
   
   
7. After drinking water has been captured or delivered, flush taps in the property to bring through the new clean water from the tank.

Disinfection and filtration of tank water:

To be 100% sure of your water supply we would recommend that the water in each case be tested by a certified laboratory before drinking, including testing for Arsenic and Chromium. 

Dural Irrigation in partnership with Puretec recommend a dual stage filtration system to remove sediment, odours and bacteria from your water supply creating safe drinking water. 

For sediment/ash removal, we suggest a 5 to 20 micron PL Series Pleated Sediment cartridge, and for smoke smell/taste we would recommend an activated CB Series Silver Impregnated Carbon cartridge.

In addition to filtration we recommend treating your tank water due to potentially increased bacteria in your supply.  Odour and discoloration are the main signs you my have bacteria or organic matter in your tank.  

Puretec TankSafe is a rain tank purifier that can kill up to 99.9% of all germs, bacteria and viruses in your rainwater.

We would also point out that filters may need to be changed more frequently, due to the higher than usual content of contaminants. 

Source reference

health.nsw.gov.au 

Puretec Group Australia