Rainwater & Avian Influenza (H5N1) - Frequently Asked Questions

Has bird flu (H5N1) been found in New Zealand?

Yes, in July this year recent detections of H5N1 in New Zealand have been found. Understandably raising questions about the safety of roof-collected rainwater, particularly where birds regularly visit rooves and gutters.

Can bird droppings contaminate roof water?

Yes. Any bird droppings on a roof can introduce microorganisms into rainwater as it washes into storage tanks. This is why good rainwater management and effective water treatment are important, regardless of whether avian influenza is present.

Is Chlorine Ddioxide effective against avian influenza viruses?

Yes. Overseas scientific research has shown that chlorine dioxide can inactivate avian influenza viruses, including H5 strains, under controlled laboratory conditions. Chlorine dioxide has also been widely used around the world as a broad-spectrum disinfectant for drinking water and is effective against many bacteria, viruses, and other microorganisms.

Does this mean DX50 is proven to eliminate H5N1 in roof water?

There are currently no published studies that specifically evaluate DX50 treating roof-collected rainwater contaminated with H5N1 from bird droppings.

However, because DX50 uses chlorine dioxide as its active disinfectant, the available scientific evidence supports its role as an effective water disinfectant when used at the correct dose and with adequate contact time.

Is my current DX50 Chlorine Dioxide dosing still appropriate?

For most customers, yes. If your DX50 system is correctly installed, properly maintained, and dosed according to our recommendations, it should continue to provide effective disinfection of your stored rainwater.

If you're unsure about your dosing rate or would like us to review your system, we're happy to help.

What else can I do to protect my water supply as a multi barrier approach?

Good rainwater management is just as important as water treatment.

We recommend:

* Keeping roofs and gutters as clean as practical.

* Removing accumulations of bird droppings where it is safe to do so.

* Maintaining first-flush devices, where fitted.

* Keeping water storage tanks well sealed to prevent animals and debris entering.

* Ensuring your DX50 Chlorine Dioxide dosing system is operating correctly and maintained regularly.

Why is Chlorine Dioxide used for drinking water?

Chlorine dioxide is recognised internationally as an effective drinking water disinfectant. It provides broad-spectrum control of microorganisms, performs well over a wide pH range, and can penetrate biofilms more effectively than many traditional chlorine treatments. These characteristics make it well suited to treating stored rainwater where water quality can vary.

While no water treatment system can completely eliminate every possible risk under every circumstance, maintaining your DX50 Chlorine Dioxide System at the correct dosage provides a high level of protection against a broad range of waterborne microorganisms.

Where can I get more information?

If you have any questions about your DX50 system, your dosing rate, or your rainwater supply, please contact us.