Follow the new Check-Clean-Dry rules when you move between rivers and lakes.
The water we love
The invasive freshwater clam, found in the Waikato River in May 2023, can harm everything we love about the water. It can disrupt our recreation, clog water pipes, and threaten other freshwater species. The clam can only spread if humans move it between lakes and rivers with boats and gear.
How to Check-Clean-Dry
Check – for what is visible
Remove any visible matter, including any plant material, mud, or clams.
Drain all river or lake water.
Clean – for what is not visible
Washdown your watercraft, gear, vehicle, and trailer that has been in contact with river or lake water with tap water onto grass, beside the waterway or at home and not into a stormwater drain system.
For absorbent surfaces and materials (including wetsuits and carpet on trailers), use one of these treatments*:
Soak in hot tap water (55ºC) for at least 5 minutes.
Soak in diluted household bleach (10%, or 1 in 10 ratio) for an hour.
Freeze until solid (overnight).
(* Refer to the manufacturer's instructions if needed).
Dry – to be sure
Gear: Allow gear to dry to touch, inside and out, then leave it to dry for at least 48 hours (2 days) before using again.
Watercraft: Dry areas inside the watercraft where water has pooled, for example with an old towel, and then leave the craft to dry for at least 48 hours (2 days). The hull of a watercraft will dry when towed.
These new Check-Clean-Dry steps will also help stop the spread of other freshwater pest species.
Find out more
Comprehensive information, including biosecurity rules, what to do if you see clams, and the risk to New Zealand, is on our main response page.