Know and follow the 'Check Clean Dry' rules
We all have a role in protecting New Zealand's lakes, rivers and wetlands. Some regions have legal requirements called Controlled Area Notices to help prevent the spread of invasive freshwater weeds and pests. On this page is information about the Controlled Area Notices in place.
Whether you live in these regions or are visiting their waterways, it’s important to know and follow the rules in place. By doing your part, you can help stop the spread and protect our precious freshwater environments.
Under the Biosecurity Act 1993, it is illegal to knowingly spread freshwater pests such as didymo or freshwater clams. Following 'Check Clean Dry' and any requirements under Controlled Area Notices helps protect New Zealand's waterways from invasive freshwater pests.
Waikato River – Whakamaru Dam to Port Waikato
If you have used a ballasted boat in the controlled section of the Waikato River, you must not use it in any other freshwater or brackish waterway, including parts of the Waikato River outside the controlled area.
For other recreational river users, if your craft or gear has been in the controlled stretch area, you must 'Check Clean Dry' before using it in another waterway. This includes fishing gear and other equipment used to gather kai, as well as water skis, wakeboards and inflatable pool toys.
Waikato River Controlled Area Notice [PDF, 348 KB]
Te Arawa Lakes – Bay of Plenty
If your boat has been used in any part of the Waikato River within the past 30 days, you must have it cleaned at a designated wash station before entering any of the 14 Te Arawa Lakes. While at the wash station, boaties must scan the QR code to confirm that the boat has been washed.
If fishing gear or other equipment used to gather kai has been used in any part of the Waikato River within the past 30 days, you must Check Clean Dry before using it in the Te Arawa Lakes.
There are additional requirements for Lake Ōkataina. All recreational water users must clean their boat or craft at the designated wash station before entering the lake. Once the wash has been completed, scan the QR code at the wash station to receive a PIN to access the lake gate.
Te Arawa lakes and Lake Ōkataina Controlled Area Notice [PDF, 499 KB]
Notice of amendments to Corbicula fluminea Controlled Area Notice (December 2025) [PDF, 412 KB]
South Island
The entire South Island is covered by a Controlled Area Notice for the invasive freshwater algae didymo, also known as rock snot. Didymo was first detected in the South Island in 2004.
Under the Controlled Area Notice, it is a legal requirement to 'Check Clean Dry' all gear used in the water before moving from one South Island waterway to another. This helps prevent didymo from spreading to new waterways.
So far, didymo has not been found in the North Island.