Drinking water suppliers who were operating immediately before 15 November 2021 but who were not registered with the MoH do not need to register yet. Unregistered suppliers (except water carriers) will need to register by November 2025 and fully comply with the requirements of the Water Services Act by November 2028.
https://www.taumataarowai.govt.nz/for-water-suppliers/register-your-supply/
If you transport drinking water please see the link below for information on how and when you need to register.
https://www.taumataarowai.govt.nz/for-water-suppliers/for-water-carriers/