The LERNZdb Freshwater Database is a repository for freshwater quality data and biodiversity measurement data for lakes, rivers and wetlands in New Zealand. It was developed as part of the Lake Ecosystem Restoration New Zealand (LERNZ: LERNZ.co.nz) programme in co-operation between the Information & Technology Services Division (ITS) and LERNZ researchers at the University of Waikato. LERNZdb has the ability to store a wide variety of freshwater data in a consistent format, it also scores the quality of the data based on the provided quality controlled information. This allows the user to filter data based on the standard of data collection and encourages the provision of high quality data for use in modelling applications.