The Lake Illawarra Authority (LIA) is a statutory body representing the Crown.

Lake Illawarra is legally considered non-tidal due to the court case of The Attorney General v Swan 1921.

The NSW Registrar-General directs that the legal boundary between Lake Illawarra and privately owned land is defined as the original margin of the lake shown on the first survey.

The LIA has received advice from the Department of Lands that even after the entrance works were completed Lake Illawarra still remains legally non-tidal. This is because the opening has been achieved by artificial means.

Lengths of the side boundaries of lots (from the road reserve to the lake margin) shown on Deposited Plans of survey will not alter over time.

Any land on the lake side of the legal boundary of privately owned land, is public land vested in the LIA under the Lake Illawarra Authority Act 1987.

In June 2006 the LIA commissioned an independent survey to identify the legal boundary of the original margin of Lake Illawarra where private properties adjoin the Lake. This survey identified any structures that are located on LIA land.

Under the law (Lake Illawarra Authority Act 1987), structures such as jetties, boat ramps and slipways located on LIA land (eg; the original bed of Lake Illawarra) require a licence agreement. Similar laws cover these types of structures located on all waterways vested in the Crown throughout NSW.

A Licence Agreement gives the occupier of the licensed area the legal right to use the land for a jetty, boat ramp, slipway etc. A Licence Agreement is necessary to cover public liability issues.

Private property owners with attached structures located on land vested in the LIA have been offered a Licence Agreement. Many residents have already complied with this requirement.

Structures located on LIA land that are not authorised under the Lake Illawarra Authority Act 1987 and are not covered by a Licence Agreement will be required to be removed.

An application for owners consent should be submitted to the LIA before any construction work on structures such as boat ramps, jetties or slipways is undertaken on land vested in the LIA.