The catchment area supports a wide variety of land use including:

• urban and industrial development
• sand extraction
• infrastructure
• tourism and recreation
• natural and modified open space
• commonwealth military reserve
• water harvesting for domestic and industrial use
• agriculture: horticulture (market gardens) and animal husbandry

The Sydney Metropolitan catchment supports the most populated city (Sydney) in Australia. Urban development is the predominant land use. Urban land use includes commercial centres, residential and industrial areas and urban infrastructure. Increased pressure for density housing within the region affects not only the CBD but the suburbs with natural values and high cultural heritage values and other areas of recent development activity.

The region supports significant industrial development, major petroleum and chemical plants. It also supports important extractive industries, the Kurnell Peninsula is a major supplier of fine sands to Sydney's construction industry and supplies almost half of Sydney's current construction industry demand.  These sand mining activities have a finite life and alternate sand sources are under investigation.

The area supports major infrastructure assets including Sydney's international and domestic shipping facilities as well as airports and motorways.  Sydney has the second largest container port in Australia.  Sydney's ports are a major infrastructure asset for NSW and are a significant part of the State's economy.  They handle nearly one third of Australia's total containerised trade.  Sydney Airport is one of Australia's most important transport facilities and in 2004 received nearly half of Australia's international visitors and approximately one third of its domestic visitors.

Tourism is a major industry and the catchment provides a diverse range of recreational and tourism facilities. Sydney Harbour is Australia's number one tourism asset.

Approximately 37% of the SMCMA's area is composed of native vegetation and of this approximately 42% is in conservation reserves. The Holsworthy Military Reserve is the Australian Army's principal military establishment in metropolitan Sydney. It is situated on a deeply dissected part of the Woronora Plateau and covers an area of 19,000 ha to the south of Sydney.  The vast majority of the military reserve is natural bushland, although there are some built areas in the north of the site.

There are two Sydney Catchment Authority (SCA) water storage facilities located in the Georges River catchment:  Prospect Reservoir and Woronora Dam.  The catchments for both facilities are closed to the general public and also have relatively undisturbed native bushland. Botany Sands Aquifer bore water supplies are used for industrial purposes such as cooling and manufacture of paper and chemical products.  The water is also used for irrigation of parks and gardens, golf links and bowling greens.  Natural groundwater discharge from the sand bed aquifer supports important dependent ecosystems such as the Botany Wetlands.

Traditional agricultural activities are limited to the urban rural fringe areas in the western and south west of the catchment. Culturally significant market gardening still operates within the built up areas around Botany Bay and supplies much of Sydney's fresh vegetables, flowers, and fruit.