Point and nonpoint sources of water pollution

Pollutants enter the water environment from two main types of sources.

Point sources

A point source is a single, identifiable source of pollution (Wikipedia), such as a pipe or a drain. Industrial wastes are commonly discharged to rivers and the sea in this way. High risk point source waste discharges are regulated by EPA through the works approval and licensing system, and associated compliance and enforcement activities.

EPA’s regulation of point source waste discharges has been important in improving the quality of Victoria’s water environment over the past 40 years. No longer do we have raw sewage and abattoir waste continually flowing in our rivers as per the 1970s. While focus and effort is still needed to maintain and improve these further, some of the major threats to the health of Victoria’s water quality are now from nonpoint sources.

Nonpoint sources

Non-point sources of pollution are often termed ‘diffuse’ pollution and refer to those inputs and impacts which occur over a wide area and are not easily attributed to a single source. They are often associated with particular land uses, as opposed to individual point source discharges.

Urban land use

In our urban areas rainfall run-off as stormwater is one of the major nonpoint sources of pollution impacting the water quality of our waterways and bays. Stormwater from street surfaces is often contaminated with car oil, dust and the faeces of animals and soil and sediment run-off from construction sites, and in industrial areas often contains more toxicants and chemicals.

In some outer-urban and urban fringe areas, a reticulated sewerage system is not available so sewage is discharged to onsite wastewater systems and septic tanks. Seepage and surface run-off of septic tank effluents may also be forms of non-point source pollution of streams in these areas.

Agricultural land use

In farming areas non-point sources of pollution include pesticides, fertilisers, animal manure and soil washed into streams in rainfall run-off. Where stock are given access to stream banks they may foul the water and accelerate erosion.

Forestry land use

Forestry operations may contribute to non-point source pollution of streams by increasing soil erosion and sediment run-off.

Non-point source pollution is often more difficult to control than point source pollution. In urban areas the provision of reticulated sewerage systems and adequate street cleaning are important measures, while in farming and forestry areas, soil conservation practices and the controlled application of pesticides and fertilisers are necessary if pollution of waterways is to be avoided.

While EPA does not directly licence or approve many of these non-point source activities through regulation, we often work with other partners from government, industry and community across different aspects of our operating model to help tackle these issues.

Page last updated on 27 Jul 2012