Water quality information and resources for water users

Water quality

Good quality water is essential for public health, economic production and healthy river ecosystems.

Poor water quality can:

  • put stress on a range of aquatic plants and animals
  • affect Aboriginal cultural and spiritual uses of water
  • increase the cost of drinking water treatment
  • contribute to public health risks
  • decrease the suitability of water for irrigation and agriculture.

Land use, geology, climate, riparian vegetation and stream flow influence water quality. Natural processes and man-made practices also impact water quality.

Features of water quality include:

  • physical features (temperature, salinity, turbidity)
  • chemistry (pH, dissolved oxygen, nutrients, toxicants)
  • biological content (bacteria, algae)
  • the water’s purpose
  • the water’s use.

Water quality is dynamic and varies with time and location. Water may be fit for one purpose, but not another. For example, water may be of good quality to irrigate crops, but may not support a healthy population of fish. Water quality can degrade during droughts and floods.

Human drinking water

During drought, the pressure to balance drinking water supply with demand increases. It is important in drought that systems to protect community health are not relaxed. Untreated water from dams, rivers and groundwater is not safe for human consumption.

Further information:

Household water supply

Information on managing household water supply during drought is available on DPI’s Drought Hub’s frequently asked questions.

Farm water

DPI has prepared some ‘Primefacts’ on water quality issues related to farm water use. Links to these Primefacts are below. They cover water quality issues relating to domestic, livestock and irrigation water use.

Farm water quality and treatment

Farm water comes from a variety of sources so its quality varies. It is important to identify farm water quality problems and know how to treat them. DPI’s Primefact on farm water quality and treatment describes water quality issues and how to manage them.

Treatment advice can be sought from farm water supply businesses.

Landholders may also choose to buy the NSW DPI’s practical handbook on farm water. The handbook outlines the technical problems involved in domestic and livestock water supplies.

Farm water quality – testing and treating for stock and domestic use

Information on where you can get water quality testing done is on the DPI’s website. There is also information on what tests you can do to assess if water is suitable for domestic or livestock use.

Water testing is available through the Wollongbar Primary Industries Laboratories for a fee. Staff can help answer your questions about the tests and interpret the results. Call 02 6626 1103 or email wollongbar.csu@dpi.nsw.gov.au.

Interpreting water quality test results

DPI’s Primefact on interpreting water quality test results helps to explain results.

Farm water quality and Treatment: Algae

DPI’s Primefact on farm water quality and treatment outlines the management of algae.

Desalination of bore water

Desalination of bore water may be a practical option for some landholders. It converts water high in salts to water suitable for domestic or livestock use. DPI’s Primefact on desalination of bore water discusses treatment options.

Stock water

When the quality of the water is poor, livestock may drink less than their daily requirements or stop drinking altogether. This causes loss of condition and productivity, and impacts animal welfare. The most common issues affecting livestock water quality are salinity and blue-green algae.

Water requirements for sheep and cattle

There are specific water requirements for cattle and sheep. DPI’s Primefact on water requirements for sheep and cattle outlines water essentials.

Stocktaking water supply for livestock

DPI’s Primefact on stocktaking water supply for livestock provides tips for understanding if water is fit for purpose.

Water for livestock: interpreting water quality results

To determine if water is suitable for livestock - test pH, salinity and chloride levels. DPI’s Primefact on water for livestock: interpreting water quality tests helps landholders understand water quality results.

Desalination of bore water

Desalination of bore water to make it suitable for livestock drinking water, is an option for some landholders. DPI’s Primefact on desalination of bore water explains this process.

Blue-green algae poisoning of livestock

Blue-green algae, also known as cyanobacteria, is potentially toxic. Blue-green algae can form dense blooms in freshwater bodies. Symptoms, diagnosis and tests are on DPI’s blue-green algal poisoning webpage.

Irrigation water

Provided landholders use best management practices and ecologically sustainable development principles, the quality of water used for irrigation should not impact crop yield or degrade soil or produce. Issues such as salinity, sodicity, pH and blue-green algae may impact the quality of irrigation water.

Salinity tolerance in irrigated crops

DPI’s Primefact on salinity tolerance in irrigated crops explains how different crops tolerate salinity in irrigation water. Salinity in irrigation water is measured by electrical conductivity (EC). Real-time water data by WaterNSW includes EC values for some river gauges in NSW.

Irrigating with blue-green algae affected water

Water from rivers or farm dams used to irrigate crops could become contaminated from a blue-green algal bloom. DPI’s Primefact on irrigating with blue-green algae affected water provides advice on this issue.

Hypoxic blackwater

Hypoxic (low oxygen) blackwater is a natural feature of lowland river systems. Blackwater occurs when organic material (sticks, leaves, bark and grass) breaks down in flood water. Bacteria break down this material. This can lead to a sudden decrease in the oxygen available to fish and other aquatic organisms. The black colour occurs as the organic matter decays.

The Department of Environment and Energy has information on hypoxic blackwater events and water quality.

The Murray–Darling Basin Authority has prepared a water management 101 factsheet on blackwater.

Real-time water data by WaterNSW includes DO values for some river gauges in NSW.

Blue-green algae

Most algae are safe and are a natural part of aquatic ecosystems. But some types of blue-green algae (cyanobacteria) can produce toxins and contact irritants. If they occur in bloom proportions, they pose a serious risk to human, animal and ecosystem health.

Warm, still, clear and nutrient rich water can encourage the growth of algae.

The WaterNSW web page on algae provides up to date information on algal blooms in NSW, including an algal alerts map. It also explains what causes algal blooms and how to identify them.

Reporting water quality incidents

The NSW EPA works with all stakeholders to improve water quality in NSW. Report water pollution incidents to the NSW EPA 24 hour pollution hotline - 131 555.

Report suspected algal blooms during business hours to WaterNSW - Regional Algal Coordinator in your area of NSW. At all other times, email RACC@waternsw.com.au with details of the suspected bloom.

Report fish kills to DPI Fisheries Fishers Watch Phone line on 1800 043 536.

More information

We have prepared Water Quality Management Plans for each Water Resource Plan Area in NSW. They are schedules in the water resource plans.

Water Quality Australia has a wealth of information about water quality. The current guidelines for water quality management and other resources may be useful.