Only clean, uncontaminated rainwater should enter a stormwater drain. Water that looks clear is not necessarily safe because it may still contain dissolved chemicals, detergent or other pollutants.
What counts as clean rainwater?
Clean rainwater is rainfall runoff that has not collected waste, chemicals or harmful residues. Runoff from a roof, driveway or paved area may enter the stormwater system designed for it, provided the water has not been contaminated.
Once water has been used to wash a vehicle, floor, bin, tool, pet or equipment, it is wastewater, not clean rainwater. Products labelled biodegradable or non-toxic should not be put into stormwater unless the relevant authority specifically permits it.
What must be kept out?
Keep all wastewater and contaminated runoff out of stormwater drains. Check what should never be poured down a drain before disposing of an unfamiliar liquid.
- soapy water and cleaning water
- paint wash-water, plaster slurry and concrete washout
- cooking oil, engine oil, fuel and coolant
- solvents, degreasers and disinfectants
- pesticides, herbicides and fertilisers
- pool or spa water unless the relevant authority expressly permits discharge and its conditions are met
- water containing soil, sediment, sewage, food or animal waste.
Stormwater carries rainfall runoff, while toilets, sinks, showers and laundries discharge through an authorised wastewater system. Check where household sewer and stormwater drains lead, and do not assume every unwanted liquid can go into the sewer. Disposal requirements depend on the substance.
Across Sydney, much of the stormwater network discharges to creeks, rivers, harbour waters or the ocean without sewage treatment. Wastewater can therefore carry sediment, microbes, nutrients and toxic substances directly into local waterways.
If you are unsure how to dispose of a liquid, contain it safely and check its label and current NSW EPA, local council or Sydney Water guidance. Do not mix substances or hose spills into a gutter. Avoid contact with unknown or hazardous chemicals, and call 000 if a spill poses an immediate danger to people, property or the environment.
If an outside drain is blocked or its connection is unclear, do not test it with wastewater. Contact our licensed Sydney stormwater plumbers to identify the system and advise on the next step.