Stormwater Management

By practicing good manufacturing practices with your water systems, your business will assist with preventing rubbish, grease and other waste from entering the stormwater drainage system.  This information has been collated by Metropolitan Waste and Resource Recovery Group.


Please also check further information from Sustainability Matters.


What is stormwater?

When it rains, water runs off your roof, down into pipes or directly off the ground and into the nearest drain.  Stormwater is the water that runs off after the rain.


After flowing into the gutters this stormwater runs through the drains that lead to the nearest creek, river, lake or ocean.  Stormwater is discharged from drains into the natural waterways without any treatment to remove the pollution.


What is stormwater pollution?

Stormwater pollution includes waste products from food businesses such as litter, grease, oil and detergents.  Natural waste such as grass, plant clippings, soil or other organic matter may also cause serious issues with in the creek, river, lake or ocean.  Such waste items are unsightly, block drains, can cause flooding, and use up the oxygen in the water as they decompose.


Each time it rains, water flows over outdoor surfaces and washes these waste items from roads, footpaths, and yards into stormwater drains and waterways.  These pollutants damage the waterways and harm plants, animals, and human health when people swim, boat or fish in these affected wasters


There are more than 100,000 drain outlets in Melbourne alone that discharge stormwater into the waterways.  Most stormwater pollution is derived from everyday household and small business activities.  It is these small, everyday activities that accumulate and cause more stormwater pollution than major spills or industrial accidents.


Commercial businesses have the potential to pollute stormwater through activities such as sweeping litter into gutters, hosing spills into gutters or drains, or tipping soapy water into gutters or drains.


Know your drains

There are two types of drainage systems: stormwater drains and a sewer system to collect and properly treat waste water.


Stormwater drain: The stormwater drain systems consists of gutters, street drains, and underground pipes that collect rain and carries it to the nearest creek, river, lake or ocean.  This water is not treated.  Examples:

Drain Stormwater 3

Drain Stormwater 1 Drain Stormwater 2


Sewer system drain: Wastewater is used or contaminated water resulting from human operations.  Wastewater includes all dirty water from cleaning, mopping, etc.  The sewerage system collects this wastewater from toilets, kitchens, bathrooms, and laundry fixtures and carries it to the sewerage treatment plant.  Examples:

Drain Sewer 1

Drain Sewer 2 Drain Sewer 3

The sewerage system is managed by the local water authority (example: Yarra Valley Water, City West Water, etc).


Oil and grease

Why it’s bad:

  • Oil solidifies in drains and may cause blockages
  • Oil contaminates water in rivers and harms plants and animals
  • A little bit of oil can cause a lot of damage: for example, one litre of oil can contaminate one million litres of water



  • Ensure oil is not kept anywhere where it can spill into drains
  • Never hose oily water or waste into gutters or stormwater drains
  • Cooking oil should be stored in a secure area that does not drain into stormwater
  • Materials to soak up oil or grease spills should be kept nearby to assist with clean-up in case of spillages
  • Ensure exhaust canopies are cleaned regularly (minimum every six months) by a licensed contractor – dirty canopies can leak grease onto your roof and into stormwater drains and may cause a fire risk
  • Used cooking oil must be collected by a licenced waste collector



Why it’s bad:

  • It is unsightly and can enter stormwater drains
  • Litter contaminates water in rivers and harms plants and animals



  • All litter outside of businesses should be swept up and placed into rubbish bins
  • Ensure waste is not able to be blown or washed away into gutters and drains
  • Ensure your gutters and drains are litter-free
  • Consider broken glass fragments that could wash away into drains and harm animals


Outdoor café suggestions:

  • Provide secure, windproof litter bins that are used by both staff and customers
  • Reduce litter from street tables by removing individual potion controlled items such as sugar sachets
  • Provide tap water rather than bottled water
  • When offering drinks from a bottle, remove the lid within the café
  • Provide lidded ashtrays. Alternatively, ensure you comply with the Tobacco Act and Litter Laws by advising staff and customers where a butt bin is located to properly dispose of their cigarette butts
  • Encourage correct behaviour from both staff and customers by displaying signage and providing appropriate bins


Liquid waste

Why it’s bad:

  • Liquid waste contaminates water in rivers and harms plants and animals



  • Never tip oil, chemicals, detergents or water containing these items into stormwater drains
  • Never hose down floors, driveways, yards, or bin storage areas that drain into stormwater
  • Store liquid waste securely and have it collected by a licensed waste collector
  • Liquid waste must be stored in an area where any spills can be contained so it is easy to clean them up
  • Liquid spills should be soaked up with an absorbent material and discarded in bins
  • Use materials from a spill kit to absorb the spilt liquid, such as sawdust or unused kitty litter
  • Ensure containers storing liquid waste have secured, fitted lids
  • Consider a drip tray to capture any possible spillages
  • Always tip dirty mop water down the cleaners sink
  • Where possible, use environmentally friendly cleaning products instead of harsh chemicals that produce poisonous fumes and pollute water
  • For bin washing, ensure the drains are connected to the sewage drains system, not the stormwater drain system


Grease traps

Waste water from all kitchen fixtures, including hand wash basins travel through the grease trap unit and then into the sewer system.  A grease trap is designed to:

  • Trap food particles, which settle in the bottom of the pit
  • Trap grease, oil and fats, which float to the top of the pit and eventually harden and solidify
  • Allow the wastewater that is in between the floating layer of fats and grease and the food particles at the bottom to pass through into the sewer

Grease traps must be properly installed and maintained, including regular cleaning and emptying by a licensed contractor (minimum every three months).


How to prevent waste entering the stormwater drainage system

[1] Check your drains

  • Check which drains on your premises are connected to sewer and the food and oil interceptor (otherwise known as “grease traps”)
  • Label the storm water drains on or near your premises and inform your staff. For example: “Stormwater Drain Just for Rain”
  • Keep all drains clear and clean of litter
  • Sweep paved areas clear of rubbish
  • Ensure food waste, detergents and oil cannot spill from the grease trap, rubbish bin or yard into the stormwater drains


[2] Wash equipment and floors responsibly

  • Ensure staff have easy access to an appropriate Cleaners Sink or drain
  • Ensure the cleaners sink or drain is connected to the grease trap for disposing of all washes and waste water
  • Ensure staff are aware which sink is the cleaners sink – suggest it is clearly labelled. For example: “Cleaners Sink”
  • Ensure dirty, soapy, or oily water from floor mopping, high pressure cleaning, exhaust filter cleaning, floor mat cleaning, or any liquid containing flaking or left over residual paint or other chemicals are tipped into the cleaners sink or drains connected to the grease trap
  • For bin or exhaust fan washing, ensure dirty water is poured down the cleaners sink or drain. Alternatively, take the bins or exhaust fan equipment needing a wash to a suitable wash provider or hire a wash / exchange service
  • Use biodegradable cleaning chemicals where possible


[3] Secure your bins and outside items

  • Ensure bins are not overflowing and have secured lids to ensure litter does not blow away
  • Ensure there are no cracks or leaks in the bins allowing waste to escape
  • Avoid positioning bins on or near stormwater drains


[4] Store and manage build liquid appropriately

  • Ensure stored chemicals, detergents, and oils do not leak and are stored away from storm water drains
  • For items that may be able to wash off site, ensure these are stored elevated from flooring or over a drip tray/collection tray to prevent the getting to the stormwater drains


[5] Responding to issues

  • In the event of contamination, contain or collect or redirect the flow as quickly as possible away from the stormwater drain and secure the area
  • Contact your local council to obtain the appropriate advice for the clean-up action required


Trade Waste Agreement

All commercial businesses that prepare food must be registered with the local water local water authority (example: Yarra Valley Water, City West Water, etc).  A Trade Waste Agreement is a licence to discharge wastewater into the sewer.  Wastewater includes dirty water generated from cleaning, washing, or rinsing processes that may contain chemicals, fats or detergents.


While wastewater is treated, the correct usage of the sewer system is important to ensure that the system is not overloaded.  An overload of the sewer system results in a spill into the stormwater system.  In order to properly manage and treat wastewater, water authorities must understand the volume and composition of wastewater being disposed of.



  • Trade Waste Agreement: Contact your local water supplier to discuss waste water management. Obtain a site map of your premises that will identify which drains are stormwater and which lead to the wastewater drainage system.
  • Which drain is which? Contact a plumber to assist you
  • Council Transfer Station: Check with your local council if there is a Transfer Station – you may be able to drop off small quantities of used cooking oil for free
  • Licensed waste collector: Google to find a licensed waste collector for “cooking oil collection”
  • Grease trap collector: Google to find a licensed waste collector for “grease traps”
  • Licensed canopy cleaner: Google to find a licensed canopy cleaner
  • Spill kits: Google “spill kits” to find suppliers of spill kits
  • Bin washing: Google “mobile bin washing” to find a contractor of bin washing


Further information

  • Your local council
  • Your local water authority
  • EPA | Environment Protection Authority


Environment Protection Act 1970

Businesses have a responsibility to prevent the discharge of waste water from their property.  This is enforced through the Environment Protection Act 1970 and through council local laws.  These laws exist to protect the natural environment.


Fines apply should a business cause stormwater pollution.  These fines may be issued through the EPA or local council.  On the spot fines may range between $300 to $600.  In serious cases, a person may be charged and prosecuted through the court system and fined to up to $7,000.


Download this article: Stormwater Management


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