Stormwater Management
Stormwater is rainwater that flows directly across external surfaces into stormwater drains or directly into waterways. Stormwater should not contain pollutants originating from your business.
The stormwater from your business travels via the gutters and drains to local creeks or canals and eventually ends up in a river or the beach. If it is contaminated with pollutants such as litter, wastes, grease, oil or chemicals it can kill fish or other water life and seriously pollute the environment.
Allowing stormwater to become polluted is an offence which can result in an on-the-spot fine or prosecution.
Simple ideas to prevent stormwater pollution
- Keep the footpath, gutter and external areas near your business free from litter. Do not hose your outdoor surfaces into the gutter or drain.
- Provide containers for cigarette butts in areas frequented by smokers.
- Ensure that rainwater from roofs, yard areas, car parks etc. is directed to the stormwater system and not connected to the sewer, or reuse it in a rainwater tank.
- Check that any internal trade wastewater drains to the sewer not to the stormwater system. Any discharges to the sewer should be in accordance with the requirements of your local sewerage utility (Sydney Water, Hunter Water or your local council).
- Conduct all activities with the potential to pollute water within a roofed and bunded* area or indoors. Liquid waste and wastewater from these processes should be either:
- recycled on site
- treated and discharged to the sewer according to the requirements of the local sewerage utility (a trade waste permit must be obtained first) and/or
- collected in drums or tanks and removed by a licensed waste contractor for treatment and disposal at a licensed waste facility.
- Install bunds* across entrance and exit points of buildings and roofed areas to contain spills and washwater. Washwater must not enter the stormwater system but should be collected and either:
- discharged to the sewer in accordance with the requirements of the local sewerage authority or
- stored in drums or tanks and transported to a liquid recycling facility or
- collected and recycled or reused on site.
*Bunding
A bund is a simple and effective device to minimise the risk of liquid escaping to the environment. A bund generally consists of a low wall built to contain spills and leaks from fixed tanks and containers such as 200 litre (44 gallon) drums.
The construction of bunds should comply with Australian Standard AS 1940-2004: The Storage and Handling of Flammable and Combustible Liquids. If you are storing liquids that are classified under the NSW Dangerous Goods Act 1975, these liquids must be stored to comply with the requirements of the Act and, depending on quantity stored, may also require licensing from WorkCover.
The bund wall and floor area should be made of an impervious material such as
bricks or concrete and be large enough to hold the full contents of the largest container plus 10%.
Entrance bunds should be suitable for a forklift to drive over.
Containing spills
- Prevent any contaminants, spills or leaks from entering stormwater drains.
Make sure you have spill containment equipment such as absorbents, containment booms and brooms readily available. Put the equipment at a
designated spill station. A plan of the stormwater system should be displayed in a prominent position. - Install first-flush systems or stormwater cut-off valves (which remain closed unless it is raining) on the drainage system of any area where significant spills could occur.
- Install diversion drains or bunds (e.g. speed humps) to divert clean water away from relatively dirty areas to minimise the amount of potentially contaminated water requiring treatment.
- Store all drums and tanks within bunded areas.
- Store all waste skips and bins in a designated area provided with a roof and surrounded by a bund to prevent any leakage entering the stormwater system. Alternatively, establish a system whereby the lids are opened only when waste is being deposited and the skip's bottom and walls are permanently sealed so they do not leak.
Minor plant
- Provide roofs over and bunds around all minor plant located outside (e.g. compressors, generators, oil-water separators and trade waste treatment equipment.
- Direct air conditioner bleed-off water to the sewer in accordance with the local sewerage utility's requirements.
Plumbing
- The trade wastewater drains inside your premises should be connected to the sewer and not to the stormwater system.
- Check that cracked pipes or old plumbing connections are not transferring trade wastewater that you think is going to the sewer to the stormwater system. Ensure that any new plumbing connections to the sewer are in fact connected to the sewer and not to an underground stormwater pipe.
Further information
- DECC Environment Line, Tel: 131 555
- Your local council
Page last updated: 27 February 2011
