Stormwater Management
Why is stormwater management important?
The stormwater from your factory travels via the gutters and drains to local creeks or canals and eventually ends up in a river, a harbour or on a beach. If it is contaminated with pollutants such as litter, wastes, grease, oil or other chemicals it can kill fish and other water life, and seriously pollute the environment where people swim, fish and play. Keeping stormwater clean is important.
Some of the activities carried out in small factories have the potential to pollute stormwater and therefore have an impact on the water quality in our local waterways. Allowing stormwater to become polluted is an offence that can result in an on-the-spot fine or prosecution.
What's the difference between stormwater and wastewater or sewage?
Stormwater is rainwater that flows across outside surfaces into the stormwater system. The stormwater system includes street gutters, drains, underground pipes and channels that transport rainwater to waterways. Stormwater is generally not treated to remove pollutants. It is therefore important to keep all pollution out of the stormwater system.
The sewerage system is separate from and different to the stormwater system. It includes underground pipes and main trunk lines which transport sewage from homes, and wastewater (liquid wastes) from businesses, to sewage treatment plants. After the sewage is treated and the solids are removed, the liquid or effluent is discharged to rivers or the ocean.
Wastewater (sometimes called trade wastewater) is any water used or contaminated in conducting your business processes and activities. Wastewater from businesses may contain pollutants such as sediment and chemicals. Businesses must have a permit from the local sewerage utility before discharging wastewater to the sewer. Refer to Trade Wastewater for advice on wastewater disposal.
What do you need to know about stormwater pollution and your business?
You should know that it is against the law to pollute water or place pollution in a position where it could be blown or fall into a drain, gutter or local waterway. Pollutants include any dirt, wastes, litter, oil, grease, metals, paints, detergents, acids, alkalis, plastics, papers, etc.
Simple things you can do to prevent stormwater pollution from your business
- Keep the footpath, gutter and external areas near your business free of litter. Take pride in your business and its contribution to the local community by regularly sweeping your external work areas.
- Do not hose your outdoor surfaces into the gutter or drain. Recycle or dispose of the swept rubbish in your waste bins.
- Provide containers for cigarette butts in areas frequented by smokers.
- Ensure that all rainwater from roofs, yard areas, car parks, etc. is directed to the stormwater system and not connected to the sewer. Illegal connections of stormwater to sewers can result in overflows of raw sewage into our waterways.
- Check that any internal trade wastewater drains on your premises drain to the sewer not to stormwater. 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).
- Install litter collection baskets in stormwater drains on your premises.
- Ensure all water pollution controls (e.g. signs, speed humps, litter baskets etc.) are maintained on a regular basis. Indoor processing, manufacturing and workshop
areas
- Conduct all activities with the potential to pollute water (e.g. processing, manufacturing, workshop activities) within a roofed and bunded area or indoors. Liquid wastes and wastewater from these processes must not enter stormwater drains but should be either:
- recycled on-site
- treated and discharged to the sewer in accordance with the requirements of the local sewerage utility (A trade waste permit must be obtained first)
- collected in drums or tanks and removed by a licensed waste contractor for treatment and disposal at a licensed waste facility.
For premises licensed by the EPA, stormwater can be treated and discharged in accordance with the provisions outlined in the EPA licence. (This would generally not apply to small factories)
Floor washwater
- Install bunds across entrance and exit points of buildings and roofed areas to contain spills and washwater (Refer to Planning and General Information). Washwater must not enter the stormwater system but should be collected and either:
- discharged to sewer in accordance with the requirements of the local sewerage utility; or
- stored in drums or tanks and transported to a liquid recycling or treatment facility; or
- collected and recycled or reused on-site, e.g. for garden or lawn irrigation.
Spill containment
- Prevent any contaminants, spills or leaks from entering the stormwater drains. Make sure you have spill containment equipment such as absorbents, containment booms and brooms readily available. Refer to 'Hazardous Materials', for more information on spill procedures.
- Install first-flush collection 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. (Refer to Planning and General Information)
Outdoor work areas
- Separate relatively clean areas (e.g. driveways and car-parking areas) and relatively dirty areas (e.g. loading bays, material collection points, waste storage areas and yards).
- 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.
- Where practical, provide a roof over and a bund around any relatively dirty areas. Where this is not possible install a firstflush collection system to collect any contaminated water. (Refer to Planning and General Information)
Drum and tank storage
- Store all drums and tanks within bunded areas.
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.
Waste skip and bin storage 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.
Vehicle washing areas, driveways and car parking areas
- Provide a roof over and bunding around any area used to wash vehicles. Discharge any wastewater to the sewer in accordance with the local sewerage utility's requirements. (This may include maximising the recycling of washwater.)
Contractors working on-site
- Ensure any contractors or sub contractors working on-site are aware that no pollutants (e.g. paints, building materials and sediments) are to be tipped or washed into the stormwater system or placed where they may enter the stormwater system.
Plumbing
The trade wastewater drains inside your premises should all be connected to the sewer not 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
