Perth rules for business sites
Trade waste needs a permit
Any business discharging trade waste to Water Corporation's sewers must, by law, apply for a permit first. Trade waste is any wastewater other than from offices or staff amenities.
Cooking usually means an arrestor
Water Corporation says businesses that prepare and cook food will generally need a grease arrestor. Some, such as childcare centres, need in-sink or floor strainers instead.
Backflow tested every 12 months
Testable devices at the property boundary, on medium and high risk sites and all fire services, must be tested at commissioning, after maintenance and every 12 months.
Big users need a water plan
Businesses using more than 20,000 kL a year must join the Waterwise Business Program, write a Water Efficiency Management Plan and report progress each year.
Trade waste and grease arrestors
Under the Water Services Act 2012, every food handling and preparation business must apply for a trade waste permit before it discharges anything to Water Corporation's wastewater system. The permit sets conditions for your site, including any pre-treatment.
A permit belongs to a particular owner, business name, location and process. Tell Water Corporation at least 14 days before any of those changes: buying an existing cafe can mean a new application or a permit transfer.
Grease arrestors must be installed by licensed plumbers to Water Corporation's trade waste requirements. Only a liquid waste contractor licensed by the environment regulator may clean one, at the pump-out frequency on your permit. You also need a hose tap with backflow prevention beside the arrestor, and records of every inspection and pump out.
Backflow at the boundary
Water Corporation requires containment protection on its water and fire services, matched to the property's risk rating, and fire services are rated medium risk whatever their size. Only a licensed plumbing contractor may install, commission, repair or maintain the devices; an accredited tester can test them.
Test reports go to Water Corporation online within 5 working days. Failing to comply can bring penalties of up to $5,000 and $500 per day. Our backflow testing page explains the device types.
Licences and care settings
WA requires a plumbing contractor's licence or permit number on ads, quotes, invoices and receipts, so check it against the WA Online Licence Search before work starts.
A lower limit of 45°C applies in aged care residential areas, patient care areas, the parts of childcare centres and schools used by children, and disability facilities. To hit it, the plumber must fit a thermostatic mixing valve or a thermostatically controlled tap.
What staff can do, and what needs a plumber
You can
- Keep the area around the grease arrestor clear for the waste contractor.
- Keep the trade waste permit on site, ready to show an inspector.
- Scrape plates into the bin and use sink strainers.
- Log every pump out, inspection and backflow test.
Leave to a licensed plumber
- Installing or altering a grease arrestor.
- Installing, repairing or maintaining backflow devices.
- Any change to drainage that alters what reaches the sewer.
- Hot water work in care settings, to the 45°C limit.
What we would do
Before fitting out or buying a food business in Perth, ask Water Corporation what trade waste permit and pre-treatment the site has, and diary the pump-out frequency and the backflow test date. Keep one folder with the permit, pump-out records and test reports, because those are what Water Corporation may ask to see. For the plumbing itself, we'll match you with a plumber who specialises in commercial jobs, holds a contractor's licence and knows Water Corporation's trade waste rules.