Trade waste charges

All discharges from commercial or service sites must comply with Bylaw 229 Wastewater Including Trade Waste and Domestic Wastewater, which places restrictions on discharge rates and strength of the effluent. Some discharges require a consent. For enquiries regarding trade waste consents please phone Council on +64 3 546 0200 and ask for the Trade Waste Officer.

Trade Waste Discharge Application Form (78KB PDF)

Charges

Trade Waste charges are based on the total costs recovered by the Council for conveyance, treatment, and disposal of the effluent regardless of which treatment system serves the premises.

There are three methods for how charges are decided:

Method A - The Measured Quality-Quantity Approach

The estimated total cost for the current financial year to be recovered by the Council through the Wastewater Activity Account for receiving, conveying, treating and disposing of wastewater within its district.

Method A applies where a trade waste or services customer’s water usage is over 10,000m3 per year or where trade waste BOD5 testing shows loads greater than 1.5kg/m3 and the cost of monitoring, testing and calculating the charges is likely to be less than half the trade waste charge for this category.

This cost is proportioned to the various stages of the service provided as follows:

Conveying

Capital charges and operating costs of sewers and pumping stations are allocated with respect to the rate of discharge. From 1 July 2024, the charge for Method A Conveying is $1176.45 (GST inclusive) per litre per minute.

Treatment

Capital charges and operating costs for wastewater treatment and disposal are allocated with respect to Biochemical Oxygen Demand ('BOD') 5 loadings. From 1 July 2024, the charge for Method A Treatment is $1,806.07 incl. GST per kg BOD per day. The charges in respect of special wastes are based upon the rate of discharge; and BOD 5 as hereinafter more fully dealt with and the charges for excess volume shall be based upon the first of these only, viz rate of discharge (except where hereinafter expressly provided).

The methods to be used for determining the rate of discharge and BOD 5 shall be as follows:

Rate of Discharge

The rate of discharge from any trade or service premises shall be deemed to be the average rate (in litres per minute) at which discharge is made - measured every three months with the waste stream sampled over four days each of twenty-four consecutive hours duration, which are reasonably representative of peak conditions during each financial year or over such lesser numbers of periods as may be agreed between the Council and the discharger.

Biochemical Oxygen Demand

The amount of BOD 5 for which any trade or service premises is chargeable shall be calculated in accordance with the results of analysis of samples collected by the Council proportionally to flow every three months with the waste stream sampled over four days  over periods of 24 consecutive hours on eight occasions that are reasonably representative of peak conditions during each financial year or on such lesser number of occasions as may be agreed between the Council and the discharger. The analysis shall be carried out on a shaken proportionate sample, which shall be analysed by the standard five day BOD 5 test.

The charges payable to the Council by owners of trade or services premises in respect of the receiving, treatment and disposal of trade wastes discharges from their respective trade premises shall, subject to the other provisions of the Wastewater Bylaw be calculated in accordance with the following basis:

Conveying based on rate of discharge per litre per minute. Treatment based on BOD 5 testing per kilogram BOD per day.

A wastewater charge is set under Section 16 of the Local Government (Rating) Act 2002 to recover the costs required for Council's sewerage disposal system. This charge is levied to all units to which the Council's sewerage disposal service is provided. The commercial and service wastewater charge from 1 July 2024 is $160.02 (GST inclusive).

The total amounts calculated above shall be reduced by deducting the wastewater charge as follows.

This final charge is expressed D = (P 1 O + P 3 R) - E

In calculating such charge in accordance with this method, any domestic sewage, which is discharged from the premises affected shall be deemed to be trade wastes. Please note that the application of this formula does not entitle an owner to a rebate.

Should final information with regard to rate of discharge or BOD 5 not be available in respect of any period for which payment becomes due, the Council may assess a provisional charge which shall be payable as if it were the proper charge, provided that as soon as the proper charge can be calculated by the Council, notice shall be sent to the owner and any refund or additional payment as the case may be shall be made within one calendar month from the date of dispatch of such notice.

Method B - The measured quality-estimated quantity approach

Method B applies where a trade or services customer’s water usage is over 6,000m3 per year or where wastewater BOD5 testing shows loads greater than 1.5kg/m3 and the cost of monitoring, testing and calculating the charges as per Method A is likely to be more than half the trade waste charge for Method A.

The estimated total cost for the current financial year to be recovered by the Council through the Wastewater Activity Account for receiving, conveying, treating and disposing of wastewater within its district is assessed.  

This cost is proportioned to the various stages of the service provided as per Method ‘A’ above:  

Conveying

Capital charges and operating costs of sewers and pumping stations are allocated with respect to the rate of discharge. From 1 July 2024, the charge for Method B Conveying is $1,176.45 (GST inclusive) per litre per minute.  

Treatment

Capital charges and operating costs for wastewater treatment and disposal are allocated with respect to Biochemical Oxygen Demand ('BOD') loadings. From 1 July 2024, the charge for Method B Treatment is $1,806.07 (GST inclusive) per kg BOD per day. The charges in respect of special wastes are based upon the rate of discharge; and BOD as hereinafter more fully dealt with and the charges for excess volume shall be based upon the first of these only, viz rate of discharge (except where hereinafter expressly provided).  

The methods to be used for determining the rate of discharge and BOD shall be as:  

Rate of Discharge

The rate of discharge from any trade or services premises shall be calculated based on the estimated volume of effluent discharged from the property. The default for discharge will be 80% of water measured into the site from all sources unless another figure is agreed by the Chief Executive - based on an auditable trail of evidence for any alternative. 

Biochemical Oxygen Demand

The amount of BOD for which any trade or services premises is chargeable shall be calculated in accordance with the results of analysis of samples collected by the Council proportionally to flow every three months with the waste stream sampled over four days over periods of 24 consecutive hours  that are reasonably representative of peak conditions during each financial year or on such lesser number of occasions as may be agreed between the Council and the discharger. The analysis shall be carried out on a shaken proportionate sample, which shall be analysed by the standard five-day BOD 5 test.  

The charges payable to the Council by owners of trade or services premises in respect of the receiving, treatment and disposal of trade waste discharges from their respective trade or services premises shall, subject to the other provisions of the Wastewater Bylaw be calculated in accordance with the following basis:  

• Conveying based on rate of discharge per litre per minute. Treatment based on BOD 5 testing (per kilogram BOD per day).  

A wastewater charge is set under Section 16 of the Local Government (Rating) Act 2002 to recover the costs required for Council's sewerage disposal system. This charge is levied to all units to which the Council's sewerage disposal service is provided. The commercial wastewater charge from 1 July 2024 is $160.02 (GST inclusive).  

The total amounts calculated above shall be reduced by deducting the wastewater charge as follows.  

This final charge is expressed D = (P 1 O + P 3 R) – E 

In calculating such charge in accordance with this method, any domestic sewage, which is discharged from the premises affected shall be deemed to be trade wastes. Please note that the application of this formula does not entitle an owner to a rebate.  

Should final information with regard to rate of discharge or BOD 5 test not be available in respect of any period for which payment becomes due, the Council may assess a provisional charge which shall be payable as if it were the proper charge, provided that as soon as the proper charge can be calculated by the Council, notice shall be sent to the owner and any refund or additional payment as the case may be shall be made within one calendar month from the date of dispatch of such notice. 

Method B customers can also install the appropriate effluent volume measuring equipment and become a Method ‘A’ wastewater contributor if they choose to. The volume and effluent strength charges will be as per method A.

For a limited number of activities – typically those where it is not possible to use a single % of ‘water in’ to reflect categories owing to very high levels of water used for processing or irrigation and highly variable levels of on-site wastewater produced Council will work with the activity owner and make an assessment of the expected discharge of effluent from the site. This will be charged at the closest appropriate rate taken from the trade waste ’A’/’B’/’C’ charges. Agreed volumes will need to be based on verifiable results and any activities in this category will need to be approved by the Chief Executive. Initially, all trade waste ratepayers pay the wastewater rate that is then deducted from the trade waste charges. Any surplus is not refunded. The deficit is the payable trade waste charge.

Method C - The Quantity Approach

For all other trade or service premises that do not fall under Methods ‘A’ or ‘B’, and for hotels, motels and camping grounds, the trade waste charge is based on the volume of effluent assessed as being discharged from the premises. This effluent volume is calculated by multiplying the volume of water supplied into the premises by a correlation factor. The correlation factor is usually set at 0.8 unless another figure is agreed. It is assumed that 80% of the water that is distributed to a commercial or service property is subsequently discharged as wastewater. The trade waste charge is then calculated using a combined conveyance and treatment rate. This rate is determined annually by dividing the estimated cost of operating the sewerage system for the coming financial year by the average of the previous three year’s total effluent volume. To arrive at the final rate the calculation above is then increased by 15% to reflect the greater complexity of trade waste discharges when compared to residential discharges.

The trade waste charge shall be calculated as follows:

D 1 = (W x F x C) - E

Trade Waste Discharge Application Form (78KB PDF)

For a limited number of activities – typically those where it is not possible to use a single % of ‘water in’ to reflect categories owing to very high levels of water used for processing or irrigation and highly variable levels of on-site wastewater produced Council will work with the activity owner and make an assessment of the expected discharge of effluent from the site. This will be charged at the closest appropriate rate taken from the trade waste ’A’/’B’/’C’ charges. Agreed volumes will need to be based on verifiable results and any activities in this category will need to be approved by the Chief Executive. Initially, all trade waste ratepayers pay the wastewater rate that is then deducted from the trade waste charges. Any surplus is not refunded. The deficit is the payable trade waste charge.

Temporary Hardship Concession for Trade Waste Customers

Customers in trade waste methods ‘A’ and ‘B’ who are experiencing significant financial hardship will be able to apply to the Chief Executive for consideration of a temporary reduction of the trade waste charges. Any application must be supported by auditable evidence of significant financial hardship that threatens the commercial viability of the business. The policy is restricted to a temporary reduction of charges only and will be based on allowing a time - based transition to full trade waste charges for the appropriate category over a maximum of three financial years.