Sewer Charges

Sewer charges for business customers are made up of:

Fixed Sewer Service Charge

Fixed sewer service charges fund most of the cost of operating the sewer system.

The sewer service charge is calculated using the following equation:

(Meter connection charge by meter size x Sewer Discharge Factor %) + Deemed Usage

The Sewer Discharge Factor (SDF) represents the proportion of metered connection which is equivalent to the residential base sewer service charge of $635.85 per annum.  

Meter Size

 Meter Connection Charge (per annum)   

 Deemed Usage

20mm*  $758.51 $80.40
20mm**   $758.51 $80.40
25mm  $1,185.18 $80.40
32mm  $1,941.78 $80.40
40mm  $3,034.04 $80.40
50mm  $4,740.70 $80.40
65mm  $8,011.76 $80.40
80mm  $12,136.16 $80.40
100mm  $18,962.75 $80.40
150mm  $42,666.18 $80.40
200mm  $75,850.98 $80.40
250mm  $118,517.19 $80.40
300mm  $170,664.75 $80.40
350mm  $232,293.69 $80.40

* The related meter connection charge applies where the property has a single billable metered connection of 20mm.

** The related meter connection charge applies where the property has multiple 

Sewer Discharge Factor (SDF)

What is the Sewerage Discharge Factor percentage?

The Sewer Discharge Factor (SDF) percentage is relevant to non-residential properties for calculation of fixed service and sewer usage charges. it does not apply to residential properties.

How is the SDF percentage determined?

For non-residential properties, the SDF have been broad banded into five bands. A property will fall within one of the bands, depending on the use to which the property is being put, and therefore the likely amount of water being discharged to the sewerage system as wastewater. Properties discharging similar amounts of wastewater are banded together.

Each SDF band then has an allocation midpoint. The midpoint allows for consistency with charging the apportioned usage for all customers who fall within the defined band. The banding methodology of SDF's provides categorisation for non-residential customer types whilst allowing for the variability in the volumes of sewer discharged that will always exist event within similar business types.

A small number of large industrial customers may be required to have a dedicated meter installed to measure all wastewater discharge to the sewerage system.

Table 1 SDF Categories and Band Midpoints


SDF Band

Midpoint of Band

Deemed Discharge Flows

Customer Type

1 0% 0% No discharge to the sewer system No Connection to the Sewerage System
2 1% - 25% 10% A small proportion of metered water is discharged to the sewerage system Typical enterprises include Nurseries and market gardens
3 26% - 50% 35% Around half of metered water is discharged to the sewerage system Typical enterprises include licensed clubs with catering facilities and substantial external watering eg. bowling greens
4 51% - 75% 60% A significant proportion of metered water is discharged to the sewerage system Typical enterprises include a public swimming pool with showering/toilet facilities and external watering.
5 76% -100% 85% Most, if not all metered water is discharged to the sewerage system Typical enterprises include restaurants and hotels.

What is the process for having the SDF percentage reviewed?

A property owner may request a review of the SDF percentage if they believe that it is in the wrong category. Any request for review is to be made in writing and must include adequate supporting evidence to substantiate how the customer has measured or calculated the actual volume of wastewater discharged to sewer to support a change in category.

If no measured or valid calculated data is available, the property owner at their own expense may choose to install sub-meter(s) to isolate and measure the wastewater which is discharged to the sewerage system from the usage which is used in production and/or externally. This meeting configuration would need to be initially verified by Hunter Water to ensure the capture of internal and external usage is accurate. This option would require the capture of the measured data over a twelve month period to account for seasonal variation in usage patterns. Should the outcome identify the SDF to be in a different category, the SDF percentage will be set at the midpoint of the appropriate band.

A request for review with supporting evidence can be made in writing to the following:

Team Leader Meters and Billing

PO Box 5171


or by email to  

When will the new SDF be adjusted on the account?

For new or re-developed commercial or industrial properties the SDF will apply from when the property is connected to the sewerage system or from when the re-development of the property confirming the type of business use has been verified.

Any approved change to the SDF midpoint as a result of a review will commence from the start of the bill cycle that the written application was received and the account adjusted accordingly.

Sewer Usage Charge

A sewer usage charge which is based on the volume of wastewater assessed to be discharge in to Hunter Water sewerage system. For business customers, this is calculated using the same SDF as applied to sewer service charges. The current charge is $0.67 per kilolitre of water used.

All non-residential properties that are individually metered receive a daily discharge allowance of 0.233 kilolitres per day which is deducted from the sewer usage. Non-residential customers that share a common meter (e.g. strata developments) will only receive one discharge allowance on the common meter for the entire premise and the amount for each unit is distributed by unit entitlement percentage.

Environmental Improvement Charge (EIC)

An EIC, which contributes to the cost of providing sewerage to established but unsewered areas in the Lower Hunter. The current charge is  $41.01 per annum.