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Equivalent Tenements Explained

An Equivalent Tenement (ET) is a measure of the load a property places on the sewerage system. One ET is considered to be the sewage discharge from an average single residential house, under dry weather flows. This has been determined to be 200kL/ET/annum. ET rates for different land uses are calculated as being a factor of this average sewage discharge rate.

There is and will be variability in peak demands for residential use due to household occupancy rates and internal water use efficiency (which is dependent on the presence of water meters and two part tariffs, the penetration of demand management principles and the extent of water efficient appliances and fixtures), however the application of a standard rate for residential properties is cost effective and common practice.

In relation to non-residential properties, different ET rates are applied to various property attributes, including building area, land size, number of occupants, general public entertainment facilities, hospital beds and amenities. These ET rates and attributes are then used to undertake an assessment of the number of ETs for that property.

Where a property has multiple activities on the land parcel the ET rates and assessment are based on each specific type of activity.

High-level ET categories applied by TasWater include:
Standard occupancy
o includes residential dwellings, together with units, flats, apartments and granny flats, regardless of the number of bedrooms and the density of the dwelling (ie number of storeys)
Accommodation (permanent)
o includes accommodation dwellings or rooms that are occupied permanently or semi-permanently, but are generally developed on land zoned for commercial purposes; such as Caravan/Mobile Home Park (with permanent occupation), Boarding House, Nursing Home and Self Care Retirement Unit
Accommodation (short term)
o includes accommodation dwellings or rooms that are occupied temporarily, and are generally developed on land zoned for commercial purposes; such as Caravan Park, Motel, Backpackers, B&B and Serviced Tourist Apartment
Accommodation (medical care)
o includes medical care accommodation, occupied temporarily, such as Hospital and Hostel (medical)
Business (excluding food preparation)
o includes commercial/business developments such as a Single Shop, Supermarket, Shopping Centre and Office
Food preparation
o includes commercial/business development associated with food preparation, such as Restaurant/Cafe, Takeaway/Fast Food and Catering
o includes commercial/business development associated with entertainment, such as Pub/Bar, Licensed Club, Theatre, Function Centre and Marina
Sporting/spectator facilities
o includes commercial/business development associated with sporting and spectator facilities, such as Amenities & Indoor facilities, Swimming Pool and Bowling Alley
Community facilities
o includes commercial/business development associated with community facilities such as Child Care, Education, Correctional Centre, Church, Community Centre and Public Amenities Block
o includes industrial activity associated with Food Manufacture, Metal Processing & Manufacturing and Services (including laboratories and industrial laundries)

This list of categories is not exhaustive and consequently TasWater has included the ability to assess on an ad hoc, case by case basis if the circumstances warrant.

It should be noted that discharge of non-domestic liquid trade waste is recouped separately through the application and payment of trade waste charges.

The NSW Water Directorate guidelines indicate it is preferable to apply localised ET figures as there are variances in differing jurisdictions. TasWater has adopted statewide ET rates, consistent with the application of postage stamp pricing across the state, and made adjustments to some rates to best reflect Tasmanian circumstances19. TasWater undertakes to publish, on its website by 1 July 2015, justification for each instance where it has adopted ETs that differ from those published in the Water Directorate’s guidelines. Click here for ETs that differ from the Water Directorate's click here.

ET assessment process
With respect to assessing a customer’s property calculated ETs, the following steps are undertaken:

1. A combination of data sources such as site visits, local knowledge, google maps, direct customer contact and council data, are used to ascertain the property type and associated property attributes. ETs for identified non-residential customers, eg commercial, industrial, primary industry, and community services, to be determined based on their respective category and, within that category, the other relevant parameters including number of beds or rooms, number of staff and students, and gross floor area and/or applicable amenities.
2. Attribute a default one (1) ET to all identified standard residential customers.
3. Identify customers who have a property within Serviced Land that is not physically connected to TasWater’s infrastructure but which has the ability to connect. While the property will have a minimum of one ET, these customers will be charged at 60 per cent of the standard ET rate for a residential dwelling.
A schedule of the ET rates for different industries/property use types is provided here.

ET rates and sewerage charges
ET assessments are used to calculate a customer’s fixed sewerage target charge. The fixed sewerage charge covers costs associated with treatment and disposal of domestic sewage.
A customer’s fixed sewerage target charges increase proportionally with the ET assessment, with non-residential properties charged based on the load they could potentially place on the sewerage system relative to a single residential dwelling.
For sewerage charging purposes, no customer can be less than 1 ET, however if a property is within Serviced Land but not connected that customer will receive an unconnected sewerage service charge, which equates to 60 per cent of the full fixed sewerage target charge.
The practical application of the ET methodology means that if a property is deemed to be capable of discharging twice as much sewage into the sewerage system, it will be assessed as 2 ETs and the target price will be twice the standard fixed sewerage charge. Similarly, if the customer could discharge 50 times as much as a residential dwelling it will be assessed as 50 ETs and the target price will be 50 times the standard fixed sewerage charge.
For the purpose of calculating sewerage charges, the Economic Regulator has approved that a customer’s ET assessment will result in a minimum of one ET being applied, although ET rates for different property types may be less than one.

ET reassessment
TasWater has arrangements in place for customers to have their ET calculation reassessed if they believe it is inaccurate.
An ET reassessment may result in an increase or decrease in the ET rates and therefore the applicable target price. The new rates and target price will be applied to the customer’s account from the next billing period, with the charges transitioning (consistent with the approved price constraints) at the start of the next financial year.
If you believe that the data used to calculate the ET total is inaccurate.  Please contact us by email on with 'ET' as the subject heading or phone 13 6992.