Hāhei Wastewater Extension

Currently, the lots in the Wigmore area extension have on-site disposal systems. The scheduled project would include the following:

a) A low-pressure sewer network system with boundary kit connection from each lot.
b) The pressure sewer main will discharge into the existing wastewater pump station (WWPS) on Pa Road.

The Council will supply the following aspects of the system:

• Boundary kit to each property (*SUIP unit).
  a) A boundary kit in the wastewater connection refers to a pre-assembled set of components installed at the property boundary to facilitate the connection of a private wastewater system to the public sewer network.
• Pressure sewer main.
• Upgrade the existing Wastewater Treatment Plant (WWTP) at Pa Road to meet the additional demand from both Wigmore Area and Robyn Crescent extensions.

Each property owner, at their own cost, will need to:

• Install a single grinder pump with storage at a suitable low point within the lot.
• The newly installed grinder pump with storage will be privately owned and maintained by the property owner.
• The residential grinder pump will pump the wastewater through a pipeline to a boundary kit located at the lot boundary (within the road reserve).
• Decommission their existing on-site system.

Please refer to the typical drawings on this webpage for wastewater connection arrangement with boundary kit and details of grinder pumps. 

As with the Wigmore Area extension, the scheduled project for Robyn Crescent would include the following:

a) A low-pressure sewer network system with boundary kit connection from each lot.
b) The pressure sewer main will discharge into the existing manhole located at 35 Michelle Lane.

The Council will supply the following aspects of the system:

• Boundary kit to each property (*SUIP unit).
  - A boundary kit in the wastewater connection refers to a pre-assembled set of components installed at the property boundary to facilitate the connection of a private wastewater system to the public sewer network.
• Pressure sewer main.
• Upgrade the existing Wastewater Treatment Plant at Pa Road to meet the additional demand from both Wigmore Area and Robyn Crescent extensions.

Each property owner, at their own cost, will need to:

• Install a single grinder pump with storage at a suitable low point within the lot.
• The newly installed grinder pump with storage will be privately owned and maintained by the property owner.
• The residential grinder pump will pump the wastewater through a pipeline to a boundary kit located at the lot boundary (within the road reserve).
• Decommission their existing on-site system.

Please refer to the typical drawings on this webpage for wastewater connection arrangement with boundary kit and details of grinder pumps.

Key design assumptions used to develop the design are as follows:

• The size of the wastewater network has been based off historical understanding of peak flows, during the peak occupancy period. This relates to an average peak period occupancy of five people per lot.
• The wastewater network was also sized to handle possible future growth scenarios such as increased occupancy levels, and potential subdividing or infilling.
• Allowance has been made for connecting an additional 80 properties located south of Pa Road into the pressure sewer network in future. For the avoidance of doubt, this is not included in the below costings.
• The pressure sewer mains will be installed by trenchless techniques such as horizontal directional drilling (HDD). This would have less disturbance caused by trench excavations and less surface (road/grass/walkway/driveway) reinstatement. Where HDD is not practical conventional trench excavation would be done.
• The pressure sewer main needs to cross Wigmore Stream at two locations and would be connected to existing bridges. The sewer would be installed inside a steel pipe to prevent damage that could cause leakage into the stream.
• Air valves, scour valves and flushing pits (to flush the system if required during low occupancy periods) will be installed to ensure maintenance and operation of the system. These will be located at appropriate locations within the road reserve.
• The existing WWPS on Pa Road will receive additional wastewater from these extensions. An underground tank will be installed to balance additional volume peaks to the WWTP.

In addition to the new wastewater network, the existing wastewater treatment plant, if required, will be upgraded to meet the Waikato Regional Council compliance limits for wastewater effluent quality.  

The estimated total capital cost for the wastewater extension to 88 properties (SUIP units) is $1,738,800.00+GST (Inflation adjusted)

This would equate to a per SUIP unit cost of $32,800.09+GST including the development contributions. The calculation is presented in the table below.

The final cost per property (each SUIP unit) can only be determined after conclusion of detailed design, tendering and construction of these works and all project costs are confirmed.

In addition to this, each property owner would need to pay for the installation of the grinder pump and pipeline connection to the boundary kit. This estimation is dependent on the location of grinder pump but is estimated to cost between $14,000 and $17,500+GST.

1. What would you pay

1.1   Capital Cost

The estimated capital cost of $19,759.09 for each property (each SUIP unit) can be paid after completion of the project as:

a) A one-off payment, or
b) A targeted rate over a maximum period of 10 years, which will also include interest and administration charges.
c) Alternatively, payment could be made by a partial upfront payment and payment of the balance (including interest and administration charges) through targeted rates.

These amounts will be payable on a per SUIP basis, meaning each Separately Used or Inhabited Part (SUIP) of a rating unit includes any part inhabited or used by a person other than the owner, and who has the right to inhabit or use that part by virtue of a tenancy lease, license, or other agreement (such as a separate dwelling, flat, or unit on a property that receives its own water/wastewater connection) will be charged individually.

This means that if your property contains multiple SUIPs as described above, it will be charged based on the number of those units, as each receives its own water connection.

1.2          Development Contribution charges

Payment of the estimated development contribution charges ($13,041) will only be required when the property (each SUIP unit) is connected to the wastewater network, after the capital project is completed. If you do not connect when the new network is available, then the development contribution charge (as at the date) would only be applicable if and when you connect in the future.

Development contribution charges are considered as a share of the cost of existing or planned network-wide infrastructure, like treatment plants, bulk mains, reservoirs, etc. in addition to the direct capital cost of the project. This ensures that growth-related costs are fairly distributed among those who create the demand, rather than by existing ratepayers for the wastewater service.

1.3          Wastewater Rates

a) If you connect to the network then from the time of connection, each property (each SUIP unit) will include the wastewater serviced rates, with annual rates proposed at $1,252.58 per annum. This is the current applicable rates but is subject to change as Council reassesses and sets it proposed rates each year.

b) If you decide not to connect then your property (SUIP unit) will be charged the wastewater serviceable rate at $939.43 per annum once the project is completed. This is the current applicable wastewater serviceable rates but is subject to change as Council reassesses and sets it proposed rates each year. Note that your property,
     i. Will still be liable for targeted rates covering the capital cost of the project
     ii. But will not be charged for the Development Contributions.  (Note if you decide to connect at a later date, you will be required       to pay the Development Contribution charges applicable at that time that you connect.)

Please refer to the attached FAQ sheet for answers to other common questions you may have regarding this.