Hydraulic design assessment process

You can apply for a hydraulics design assessment application in our Property Self Service Portal. You can work through the steps and questions and upload the necessary documents which will give us the information we need to make an assessment.

For all Hydraulics applications, you will need to submit plans that display the following:

• Location of our water and sewer mains
• Location of existing/proposed water connections, water meters and sewer connections
• Location of backflow prevention devices for domestic and/or fire
• Reduced Levels of sewer overflow gullies, floors and 1 in 100 year flood levels
• Internal domestic water supply
• Internal fire hose reel supply
• Internal fire hydrant/sprinkler supply
• Fire water storage air gap & over flow requirements
• Size of house drains

For complex developments, more documentation might be required. You can review these in the Hydraulic Plan Checklist

The submitted design is assessed by our technical staff to ensure it aligns with the requirements nominated in Hunter Water’s water and wastewater connection standards.

The assessment is mainly focused on:

• the size of property services and meters.
• the location of meters.
• installation of appropriate site containment backflow prevention devices and identified hazards.
• connection to the sewer system.
• the potential for discharge of trade waste to the sewer system.
• configuration of fire and domestic water storage tanks (including backflow prevention details).
• pump to sewer arrangements (where applicable).
• rain water tank re-use configurations.

Once the review has been successfully completed, we will email formal notification to the applicant.

It is important that all involved parties (hydraulic consultant, property owner and engaged licensed plumber) receive a copy of this formal notification to ensure visibility of the allowed works to be undertaken and the required applications and inspections.

Once the connection works have been completed and inspections confirming compliance undertaken, further requirements may be applicable relating to site containment backflow prevention device initial testing and certification, as well as trade waste agreement application.

Site containment backflow prevention device initial testing and certification is required for all testable site containment backflow prevention devices. Certification must be registered with us within seven days of device installation. This requirement will be nominated in the hydraulic design assessment approval.

Trade Wastewater Agreement application is required where the development incorporates trade waste discharge to our sewerage system. This requirement will be nominated in the Hydraulic Design Assessment approval. Whilst it is the responsibility of the property owner to submit this application the engaged plumber has a responsibility to promote this requirement as well.

A Hydraulic Design Assessment (HDA) is required under any of the following circumstances:

• where there are more than two residential units on a single lot.
• where it is an industrial or commercial development.
• where the development requires an internal fire service or alterations to an existing fire service.
• where there is potential for trade waste to be discharged to our sewerage system, or alterations to an existing trade waste installation.
• where there is the requirement to upsize or downsize an existing water meter.
• where a development (residential, commercial or industrial) requires an internally boosted water system.
• any development which is considered to be 'outside normal connection criteria'.
• where a development incorporates a private pressure sewer pump system.
• where a development incorporates multiple water metering systems.
• any alternative water supply other than rainwater.
• where a development incorporates a non-standard water and/or sewer connection.

Hydraulic Design Assessment applications may be submitted by the property owner, or a person that has authority to act on behalf of the property owner (e.g. plumber, hydraulic consultant, managing agent).

The design submission must be completed by a qualified person – generally a hydraulic consultant, or for minor submissions a licensed plumber may be suitable.

An accredited person is required to complete the design due to the fact that they are ultimately responsible for the operation and performance of the designed system.

Hydraulic plans need to be prepared in accordance with the:

• Plumbing Code of Australia
• Australian Standards AS/NZS 3500: Plumbing & Drainage
• Our Water Connection Standard
• Our Backflow Prevention Standard
  
• Our Wastewater Connection Standard
• Our Trade Wastewater Standard

The submitted hydraulic design/s need to clearly identify design standards as referenced in AS/NZS3500, or a 'Deemed to Satisfy' system.

'Deemed to Satisfy' systems require accompanying independent certification documentation and recognition from Building Commission – regulator of internal plumbing.