If you are working on a public or private site near public utility pipes, you will most likely need a resource consent and engineering approval from the Auckland council as well as a Works Over approval from Watercare. As per Water Supply and Wastewater Network Bylaw 2015, the design of a structure shall protect the public water supply network and wastewater network from possible damage, misuse and interference. It also must not harm the environment or the safety of the people using the water supply.
Typical projects that need said approval are subdivisions, major developments and multi-lot projects. But in general, this requirement covers any project that includes building over a pipe, working close to a manhole and trenching of services.
The Works Over approval is given on the basis that the owner acknowledges all risk associated with repair or replacement works on the pipeline and future maintenance. On the other hand, Watercare assumes no risk or responsiblitity concerning the building, engineering or legal work associated with the application, the work itself and any consequences arising from future works (if any).
So if upon review of your application, Watercare finds any damage to the pipeline within your site plan, you will be asked to carry out sewer repairs or replacement. You may need to provide an initial CCTV inspection survey along with your application, for this purpose.
- The work must be carried out by a licensed/registered drainlayer certified by the Plumbers Gasfitters Drainage Board (PGDB). A certified drainlayer would work to comply with Watercare’s requirements for your particular building project.
- The drainlayer must secure an authorisation from Watercare to work on the public utility network. The approval to access and/or connect to the wastewater network must be applied for and granted prior to commencing work. To apply for this authorisation, you will need to provide a copy of your approved Works Over pack.
- Once some or all of the work have been completed, your drainlayer should provide a CS3 form with an as-built plan of the completed work. These will be sent to compliance @water.co.nz.
- One all works are complete, a final CCTV inspection must be submitted to ensure that the pipe has been repaired and none of the other pipes were affected.
Under normal circumstances, building over or adjacent to a public drain isn’t permitted. Nevertheless, dispensation is given as along as specific conditions are complied with and the building work is completed according to the approved plans.
The following are the specific conditions stipulated by Watercare:
- Existing asset/ wastewater connection
The property owner is responsible for identifying the exact location of all Watercare pipes and structures (including connections) onsite to ensure all clearance requirements are met as per Watercare Engineering Standards. Any blockages and/or damage resulting from inability to identify and protect these assets will be shouldered by the owner at his own cost.
As service connections are not allowed under the building footprint, the owner must see to the relocation of existing connections to a minimum 1m clearance from the building. Moreover, all work involving the existing wastewater service connections must be compliant with Watercare’s compliance statement policy. A separate ‘new connection application’ is required for all new wastewater connections.
To protect the wastewater pipe, foundation design must provide adequate support and protection for the structure on top of the pipe and the bridging piles must absorb the structural load of the building. All excavated sites within the 45o filed of the influence must be shored or retained properly to avoid damaging the sewer pipe line. The bottom of the foundation slab or beam must be compliant with Watercare Code of Practice Drawing WW 27. At any time throughout the works, Watercare’s ability to maintain and/or replace the pipe must not be impeded.
- Piles/retaining wall posts
There should be at least 1 metre horizontal clearance between the foundation piles and the face of the pipe. The piles must be in a predrilled hole and founded below the 45o zone of loading influence. Driven piles are not allowed unless they are over 5 metres horizontally from the face of the pipe.
For keystone retaining wall foundation, a minimum vertical clearance from the top of pipe is required as per Watercare Code of Practice Drawing WW 27.
A council structural engineer must inspect bridging details and calculations before issuing a Building Consent and/or EPA.
- Driveway/vehicle crossing
A minimum of 900mm vertical clearance must be maintained from the top of the driveway slab to the top of the water and wastewater pipes. Heavy machinery must NOT be parked or operated directly above Watercare assets. Surface mounted assets must be cordoned off to avoid traffic movement over them or must be protected with 30mm steel road plates at construction vehicle crossing points. Any exposed mains must be cover with 150mm layer of SAP7 cushion prior to backfilling. Backfill must be compacted in 200mm layers to achieve maximum density.
During the course of the work, the owner must ensure all manholes are accessible at all times. The minimum clearance from any structure is 1 meter from the outside edge of the manhole chamber.
- Damage to Watercare asset
If in case the public water or wastewater line is damaged during construction, the owner must immediately advise Watercare and seek approval for repair work.
- Post construction CCTV
A final CCTV inspection survey and log must be submitted to Watercare once all of the works have been completed. This is to ensure that no defects/damage to the sewer pipes have been incurred during construction. If any issue is found on the post construction CCTV, the repair and all associated costs must be borne by the property owner.
If you need a reliable drainlayer to carry out Watercare compliant sewer repairs, get in touch with Euro Plumbing on 0800 832 638. We have the expertise and equipment for the job, and we’ll take care of your repairs so you can proceed with your building project ASAP.