Drainage And Sewer Repairs

Drainage repairs can cost unnecessary thousands of dollars if not investigated and diagnosed correctly. Having the right experience and tools is a key factor in saving you cash!

Repairs can include:

  • Damage to pipework caused by tree roots, age or external force.
  • Repair or replacement of older style pipework such as earthenware, ceramic or steel pipe systems
  • Replacement of old or damaged overflow relief gullies (gully traps)
  • Driveway channel repairs and replacements
  • Sewer and storm water blockages including CCTV
  • Water tank repairs and pipe systems
  • Concrete sewer and stormwater pipe repair
  • All domestic and commercial drainage and stormwater repairs

Our repair services include rearrangement of existing sewer and stormwater drainage systems to accommodate renovations, home extensions and drainage upgrades.

Sometimes it not necessarily a repair that is required but rather a re-arrangement or modification to existing sewer or stormwater systems. This is very common with renovations, add-ons or landscaping applications.



Gully traps receive discharge from waste water fixtures. In the event of a drainage system becoming blocked, gullies also provide a point at which sewage can overflow outside a building instead of building up inside the pipe system and overflowing at a fixture inside the building (for example overflowing out of your shower or toilet)Every residential building must have at least one gully trap which:

  • Has its overflow rim at least 150 below the overflow level of the lowest fixture served by the system
  • Is located within the legal boundary of the land on which the building stands.

The construction and layout of the gully traps must comply with the image to the right.

Gully traps must be constructed:

  • To prevent surface water from entering
  • So that the grate will lift to allow surcharge
  • With at least one discharge pipe to maintain the water seal


In New Zealand drainage systems must be vented to reduce the build-up of foul air within the drains and:

  • Every main drain must be ventilated by a pipe of 80 mm (NZS) or 50 mm (NZS/AS) diameter that terminates in accordance with the termination pipes standards to the open air.
  • Every branch longer than 10 meters me also be ventilated in accordance to the standard
  • Vent pipes must be located so that the length of the drain upstream of the vent is less than 10 meter.
  • Vent pipes must be located so that they are downstream of the discharge pipe that is closest to the head of the drain (this will allow for regular flushing at the point where the vent connects with the drain)

Vent pipes as critical to ensure a full operating drainage system. If you are increasing the size or modifying your drainage system, make sure you make allowances for venting. A poorly vented drainage system can result with the following:

  • Blocked drainage pipes
  • Noisy sounds in the drainage system
  • Risk of smells and sewage within the building envelope
  • Fixtures not discharging properly (Toilet doesn’t flush properly, need to flush multiple times)
  • Gurgling noises one fixture when other fixtures connected to the system are being used.

Drainage NZ know all about how important venting and can provide simple solutions to install or repair your existing drainage venting scenarios.