Inflow & Infiltration Programmes

We can supply a ‘road map’ so councils can navigate the complexity and implementation of an inflow and reduction programme.

Water entering into sewer systems through inflow and infiltration (I/I) can significantly reduce the performance of wastewater systems. Increased sewer flows due to inflow and infiltration can result in overflows and negatively impact on the performance of pump stations and wastewater treatment plants.

Developing a programme to reduce inflow and infiltration can be complex, involving technical, regulatory, budgetary and community interests. To be successful both the private and public sections of the wastewater network must be addressed.

Since 2002, ProjectMax Ltd has established specialist knowledge and experience, in this area, working with councils to help them develop successful inflow and infiltration reduction programmes. In 2008 the “Wastewater Rehabilitation Partnership” Agreement was established between North Shore City Council and ProjectMax, as part of North Shore City’s $200 million dollar ProjectCARE, helping to protect the environment by minimising wastewater discharges and working with people in the community.

ProjectMax can help you develop a road map for the assessment, analysis, programme development, method selection and legal and financial implementation that will make it easier for you to decide how to implement an inflow and infiltration reduction programme.

For further information, contact: Blair Telfer



Work Area
1. Investigations

Problems that arise:

  • Faults overlooked or inaccurately recorded.
  • Areas of major faults avoided because they are too hard.

Benefits of using ProjectMax:

  • Investigations accurate and complete.
  • All faults identified.
2. Management of private drainage works

Problems that arise:

  • Mountains of paper.
  • Difficult to track what repairs are required, what notices have been issued and which properties have been repaired.
  • Defects not repaired.
  • Target reductions in leakage not achieved.

Benefits of using ProjectMax:

  • Typically half of all leakage occurs through private drainage.
  • PML has tools and software to record/track works that improve liaison with property owners.
  • Help ensure that all faults are identified and repaired.
3. Integration with GIS and asset management systems

Problems that arise:

  • Investigation information considered in isolation.
  • Pipe material, length, size, manhole position not updated in GIS and asset management software.
  • Inspections cannot be retrieved in the future data is lost.
  • Repeat inspections required.

Benefits of using ProjectMax:

  • Information from CCTV and other investigations used to improve the accuracy of GIS and asset management data.
  • Improved accuracy of information enabling better decisions in future.
  • Inspections can be easily retrieved in the future.
4. Selection of repair/rehabilitation method

Problems that arise:

  • Very few techniques considered.
  • Suitable solution may not be identified.
  • If solution identified it may not last, may not be cost effective or achieve the desired result.
  • May cause unnecessary disruption.

Benefits of using ProjectMax:

  • Most appropriate repair/rehabilitation method selected for each particular circumstance.
  • Less disruption, cost effective, long lasting results.
5. Quality control

Problems that arise:

  • Faults in installation overlooked.
  • Problems develop in future.
  • Project viewed as a failure.
  • Future projects cancelled.

Benefits of using ProjectMax:

  • Established specifications and quality assurance systems that make sure that the repair/rehabilitation works meet the required standards