The $3.8 million system has been designed to cater for up to 3600 homes, according to MidCoast Water's chairperson Cr Linda Gill.

"This system has been designed with future developments in the Tea Gardens area in mind," Cr Gill said.

The system is three times as large as the second largest vacuum sewerage system in the southern hemisphere, which is located in Western Australia.

"Vacuum systems are becoming increasingly popular in Australia as they allow sewer pipes to be laid closer to the surface," Cr Gill explained.

"This is particularly helpful in water-charged ground, or rocky terrain which is difficult to excavate."

The Tea Gardens system is the third vacuum system MidCoast Water has been involved in, similar systems installed at Manning Point and Harrington.

Inside their homes, residents notice no difference between the vacuum system and a conventional sewerage system, as plumbing fixtures are exactly the same.

Wastewater from the homes flows into storage pits. One pit is shared by two or three homes.

When the pit is full, the vacuum mechanism is triggered and the effluent is sucked out of the pit to the main pumping station.

From here it is transferred to the Hawks Nest wastewater treatment plant, where it undergoes the usual processes.

"Vacuum sewerage systems also minimise wet weather infiltration, which leads to a reduction in the volume of waste water to be treated."

The new station is being constructed to cater for the significant growth expected in Riverside at Tea Gardens and Myall River Downs developments.

Design of the Tea Gardens system was completed in August 2005, with construction starting in December of the same year.

MidCoast Water expects the project to be completed early in 2007.