What is a vacuum pit and how does it work?

Vacuum pits or vacuum systems work differently to conventional sewers. The wastewater from your house flows into a retention pit or vacuum pot. When the water in the pit reaches a certain level, a vacuum valve opens and sucks the waste into the sewer main.

Where are vacuum pits currently in place across Auckland?

Clevedon and Kawakawa

What’s involved in this kind of sewage system?

This type of sewage system has two important features - a gully and the low-level vent. The gully is a round grate, set in concrete outside your house. It provides a relief point in case the sewer blocks up. The wastewater will flow out of the gully, rather than back up into the house. The low-level vent provides an air relief valve for the system. This prevents the system affecting the plumbing fixtures in your home. The vent is located at the front of your house and looks like a bendy piece of pipe with a little hat on it. It should be located 300mm above the ground. Keep the area around the vent clear and do not damage the fixture.

How do I look after my vacuum pit?

This sewage system relies on biological processes to treat wastewater. This means, bacteria are used to mulch away at the nutrients in the waste and render it inert. Medicines, particularly antibiotics can kill these bacteria, so if you tip these down the toilet you will damage the treatment process.

You need to manage what you put down your toilet as this has a big effect on the efficiency of the system. Do not place solid objects down the toilet – metal, plastic, and textile material. If you place objects such as toothbrushes, kids toys etc down the sewer they can become lodged in the retention area. Larger items will fill up the bottom of the pit, smaller items may get sucked up and jam the vacuum value. As a result, you will notice a rattling, rumbling sound which may travel back along your household plumbing.

Please only put the three p’s down your vacuum pit – paper (toilet paper), pee and poo. Click here to find out more about what not to flush.

Where will it be located?

Click here and see an example of where the pit will be located (on page 2).

What does a house to vacuum pit connection look like?

Click on the diagram to see the typical layout of a house to vacuum pit connection.

What do I do if I block or damage my vacuum pit?

Please contact our service line immediately on 09 442 2222 option 1.

Additional information

For drainlayers working in Clevedon, click here for technical information on vacuum pits.