Grease Trap Fact Sheet

What is a grease trap?

A grease trap is a chamber designed to separate grease and oil from waste water to prevent it entering the sewage system. Most restaurants, food processing companies etc, are required to have grease traps.

How does it work?

Within the grease trap, the waste water settles and the grease and oil float to the top. An outlet pipe below the grease layer allows the waste water to flow into the sewage system or into further one or two chambers to allow more grease to settle out.

What happens if a grease trap is not cleaned regularly?

If a grease trap is not cleaned regularly, the grease layer will build up and enter the sewage pipes. Blockages may result which cause great inconvenience and can be costly to repair. The relevant authority e.g. Watercare services may also intervene if blockages occur further downstream from your property. It is a requirement of most Sewer Discharge Consents, that grease trap be cleaned regularly.

How often should a grease trap system be cleaned?

This can vary greatly and depend on the size of the grease trap and the volume of waste water and grease being discharged through it. However, on average, grease traps need cleaning every 2-3 months. High use restaurants and food processors may need to have their grease traps cleaned every week or fortnight. Reputable contactors can schedule the cleaning of your grease trap on a regular basis and can monitor its condition to determine whether it needs to be done more frequently or less frequently.