There are mainly two types of sewerage systems/services in Malaysia. The premises' sewerage systems are either connected to a public sewage treatment plant or have an individual septic tank.

IWK is mainly responsible for operating and maintaining the public sewage treatment plants and network of underground sewerage pipelines.

The services are rendered through the company's 18 Unit Offices/Customer Service Centres located throughout the country, except Johor Bahru, Kelantan, Sabah and Sarawak. Customers can also pay their Sewerage Services Bills at these centres.