CSG’s interceptor care checklist

20 November 2025 by CSG

Interceptors are drainage systems found at numerous commercial and industrial sites, including car parks, car washes, petrol station forecourts, construction sites, factories and vehicle maintenance areas.

They prevent oil from polluting the environment or discharging into the sewer.

Since December 2023, the Environment Agency has had the power to impose unlimited fines, or even pursue criminal prosecution, if pollution occurs. There would also likely to be clean-up costs and increased insurance costs.

If you have interceptors at your site, follow this simple checklist to ensure you stay on the right side of the law:

Inspection

The EA says you must check your interceptor regularly. An inspection every three to six months should include:

• Checking the area around the interceptor –
  • Is the interceptor accessible?
  • Are there any damaged areas that could cause an issue?
  • Can you lift the manhole?
• Check the accumulation of silt, oil and any other substances –
  • If there is a build-up, you should consider a clean and empty. This is especially important after heavy rain.
• A visual check of any mechanical parts associated with the interceptor eg. probes.

Servicing

It is advisable to have your interceptor serviced every six months by a qualified engineer in accordance with the manufacturer’s instructions.

An interceptor service should include:

• Checking the filters and, if necessary, repair or replace them.
• Servicing the electrical systems (eg. volume alarms and automatic closure devices)
• Examining manholes, pipework, gullies and other water-draining infrastructure around the interceptor.

Cleaning

• Clean and empty your interceptor when there is a build-up of oil or silt in the system. You should also arrange an empty if the alarm sounds, or in the event of an oil or chemical spill.
• This must be done by a licensed hazardous waste carrier, like CSG.
•  You should keep records and log any inspections and services. Any incidents that have occurred within your system should also be noted.

Customers with a long-term plan for cleaning and servicing their interceptor can save money while protecting the environment. To get help with your interceptor, contact 0808 134 6914 to learn how CSG can assist.