Full retention separators

Registered white Rewatec logo.

Guard against hydrocarbon pollutants entering the environment, even during storm surges, with our robust and reliable full retention separators. 

Cutaway view of a Rewatec full retention separator

What are full retention separators?

Full retention separators, sometimes known as petrol interceptors, are used where there is a risk of regular oil contamination and a foreseeable risk of significant spillages. They are designed to treat the full flow that can be delivered by a drainage system. This is normally generated by rainfall intensity of 65mm per hour, often referred to as ‘torrential’.

Example applications

  • sites with high risk of oil contamination
  • fuel storage depots
  • refuelling facilities
  • vehicle maintenance areas/workshops
  • where discharge is to a sensitive environment


Rewatec full retention separator

If it is considered to be an acceptable risk not to provide full treatment for high flows, visit our bypass separator page for a solution that meets your needs. 

How do full retention separators work?

Step 1

Contaminated surface water from heavy rainfall, or a significant fuel spillage, enters the separator via the inlet. Pollutants that have a low density, such as oil and diesel, separate and rise to the surface of the water.

Step 2

The decontaminated water then passes through the coalescing filter before being safely discharged to the environment via the outlet.

Step 3

Any remaining pollutants are retained in the separator until they are removed by a qualified professional. A high level alarm within the separator, notifies the user once the specified oil level is reached.

Rewatec full retention separator operation


All Rewatec full retention separators have an automatic closure device (ACD) fitted as standard. This is compulsory for all compliant full retention separators and prevents accumulated pollutants flowing through the unit when the maximum storage level is reached.

Full retention separator maintenance

We have a network of local service partners to maximise the life of your Rewatec full retention separator and to provide years of reliable operation. If you require commissioning, servicing or maintenance for your system, contact us for a free quote today.

We stand by our products

For over 50 years, we have proudly developed sustainable and long-lasting products that make a real difference for our customers, our professional partners, and, above all, our planet.

Our experience in the industry allows us to give you a complete 25 year warranty for Rewatec full retention separators.

Rewatec 25 years warranty

Training for professionals

​​​​​​At Premier Tech we provide a full range of training programmes to fully meet the requirements of our professional partners. If you require product functionality guidance or a more detailed training course for installations, we can provide a solution to meet your needs.

Contact us for more information

Technical information

Our Rewatec full retention separators can be installed for drainage areas ranging from 222m2 to 47,222m2.

Rewatec CNS full retention separator specification table


Here at Premier Tech, we understand that some sites require different pipework sizes to fit with the specific needs of the overall drainage system. If you have a requirement for larger or smaller pipework, or if you require a separator for a drainage area ranging from 38,889m2 to 47,222m2, contact us for a bespoke solution that meets your needs.

Available products

Our Full retention separators are available in a range of sizes to suit all requirements.



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