Bypass separators

Registered white Rewatec logo.

Protect your property, location and the environment by choosing Rewatec bypass separators, designed specifically for small spillage occurrences or where the risk of a spillage is low.

Cutaway view of the Rewatec bypass separator.

What are bypass separators?

Rewatec bypass separators (formally Conder bypass separators) are for use with surface water drainage systems and are designed to prevent hydrocarbons such as diesel, petrol and engine oil from mixing with surface water and entering drainage systems.

They are used to fully treat all flows generated by rainfall rates of up to 6.5 mm/hr. Separators are used when it is considered an acceptable risk not to provide full treatment for high flows, such as low risk applications.

Example applications

  • car parks
  • roadways and major trunk roads
  • light industrial and goods yards
Rewatec bypass separator.


How do bypass separators work?

Pollution prevention is a critical part of sustainable drainage systems and statutory regulations are in force to control the discharge of hydrocarbons such as oil or fuel.

Rewatec bypass separators have been designed to treat all flow rates up to the designed nominal size. Any flow in excess of the nominal size is allowed to bypass the separation chamber, thereby keeping the separated and trapped oil or fuel safe.

Rewatec bypass separator cut away view

Step 1

During the early part of a rain storm, all the contaminated water flow passes through the sediment collection chamber and enters the separation chamber through a patented oil skimming and filter device.

Step 2

All the oil then proceeds to the separation chamber where it is separated to the Class 1 standard of 5 mg/L and safely trapped.

Step 3

As the rainstorm builds up to its maximum and the level of oil contamination reduces significantly, the nominal size flow continues to pass through the separation chamber and any excess flow of virtually clean water is allowed to bypass directly to the outlet.

If there is a regular risk of contamination from oil or a foreseeable risk of significant spillages, visit our full retention separator page for a solution that meets your needs.

Bypass separator maintenance

We can provide a range of services to maximise the life of your Rewatec bypass separator and to provide years of reliable operation.

Contact us to find out more

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 bypass separators.

Rewatec 25 years warranty

Visit our site

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

Contact us for more information

Technical information

Our Rewatec bypass separators can be installed for drainage areas ranging from 1,667m2 to 277,778m2.

Rewatec bypass 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, contact us for a bespoke solution that meets your requirements.

Available products

We offer a complete range of Rewatec bypass separators to meet your needs. Wherever your site, whatever the regulations.



Free quote

We are here to help. Request a quote today and our team of experts will be in touch.

Request a quote