- Residential properties – 110mm drain non return valves
- Commercial properties – 150 mm drain non return valves
N.B. you may have more than one pipe leading to the drainage system.
The next step is to determine where you can install a drain non return valve. The easiest place to start is to look around your property for an inspection chamber, and lift the lid. If you are unable to remove lid yourself, please contact a drainage expert to help you. If you have an inspection chamber, count the number of in pipes into the chamber and assess the size of each pipe. In this case, you can install a retro fit non return valve. No tools are required and can be installed in minutes.