The Althon standard range of headwalls can accommodate pipework up to 2100mm. We can cast multiple pipe openings into our outfalls if required. As standard we will cast in the pipe openings 100-150mm above the spillway. However we are able to cast in the opening for the connecting pipe or pipes anywhere on the backwall or in the wingwalls (sidewalls). Drainage pipes discharging into open watercourses should be fitted with a concrete headwalls. Althon's standard concrete headwalls are fast and easy to install.

All Althon headwalls can be factory fitted with accessories such as outfall safety grilles, Kee Klamp® handrails, flap valves and penstocks. We are also able to provide additional precast elements, such as diffuser blocks, stepped baffle blocks, extended spillways with cascade panels and in some instances precast steps. We are happy to help design a precast concrete outfall & spillway to your site specific requirements.

Althon have the largest range of precast headwalls with associated accessories available in the UK. If you cannot find the product you are looking for please get in touch with us and we will be happy to assist. We are constantly uploading new ranges and new drawings to our website, we are confident we will be able to meet your spillway and outfall requirements.

If you require any assistance or more information please contact us by phone on 01603 488700 or by email

Brochures and Datasheets

Benefits of Althon Precast Headwalls

  • Headwalls are precast in controlled factory conditions
  • Precast headwalls can be manufactured to accommodate multiple pipe openings
  • Pipe invert level and opening can be specified to site specific requirements
  • Precast headwalls are fast, easy and safe to install
  • Precast headwalls do not require any on-site formwork or shuttering
  • We supply flap valves, penstocks and other flow control devices factory fitted
  • Headwalls supplied with Kee Klamp® handrails & fixing points cast in at the factory
  • We supply a range of outfall safety grilles and trash screens factory fitted
  • We have headwalls that comply with Sewers for Adoption Guidelines
  • Althon have a range of Severn Trent specification precast headwalls
  • We have precast headwalls designed to Environment Agency guidelines
  • Althon headwalls are also Sewers for Scotland compliant