Drainage

The system of pipes, gullies, and inspection chambers that carries waste water (foul drainage) and surface water (rainwater) away from a building. Extensions that add kitchens, bathrooms, or WCs require new connections to the foul drainage system. Rainwater from the extension roof must be drained - either to a soakaway or the surface water drain - not to the foul sewer. Changes to drainage serving multiple properties may require building regulations or water authority approval.