What is the maximum permissible height from the top edge of a gully dish to the water level in a gully trap?

The maximum permissible height from the top edge of a gully dish to the water level in a gully trap is specified to be 600 mm. This measurement is crucial for maintaining effective drainage performance and preventing issues such as siphoning, which can compromise the effectiveness of the trap's seal.

A gully trap functions primarily to intercept debris and prevent odors from escaping into the living spaces. The specified distance ensures that there is enough depth of water in the trap to block any potential sewer gases while still allowing waste and water to flow freely through the drainage system. If this height were allowed to exceed 600 mm, the risk of blockages and ineffective sealing due to a lower water level would increase, which could lead to health hazards and unpleasant odors.

In the context of drainage regulations and best practices, adhering to this maximum height helps ensure that the drainage system operates effectively and maintains hygiene standards within the building.