What is the recommended size of a service pipe for a 2 storey residential house approved by MWSS?

The recommended size of a service pipe for a two-storey residential house, as approved by the Metropolitan Waterworks and Sewerage System (MWSS), is typically ¾ inch (19 mm). This size is adequate to provide enough water flow for the average household needs, including kitchen use, bathroom fixtures, and additional appliances, while maintaining appropriate pressure throughout the system.

A pipe of this size strikes a balance between being large enough to handle peak usage without causing significant pressure loss and being small enough to ensure efficient water distribution. In many residential building codes, ¾ inch pipes are commonly used for service lines because they can meet the demands of a standard home, especially considering the multi-storey nature of the building.

Pipes that are smaller, such as ½ inch (12 mm), may not provide sufficient flow rate for a two-storey home, particularly if multiple fixtures are in use simultaneously. On the other hand, larger pipes like 1 inch (25 mm) or 1 ¼ inch (31 mm) could lead to unnecessary expenses and complexity without offering significant benefits for a typical residential application. Therefore, the choice of ¾ inch represents an optimal compromise between capacity and cost-effectiveness in residential plumbing design.