Underground Drainage P Trap Gully

Underground Drainage P Trap Gully provides a controlled surface water entry point into an underground drainage system while maintaining an odour barrier. Its integral P-trap creates a standing water seal that blocks foul air from venting back through downpipes, yard drains, or paved areas. The uPVC body delivers long-term durability, chemical resistance, and stable performance under ground loading.

The gully supports foul and surface water drainage layouts, integrates with 110 mm underground pipework, and suits both new installations and replacement work. Two variations are available to suit different outlet directions and site constraints, ensuring flexibility during drainage layout planning.

Universal P Trap Gully - 45° Outlet

Universal 45° P Trap Gully directs the outlet pipe at a shallow angle, making it suitable where the drainage run must be diverted around walls, corners, or existing underground routes.

The 45° outlet supports smoother hydraulic flow than a sharp turn and keeps the system aligned with natural fall direction. It connects directly to 110 mm plain-ended pipe through a push-fit socket and maintains an internal standing water seal to block foul odours.

Its uPVC construction provides long-term resistance to soil chemicals, moisture and ground pressure, making it reliable for downpipes, yard gullies, patios and general surface-water collection where angled connection is needed.

Low Back P Trap Gully - 90° Outlet

Low Back 90° P Trap Gully provides a right-angle discharge designed for locations where the outlet must exit close to a wall or within limited trench space. The low-profile back allows pipework to run directly out of the gully without conflicting with foundations, paving or boundary lines.

Its 90° outlet is commonly used for downpipes positioned tight to walls and for confined service runs where a straight or angled outlet will not fit. The built-in P trap maintains a reliable water seal to prevent odour escape, while the rigid uPVC body withstands long-term burial, ground pressure and chemical exposure in both foul and surface-water systems.

Installation Guide:

• Excavate and prepare a compacted granular bedding layer.

• Position gully level and align outlet with planned pipe direction.

• Insert plain-ended 110 mm pipe into the push-fit socket.

• Fill P-trap with water to activate odour seal before use.

• Surround gully with granular material and complete backfill.

• Keep the top section accessible for inspection and cleaning.

Should you choose a 45° or 90° P Trap Gully?

Choosing between a 45° and a 90° P Trap Gully depends on your pipe layout, space constraints and flow direction. A 45° P Trap Gully is best when the outlet pipe needs to run at an angle, offering a smoother hydraulic transition that supports self-cleansing flow and reduces turbulence in foul or surface-water systems. It is ideal for routing around obstacles, offsets, or areas where the drainage run must follow the natural fall of the ground.

A 90° Low Back P Trap Gully is the right choice when the outlet must exit directly sideways in a tight space. Its compact, low-back body fits close to walls, boundaries, and narrow service corridors where an angled outlet will not align. The 90° outlet provides a direct right-angle discharge while maintaining the required water seal for odour control in underground drainage.

Both designs maintain odour protection through an integral P trap and connect to 110 mm plain-ended pipe via a push-fit socket. The final decision depends on whether your installation needs flow-friendly angled routing (45°) or tight, wall-side positioning (90°) within the drainage layout.