Rain and stormwater systems move water away from roofs, paving and hardstanding areas to prevent pooling and water damage. Unlike a pressurised water supply line, these systems are almost always gravity-fed, which changes what you should look for in fittings.
Why gravity systems use lighter-class pipe
Because stormwater is not being forced through the pipe under pressure, a Class 6 fitting -- with a thinner wall than Class 9 or 16 -- is generally sufficient and more cost-effective for this application. See our Class 6 rain and stormwater fittings.
Getting the fall right
Gravity drainage depends on a consistent downward slope (fall) along the entire run so water keeps moving toward the outlet rather than pooling. When planning a layout, map out bends and junctions so the fall is maintained through every fitting, not just the straight pipe sections.
Plan for maintenance access
Leaves, silt and debris are a fact of life in stormwater systems. Including rodding eyes at reasonable intervals -- particularly at direction changes -- makes it far easier to clear a blockage later without digging up the line. It is a small addition during installation that saves significant effort down the line.
Reducing junctions for multiple roof areas
If you are combining downpipes from several roof areas into one main drain line, reducing junctions let a smaller branch feed cleanly into a larger main pipe without an awkward step in diameter.
Bends for routing around structures
Use 45° or 22.5° bends in pairs to route gently around foundations, paving or other obstacles rather than relying on a single sharp 90° bend wherever possible -- gentler bends keep water flowing smoothly and reduce the chance of silt building up at the turn.
Planning a drainage layout and not sure what you need? Get in touch or send us your site sketch on WhatsApp and we will help you work out a fitting list.