On site

Drainage is usually inspected with the trench open: invert levels, gradients, bedding, pipe material, and access (rodding eyes and chambers). An air or water test may follow once the system is connected.

What Building Control will check

Compliance with Approved Document H — falls, materials, ventilation, protection through foundations, and connection to the public sewer or septic tank.

What they do not check

Whether your drainage was a sensible layout, whether your manholes are in inconvenient places for finished landscaping, or whether your falls are generous.