Drain Installation

New drainage — for an extension, a garden room with plumbing, a new soil stack, or replacing a system past saving — is groundwork with rules: falls, depths, bedding, access points and materials all specified by Building Regulations Part H.

WaterTrust contractors install foul and surface water drainage that passes inspection first time, from a single new gully to a whole-plot system.

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What the work involves

• Setting out to the designed line, depth and fall (typically 1:40–1:80)
• Excavation, pea-shingle bedding and laying of new pipework
• Inspection chambers and rodding access at changes of direction
• Backfill, testing, and connection to the existing system or sewer

When you need it

• An extension or loft conversion adding bathrooms
• A garden building needing foul drainage
• Replacing pitch fibre or collapsed clay systems
• Separating surface water from a combined system

Drain Installation — common questions

Do I need Building Control?

New drainage work is notifiable — either through your project's Building Control or a competent contractor's process. Your contractor will confirm what your job needs.

What fall does a drain need?

Roughly 1:40 to 1:80 for 100mm foul pipe — enough to carry solids, and not so steep that the water leaves solids behind. It's the detail that separates drains that work for decades from drains that block yearly.

Plastic or clay?

Both are approved; plastic dominates domestic work for speed and joints. Your contractor will match material to loads and ground.

Ready to get quotes?

Post the job free — approved contractors across the UK see it straight away.