Underground Drainage

What we supply

• 110 mm and 160 mm pipePVC-U underground pipe in 3 m and 6 m lengths.
• Bends, junctions and couplersFittings to change direction and join branches.
• Inspection chambers and coversPlastic chambers with covers rated for the location.
• Gullies and channel drainsTo collect surface water from yards and drives.
• Soakaway cratesFor surface water where ground conditions allow.
• Rainwater systemsGutters, downpipes and fittings.
• Pea gravel beddingBedding and surround for pipe trenches.

Sizes and specifications

Pipe standard	BS EN 1401 (PVC-U underground)
Common sizes	110 mm and 160 mm
Building regulations	Part H (England and Wales) covers drainage

Sizes and standards are typical for the UK market; exact figures depend on the manufacturer and are confirmed on your quote.

Common uses

• New extension drainage
• Rerouting drains
• Yard and drive drainage
• Soakaways

Choosing drainage

Foul or surface water?

Foul (sewage) and surface water often need to go to different places. Check where your drains connect before you order.

Covers for the location

Chamber covers are rated for loads, from pedestrian areas to drives. Tell us where each chamber sits.

Building over or near a sewer

Building near a public sewer may need permission from the water company. Check before you dig.

Building regulations differ across the UK. In England, building work is checked against the Approved Documents, for example Part A for structure and Part L for energy efficiency, through your council's building control team or a registered building control approver. Wales has its own Approved Documents, including its own Part L for energy efficiency, and building control is handled by the local authority or a registered approver. In Scotland most building work needs a building warrant from the local authority, assessed against the Building Standards Technical Handbooks. In Northern Ireland building work follows the Building Regulations (Northern Ireland), with guidance in the Technical Booklets, and applications go to the council's building control team.

How it arrives on site

Pipe travels in 3 m and 6 m lengths; fittings and chambers come boxed or loose with the load. We agree the drop point and offload method when we price your order. Read more about how delivery works.

How much do you need?

A 22 m run of 110 mm drain needs 8 pipes in 3 m lengths (or 4 in 6 m lengths), plus a bend or junction at each change of direction and an inspection chamber where your design shows one. Add pea gravel for bedding and surround and we will price the lot together.

Underground Drainage: questions

What size drainage pipe do I need?

110 mm is the standard size for most domestic underground foul and surface water drains; 160 mm is used for larger runs. Your design or building control will confirm.

What fall should a drain have?

Domestic drains are commonly laid at a gradient around 1:40 to 1:80 depending on the pipe size and flow; follow your approved design or your national drainage guidance (Approved Document H in England and Wales, Technical Handbook section 3 in Scotland, Technical Booklet N in Northern Ireland).

Do I need an inspection chamber?

Drains need access points at changes of direction and junctions in many cases. Your design will show where.

What do I bed drainage pipe in?

Usually pea gravel or a similar granular material around the pipe. We can add it to the order as bulk bags.

Do you supply gutters and downpipes?

Yes, in common profiles and colours, with brackets and fittings.

Can I connect to the public sewer?

New connections to a public sewer usually need approval from the local water company.