Drainage Design Services in Cornwall and the South West

At Flows and Roads Consulting, we provide practical and policy-compliant drainage design services to support planning applications and technical approvals across Cornwall and the South West.

We work with developers, architects and planning consultants to deliver clear, buildable drainage strategies for residential, commercial and mixed-use developments. Whether you require a drainage strategy for outline planning, a detailed SuDS design, or an adoptable Section 104 package, we provide a responsive service with fast turnaround times.

Our designs are developed in accordance with current national and local standards, helping to reduce planning delays and support smooth approval from the Lead Local Flood Authority (LLFA), water companies and local planning authorities.

Highway Drainage located in Mawgan Porth, Cornwall. Drainage Design Services in the Southwest of England

Our drainage design services include:

  • Surface water drainage design

  • Foul water drainage design

  • Sustainable Drainage Systems (SuDS) design

  • Drainage strategies for planning applications

  • Attenuation and flow control design

  • Infiltration drainage and soakaway design

  • BRE365 percolation testing assessments

  • Exceedance flow routing

  • Greenfield runoff rate calculations

  • Section 104 adoptable drainage design

  • Private drainage layouts

  • Technical approval support

Drainage design for planning applications

Drainage is often a key requirement for securing planning permission, particularly on residential developments and sites with challenging levels, flood constraints or limited outfall options.

We prepare robust drainage strategies to support:

  • outline planning applications

  • full planning applications

  • reserved matters submissions

  • discharge of drainage conditions

  • pre-application feasibility studies

Our reports and drawings are prepared to help satisfy local authority and LLFA requirements while remaining practical for construction and future maintenance.

SuDS and attenuation design

Where possible, we prioritise Sustainable Drainage Systems (SuDS) to manage surface water runoff in line with best practice and planning policy.

This may include:

  • permeable paving

  • swales

  • attenuation basins

  • underground storage tanks

  • flow control chambers

  • infiltration systems

Each design is tailored to the site constraints, ground conditions and proposed development layout.

Adoptable and private drainage

We provide both adoptable and private drainage designs, including packages suitable for Section 104 sewer adoption agreements.

Our experience includes foul and surface water systems for housing developments, private commercial sites and mixed-use schemes.

We liaise with water companies, planning authorities and design teams to help move projects efficiently from concept through to approval.

Local drainage design expertise in Cornwall

Based in Cornwall, we support projects across Redruth, Truro, Newquay, Falmouth and the wider South West.

Our local knowledge of authority requirements, planning expectations and site constraints helps us provide efficient, practical drainage solutions that keep projects moving.

For sites with mapped flood constraints, see our Flood Risk Assessment services.

Flood Risk Asessment