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The Ultimate Guide to Drainage Consultancy For Detailed Drainage Design

In this article, readers will learn about

  • Drainage Consultancy
  • Importance of Proper Drainage Design in the UK
  • Regulations and Compliance for Drainage Design in the UK
  • Steps Involved in Detailed Drainage Design
  • Choosing the Right Drainage Consultant


A drainage system has a vital contribution to the long-term success of an infrastructure. It manages water so it does not lead to flood, pollution, and environmental and infrastructure damage.

Although, it is not easy to create and enforce efficient drainage systems in the UK. There are several unique considerations that arise in terms of the UK’s geographical conditions and government regulations, which require a high degree of skills, expertise, and coordination with different legal authorities. It explains why drainage design projects in the UK require drainage consultancy. Move below for more insights into how this consultancy works and its benefits.

Understanding Drainage Consultancy

Drainage consultancy is a process of evaluating a client’s site condition and infrastructural needs to provide a design for a structure or series of structures that effectively drains away the ground or run-off, whether you want to install a new system or change the existing one. 

They assist you in tailoring a design after understanding local requirements and potential risks and ensuring the safety of the people. Professional guidance is necessary to create a robust system. It’s a long-term investment that saves you from expensive repairs or replacements in the future. You can hire a drainage consultant for

  • Site investigation and feasibility studies
  • Drainage design and modelling
  • Drainage strategy and planning
  • Drainage approval and consent
  • Drainage construction and supervision
  • Drainage maintenance and management

Importance of Proper Drainage Design in the UK

Infrastructure Protection

Significance for Urban Development

Legal Compliance

Environmental Conservation

Resilience to Climate Change

Long Term Cost Savings

Infrastructure Protection

For a small-scale project, a good drainage system safeguards the homes and buildings. On the other hand, large-scale, well-designed systems protect infrastructure like roads, bridges, and buildings by halting the chances of water damage, subsidence, deterioration caused by standing water and many other issues.

Significance for Urban Development

Proper drainage design may facilitate urbanisation. With the rise in population and urbanisation in the UK comes an increase in housing, social amenities, as well as services. Urban development also poses a problem for drainage because it creates more solid surfaces that do not allow the water to seep into the soil. It can lead to runoff, flooding and water pollution in urban areas. 

Drainage Systems that are properly designed will include permeable pavements, green roofs, rain gardens, swales, retention basins, and wetlands, which are all aimed at alleviating such problems. These can reduce runoff volume and peak flows, increasing infiltration and evaporation, filtration of pollutants and sediments, aesthetics, and ecology.

Legal Compliance

Failure to adopt relevant local or state laws during drainage design can lead to legal problems as well as affect the environmental sustainability of any project. The UK has several rules and regulations that cover the design, construction, operation and maintenance of drainage systems, which include the Building Regulations 2010, Water Industry Act 1991, Flood and Water Management Act 2010, NPPF and BS.

These aim to ensure that the drainage systems are safe, efficient, lasting and friendly to the environment. These requirements can be met through proper drainage design based on the best practices and guidelines for drainage planning, assessment, implementation and management.

Environmental Conservation

Following drainage consultancy, effective drainage planning considers ecological impacts, preserving natural habitats and biodiversity while reducing the destruction of ecosystems due to poor water management. It also includes incorporating more sustainable materials and products while installing the system. 

Resilience to Climate Change

It may enhance the resilience to climate change. The UK is predicted to face more droughts, heavy rains and floods resulting from climate change. Such can be daunting on drainage as they determine the availability, distribution, and quality of water resources.

Such challenges may be mitigated through proper drainage design that uses adaptable and responsive approaches that can adapt to changing circumstances and uncertainties. These include rainwater harvesting, reuse, efficiency, flood risk management and emergency planning.

Long-Term Cost Savings

Although implementing comprehensive drainage systems with specialist consultancy may require an initial investment, they often result in long-term cost savings by preventing damage and costly repairs.

Regulations and Compliance for Drainage Design in the UK

For instance, the UK sets laws and standards for drainage design to ensure drainage systems’ safety, efficiency, and sustainability. Some of the key regulations and compliance standards for drainage design are:

The Building Regulations 2010

The regulations stipulate the essential elements for the material, installation, testing, ventilation, approach, maintenance, and protection of the drainage system.

The Water Industry Act 1991

Water Supply (England & Wales), an Act to regulate. The act also defines the duties of water companies, builders, and consumers in respect of drainage systems.

The Flood and Water Management Act 2010

The Floods and Water Management Act in England and Wales forms a basis for managing flood risks and water resources. It also encourages SuDS as a preferred option for surface water management.

The National Planning Policy Framework (NPPF)

This framework outlines the government’s planning policies in England. It promotes integrated drainage into the overall design of development projects to account for issues related to flood hazards, water quality, biodiversity, amenities, and climate change.

The British Standards (BS)

The voluntary standards help set up good practices in drainage design. Some of the relevant BS standards are:

  • BS EN 752: Drain and sewer systems outside buildings
  • BS EN 12056: Gravity drainage systems inside buildings
  • BS EN 16933: Design of stormwater management systems
  • BS 8582: Code of practice for surface water management for development sites

Steps Involved in Detailed Drainage Design

Designing a drainage system in the UK is crucial in ensuring the quality and efficiency of the project. Here are some steps to follow:

Obtain project details

The clients will have to provide development drawings and levels. The drainage consultant will review the design specifications and objectives with the client and the stakeholders. Ensure that the design meets the expectations and needs of the end users and is in accordance with the relevant standards and regulations.

Consult Authorities

The consultant will get approval from the Sewerage Undertaker, Environment Agency and the local authorities about your requirements and also the capacity of your network.

Site Assessment and Data Collection

A detailed field survey needs to be carried out with data collection. It involves gathering information about the site characteristics, such as:

Topography: The shape and elevation of the land surface

Geology: The type and structure of the underlying rocks and soils

Hydrology: The distribution and movement of water on and below the land surface

Ecology: The diversity and interaction of living organisms on the site

Land use: The current and planned activities on the site

Infrastructure: The existing and proposed utilities, roads, buildings, etc. on the site

The site assessment and data collection are made to determine the drainage opportunities and constraints. For example:

  • How much rainfall does the site receive?
  • How does the water flow across the site?
  • How permeable is the soil?
  • How prone is the site to flooding?
  • How sensitive is the site to pollution?
  • How can the site accommodate SuDS features?

Site assessment and data collection can be done using various steps, such as:

Desk study: Reviewing existing maps, reports, records, etc.

Site survey: CCTV surveys, trial holes, topographical surveys, and connectivity surveys.

Site investigation: Soakaway tests to confirm the basic information necessary to complete the drainage design.

Designing Drainage Solutions

A drainage consultant can design the perfect drainage solution for your project. However, the design process is a bit more complex than most people think. They have to consider principles like:

  • Minimising impermeable surfaces
  • Maximising natural infiltration
  • Reducing runoff volume and velocity
  • Controlling runoff quality and quantity
  • Providing adequate storage and conveyance
  • Enhancing Amenities and Biodiversity

In the design of your project, a drainage consultant can incorporate sustainable drainage systems (SuDS). SuDS are used to manage water runoff from sites by mimicking natural processes. Using swales, ponds, rain gardens, permeable paving, and green roofs in your designs, you can get multiple benefits. Some of these include infiltration, attenuation, filtration and amenity. Another thing they look at is how the SuDS scheme can impact the environment, maintenance requirements, and cost-effectiveness.

A drainage consultant can also incorporate a foul drainage system in your design. Foul drainage is the system that collects wastewater from toilets, sinks, showers, etc., so it can be transported to a treatment plant or sewer. The design involves calculating the flow rate, pipe size, slope, and network layout and ensuring compliance with relevant standards and regulations.

A design consultant will use hydraulic models to design your networks and produce detailed construction drawings.

Trends and Innovations in Drainage Design

Incorporating Smart Technology

Use of Hydraulic Modelling

Low-Impact Development (LID)

Incorporating Smart Technology

The use of sensors, data analytics, and real-time monitoring is gaining more popularity. Smart drainage systems are based on advanced technologies and are adapted to changing conditions, improving efficiency and reducing the risk of overflows.

Use of Hydraulic Modelling

Advanced hydraulic modelling tools enable engineers to simulate water flow and analyse the performance of drainage systems more accurately. This helps in optimising system design and identifying potential trouble spots.

Low-Impact Development (LID)

LID principles are gaining prominence as they encourage practices that minimise the impact of urban development on local hydrology. This includes reducing impervious surfaces and promoting infiltration.

Choosing the Right Drainage Consultant

Experience and Expertise


Cost Understanding

Environment-friendly approach

Experience and Expertise

A drainage consultant must have experience designing various projects in the UK. Also, they must have a success rate in those accomplished drainage systems. Their team must have experts of all types, including trained engineers and legal experts. 

Their expertise in handling compliance and design approvals in the United Kingdom is one of the major factors to look for.


Must evaluate if the consultant has specialisation in dealing with complex projects. For instance, if you want a design for a large-scale project like an industrial area or a major residential locality, the consultant must have already worked on such projects. 

Cost Understanding

Compare the costs different consultancy companies offer and understand how everything is priced. Hiring a consultant who offers a fixed price for every project type is advisable to settle on a fair price.

Environment-friendly approach

If your project has environmental considerations, ensure the consultant has experience in sustainable and environmentally responsible drainage practices. It can help meet regulatory and ethical requirements.

Are you looking for a drainage consultancy in the UK?

Urban Water is the leading drainage consultancy in the United Kingdom. We are experts in the design of both an existing property and a new development.

If one needs a drainage strategy for their new project, a foul drainage design for their own house or a SuDS design for a sustainable drainage system, we have this experience. Our services cut across the residential sector, commercial sector, as well as the industrial sector.

Our solutions meet the regulatory and standards requirements, thus assuring safety in all operations. Just like that, we employ state-of-the-art software and technology to ensure our accuracy and speed. Our customer service is based on giving satisfaction. We customise our services based on your needs and within your budget and time frame.

Final Thoughts

Understanding all the aspects associated with effective infiltration systems gives a clear picture of the complexity of the designing process. Without professional drainage consultancy, designing an effective drainage is infeasible. If you need experience, send a quote to Urban Water and be ready for a flawless design consultancy from our experienced engineers.

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Picture of Argemiro Rivera, <b>BEng(Hons) MSC CEng MICE MCIWEM C.WEM CEnv</b>
Argemiro Rivera, BEng(Hons) MSC CEng MICE MCIWEM C.WEM CEnv

Passion for Water, Flood Risk & Sustainability
I love to dig into complex flood risk and water engineering projects and deliver them. I focus on delivering reliable flood risk information to protect livelihoods and the environment.

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