Knowledge Centre

We all know that Sustainable Drainage Systems (SuDS) have become a cornerstone of modern urban planning, addressing the challenges of managing surface water in a sustainable and environmentally conscious manner.  However, are you aware of the innovations in SuDS technology ? As climate change continues to intensify rainfall events and urbanisation increases impermeable surfaces, innovations…

As drainage design experts, there’s one question we’re asked frequently: “Why do we need a topographical survey for every project?” Here’s why it’s non-negotiable 👇 1. Gravity is Your Best Friend • Drainage systems rely on gravity for efficient water flow • Accurate ground levels ensure proper pipe gradients • Prevents costly design modifications during…

When managing water flow in drainage and sewer systems, selecting the right flow control device is critical. Two commonly used options are orifice plates and vortex flow controllers. Both serve to regulate flow rates, but they operate in fundamentally different ways, each with unique advantages and disadvantages. Orifice Plate An orifice plate is a flat plate with a fixed-size hole…

Picture this: a housing development where children play beside wildflower meadows that quietly manage storm water, where residents enjoy morning coffee overlooking ponds teeming with wildlife, and where every rainfall creates a symphony of natural water management. This isn’t a utopian dream but the reality of developments that successfully integrate Biodiversity Net Gain requirements with…

In an time where water conservation is becoming increasingly critical, grey water recycling presents a sustainable solution to address water scarcity.  Grey water, which is wastewater from non-toilet fixtures such as sinks, showers, and washing machines, can be treated and reused for various non-potable purposes. This practice not only conserves freshwater but also offers numerous…

Before any drainage design work can begin, there’s a crucial set of information and documents needed to ensure your project’s success. Let’s break down these requirements into clear, manageable sections. Essential Documents You Need First, let’s cover the fundamental documents required for any drainage design project: A topographical survey is your starting point – this…

Climate change is no longer a distant threat. It’s a present reality that’s fundamentally changing how we design drainage systems. As drainage designers, we have a responsibility to ensure that the infrastructure we create today can cope with the more extreme weather patterns of tomorrow. That’s where climate change allowances come in. What Are Climate…

The drainage design landscape has undergone a significant transformation with the publication of the National Standards for Sustainable Drainage Systems (SuDS) on 19 June 2025. These new standards, which apply across England, represent a fundamental shift in how we approach surface water management, with rainwater harvesting now positioned as the top priority in the drainage hierarchy. The New Drainage Hierarchy:…

When a flow control device is added at the end of a drainage run, it regulates the rate at which water is discharged from the system. This is crucial for managing surface water runoff and preventing downstream flooding. However, if not managed properly, this can lead to unintended consequences, such as upstream flooding. How Flow…

In today’s rapidly evolving urban landscape, managing surface water while protecting our environment has never been more crucial. At The Drainage Designers, we’ve been at the forefront of this evolution for over four decades. Here’s how we tackled a complex urban development project in Greater London: The Urban Development Challenge – 2.5-hectare brownfield site –…

The convergence of Biodiversity Net Gain (BNG) requirements and Sustainable Drainage Systems (SuDS) represents a transformative opportunity for developers and designers to create developments that deliver multiple environmental benefits.  With the National SuDS Standards now in place and mandatory BNG requirements active since February 2024, understanding how these two frameworks complement each other is crucial…

Introduction When planning a new development or renovating an existing property, the choice of paving materials can significantly impact both drainage performance and long-term costs. As sustainable drainage systems (SuDS) become increasingly important in meeting planning requirements across the UK, permeable paving has emerged as a popular alternative to traditional impermeable surfaces. This article provides…

Ensuring high-quality drainage design is essential in modern infrastructure projects. Causeway Flow, a powerful hydraulic modelling software, provides a robust platform for enforcing best practice design rules. By leveraging its features, we can maintain consistency, accuracy, and efficiency across projects. At The Drainage Designers we use Causeway Flow to ensure that we maintain best practice.…

Property managers across the UK are increasingly responsible for maintaining Sustainable Drainage Systems (SuDS) as these eco-friendly solutions become standard in new developments. However, many struggle with creating effective maintenance schedules that ensure long-term performance whilst managing costs and compliance requirements. Understanding Your SuDS Maintenance Obligations As a property manager, your SuDS maintenance responsibilities extend…

Attenuation storage tanks play a crucial role in managing stormwater runoff, particularly in urban areas where impermeable surfaces can lead to flooding. The size of these tanks is determined by several factors, including the discharge rate agreed with the local authority or water authority.  This article will explain how the size of attenuation storage tanks…

The world of drainage design is evolving rapidly, driven by technological innovation, environmental concerns and changing urban landscapes. As we move further into the 21st century, the future of drainage is being shaped by trends that promise to improve efficiency, sustainability and resilience. Here are some key developments to watch. Smart Drainage Systems The integration…

With over 40 years of experience in drainage design and a proven track record of successful projects across the UK, we’re here to dispel common myths that could impact your project’s success. Our expertise in obtaining planning permissions and working with local authorities puts us in a unique position to provide accurate, professional insights. Myth…

Attenuation is a crucial component in modern drainage design, essential for controlling stormwater and preventing flooding and environmental damage. As urbanisation and climate change increase stormwater runoff, well-designed attenuation systems help manage water effectively and sustainably. Attenuation is a crucial component in modern drainage design, essential for controlling stormwater and preventing flooding and environmental damage.…

Why understanding drainage early in your design process can save thousands and prevent project delays. As architects, you’re trained to think about form, function, and aesthetics – but how often do you consider drainage implications during your initial design phases? After working with architects across England and Scotland over the past 40 years, I’ve seen…

Permeable paving is becoming a vital component of sustainable drainage solutions, helping to manage surface water runoff while promoting groundwater recharge. As urbanisation continues to replace natural surfaces with impermeable materials, the role of permeable paving in drainage design has grown in significance. What is Permeable Paving? Permeable paving refers to a range of paving…

Sustainable Drainage Systems (SuDS) have become non-negotiable for property developers across England and Scotland. With planning authorities increasingly scrutinising drainage proposals and climate change intensifying flood risks, understanding the seven National SuDS Standards isn’t just about compliance. It’s about protecting your investment and delivering developments that stand the test of time. After four decades in…

If you’re planning a development in England or Scotland, you’ve likely encountered the requirement for infiltration testing. But what does that mysterious threshold of 1×10⁻⁶ metres per second actually mean, and why is it so critical to your drainage design? Let’s cut through the technical jargon and explain what you really need to know. Why…

Sustainable Drainage Systems (SuDS) have evolved far beyond simple water management infrastructure. Today’s most successful schemes demonstrate that drainage solutions can simultaneously control surface water, create valuable habitats for wildlife, and provide attractive amenity spaces for communities. This multifunctional approach represents the future of drainage design, delivering multiple benefits from a single intervention. The Triple…

Understanding when you can discharge surface water to a combined sewer is one of the most common questions we encounter in drainage design. The answer isn’t always straightforward, but it’s crucial to get it right to ensure your development meets planning requirements and environmental standards. Understanding Combined Sewers A combined sewer system carries both foul…

Sustainable drainage systems (SuDS) have transformed from a nice-to-have feature into an essential component of modern property development. For developers navigating today’s planning landscape, understanding SuDS isn’t just about ticking boxes. It’s about creating developments that work with nature, meet regulatory requirements, and deliver long-term value. Why SuDS Matters More Than Ever The UK has…

If you’re preparing a planning application for a new development, you’ve likely encountered the term SuDS. But understanding why a Sustainable Drainage System strategy is essential can mean the difference between smooth approval and costly delays. What Is a SuDS Strategy? A SuDS (Sustainable Drainage Systems) strategy is a comprehensive plan that demonstrates how your…

Surface water management has become increasingly critical in modern development projects. With climate change bringing more intense rainfall events and urbanisation reducing natural drainage, developers and designers are seeking innovative solutions that go beyond traditional pipe and tank systems. Green roofs offer a compelling answer, combining effective water management with environmental benefits and aesthetic appeal.…

When it comes to sustainable drainage systems, not every site presents a straightforward solution. Whilst basic SuDS features like permeable paving and simple swales work brilliantly on standard developments, challenging sites demand a more sophisticated approach. After four decades in drainage design, I’ve encountered every conceivable site constraint, and I can tell you that advanced…

We should be aware now that soakaways are often the go-to solution for surface water drainage, but they have one critical weakness: they simply don’t work in clay soils. If you’re a homeowner, architect, or developer facing this challenge, you’re not alone. Clay’s low permeability means water has nowhere to go, leaving you with a…

As the UK faces a projected water deficit of 5 billion litres per day by 2050, property developers are increasingly looking at rainwater harvesting systems not just as an environmental consideration, but as a strategic business decision. The question is no longer whether to implement water reuse solutions, but rather how quickly you can integrate…

With water bills rising across the UK and environmental concerns at the forefront of homeowners’ minds, rainwater harvesting has emerged as a practical solution that delivers both financial savings and sustainability benefits. If you’re looking to reduce your water costs whilst contributing to water conservation, this guide will show you exactly how rainwater harvesting can…

As a housing developer, you’re constantly balancing construction costs, planning requirements, and market appeal. Greywater recycling systems might seem like an additional expense, but they offer strategic advantages that can significantly impact your project’s viability, profitability, and marketability. Beyond the obvious water conservation benefits, greywater systems can reduce infrastructure costs, strengthen planning applications, and create…

Active attenuation represents a different approach to managing surface water on development sites. Unlike passive systems that rely solely on storage volume, active systems use mechanical controls to regulate discharge rates. What Is Active Attenuation? Active attenuation systems incorporate flow control devices, typically vortex valves or electronically controlled outlets, to manage the rate at which…

Greywater recycling systems are increasingly being considered for UK buildings as part of water management strategies. Understanding what these systems can and cannot do helps architects, developers, and building owners make informed decisions. What Is Greywater? Greywater is wastewater from baths, showers, hand basins, and washing machines. It excludes water from toilets (blackwater) and kitchen…

Rainwater harvesting is increasingly being considered in UK building projects as part of a sustainable water management strategy. For architects, understanding the fundamentals of rainwater harvesting can help with meeting planning requirements, achieving water efficiency targets, and supporting broader sustainability goals. What Is Rainwater Harvesting? Rainwater harvesting involves collecting rainwater from roofs or other hard…

When it comes to effective drainage design, two of the most common solutions for managing excess water are upsizing pipes or adding attenuation. Both approaches aim to prevent flooding, comply with local regulations, and ensure long-term performance, but they come with different costs and benefits. So, which option is more cost-effective for your project? Understanding…

Sustainable Drainage Systems (SuDS) are now essential for securing planning permission throughout the UK. While standard SuDS approaches work well for many developments, some sites bring unique challenges such as limited space, difficult ground conditions, or strict environmental requirements. In these situations, moving beyond the basics is crucial. Here is a deeper look at advanced…

Climate change is now a central concern for the UK drainage sector. In 2025, new climate change allowances are fundamentally changing the way drainage systems are designed, approved, and maintained across the country. These changes reflect updated government guidance and an urgent need to future-proof infrastructure against increasingly frequent extreme weather events and unpredictable rainfall…

Sustainable Drainage Systems (SuDS) are now a central part of planning and development in the UK. The National SuDS Standards set out clear requirements for managing surface water in new developments, ensuring both environmental protection and regulatory compliance. This article explains the general requirements set out in paragraphs 2.3 to 2.7, highlighting what architects, developers,…

Permeable pavements are increasingly used in sustainable drainage systems (SuDS) to manage rainwater, reduce surface runoff, and meet planning and environmental regulations. Knowing when a permeable pavement design is compliant is essential for successful project delivery. Here is a detailed explanation of the main compliance rules, including practical scenarios and design tips. Permeable Surfaces Without…

For architects and housing developers, understanding Standard Four of the National SuDS Standards is essential for delivering compliant, sustainable, and marketable projects. This standard is all about water quality and ensuring that runoff from your developments is treated effectively before leaving the site. Why Water Treatment Matters for Your Projects Modern developments face increasing scrutiny…

When it comes to sustainable drainage systems (SuDS), many sites present unique challenges that demand more than standard solutions. While the basics such as permeable paving, soakaways, and swales are essential for managing runoff and improving water quality, complex sites often require a more advanced approach. Here, we explore some cutting-edge SuDS features that can…

Maintenance is no longer the “nice to have” part of drainage and SuDS design. Under newer expectations and standards, long term performance is treated as a core design outcome, not an afterthought. If you are an architect, developer, or homeowner planning a project, the message is simple: if you cannot show how the system will…

If the past couple of weeks have shown anything, it is that the South of England can swing quickly from worrying about surface water and flooding to worrying about water shortages. In Kent and Sussex alone, a major incident was declared as tens of thousands of properties were left without a proper water supply for…

Green roofs, sometimes called living roofs, are more than a nice architectural feature. Done properly, they can become a practical part of your surface water strategy. They help slow down runoff, reduce pressure on drains, and support planning approval where SuDS is expected. This article explains what green roofs do, where they fit in a…

We know that architects and housing developers are under pressure to deliver sites that work on paper and on the ground. Planning conditions are tighter, rainfall patterns are less predictable, and space is always at a premium.  A systems approach to SuDS avoids that. Instead of relying on one feature to do everything, you combine…

f you are an architect or housing developer, you do not need another policy document to read. You need to know what the National SuDS Standards mean in practice, what planners will ask for, and how to avoid the slow, expensive back and forth that can derail a programme. In simple terms, the National SuDS…

Most delays are not caused by complex hydraulics. They are caused by uncertainty. The planner or drainage officer cannot clearly see that the design is appropriate for the site, so they ask questions. Each question creates another round of drawings, notes, and approvals. The most common root cause is a drainage strategy that does not…

The National SuDS Standards promote a clear order of preference for where surface water should go. This is often called the runoff destination hierarchy. It matters because it forces the design team to consider better outcomes first, rather than defaulting to the easiest connection. Option one is to use the water on site, for example…

Infiltration is often treated as the default answer, but it is only a good answer when the ground conditions support it. When it is forced onto a site without evidence, it becomes a planning risk and a construction risk. Infiltration works well when soils can accept water at a reliable rate, groundwater levels are suitable,…