Recommendations for Architects: Getting Drainage Designers Involved Early

Introduction:

If you're an architect or developer working on a new site, you've likely encountered the National SuDS Standards and their emphasis on sustainable drainage.

But there's one principle that often gets overlooked in the rush to finalise layouts and submit planning applications: Principle 5, which states that surface water management should inform your site layout from the very beginning.

In reality, drainage designers are frequently brought in after buildings, roads, and plot boundaries have already been fixed.

This creates a disconnect between best practice and what actually happens on the ground. The result? Missed opportunities for cost savings, environmental benefits, and smarter site design.

In this article, we'll explain what Principle 5 really means, why early involvement of drainage expertise matters, and how architects can integrate drainage considerations into the design process from day one. It's not just about compliance; it's about creating better developments.

What Principle 5 Actually Says:

The National SuDS Standards, Principle 5, makes it clear that surface water management should inform the site layout from the very beginning, not be squeezed in afterwards. The idea is that drainage requirements should shape where buildings go, how roads are positioned, and where green spaces sit.

The principle emphasises that early planning allows you to:

• Maximise SuDS opportunities across the entire site, ensuring every area benefits from sustainable drainage

• Integrate water quality treatment by positioning features that cleanse runoff before it reaches watercourses or the wider environment

• Work with existing features like ditches, streams, or natural drainage patterns already on or near the site

• Create multifunctional spaces where drainage solutions double as landscaping, play areas, streets, or rainwater harvesting systems, delivering biodiversity, amenity value, and cost savings all at once

In short, Principle 5 envisions drainage as a design driver, not an afterthought.

The Reality We Face:

In practice, we're typically brought in after the architect and structural engineer have already fixed the building positions and site layout. The drawings arrive with buildings, roads, and plot boundaries set in stone, and our job becomes fitting a compliant drainage system into whatever space is left over.

This creates several challenges:

• Limited SuDS placement options because the best locations are already occupied by buildings or hardstanding

• Missed opportunities for multifunctional design. We can't suggest a swale where a road has already been drawn, or a rain garden where a car park now sits

• Retrofitting rather than integrating, which can increase costs, reduce effectiveness, and limit the environmental and amenity benefits that SuDS should deliver

• Reactive problem-solving instead of proactive, site-wide water management planning

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We work hard to deliver compliant, effective drainage solutions within these constraints, but the truth is that early involvement of the drainage designer would unlock far better outcomes, both for the client and for the environment. When drainage informs layout from day one, you get smarter, more cost-effective, and more sustainable developments.

Recommendations for Architects: Getting Drainage Designers Involved Early

If you're an architect planning a new development, here's how to bring drainage expertise in at the right stage:

1. Include drainage consultants in your initial site appraisal

Before you fix building positions or road layouts, have a brief consultation with a drainage designer. A quick review of site topography, existing watercourses, soil conditions, and local authority requirements can highlight constraints and opportunities that will shape your layout decisions.

2. Schedule a drainage feasibility meeting during concept design

Invite the drainage designer to your early design meetings. Even a single session at the concept stage can identify where SuDS features could sit, how surface water will flow across the site, and whether your proposed layout will create drainage headaches later.

3. Share topographical surveys and site investigation data early

The sooner your drainage designer sees ground levels, soil permeability, and existing drainage infrastructure, the sooner they can advise on realistic options. This avoids costly redesigns when drainage proves unworkable with the fixed layout.

4. Build drainage considerations into your design brief

Make surface water management an explicit part of your project brief from day one. Ask questions like: Where can we integrate SuDS? How can drainage features enhance landscaping or amenity space? What multifunctional opportunities exist?

5. Coordinate with structural engineers and drainage designers together

Structural and drainage requirements often overlap (foundation depths, floor levels, site grading). Bringing both consultants into the same early conversations prevents conflicts and ensures the site layout works for everyone.

6. Budget for early-stage drainage input

A small investment in drainage advice during feasibility or concept design can save significant costs later by avoiding abortive work, redesigns, or compromised solutions. It's far cheaper to adjust a layout on paper than to retrofit drainage into a fixed design.

7. Treat drainage as part of the design team, not a compliance task

When drainage designers are seen as collaborators rather than box-tickers, the whole project benefits. You'll get better integration of SuDS, more creative use of space, and smoother approvals from local authorities and water companies.

By involving drainage designers early, architects can deliver developments that are not only compliant but also more sustainable, cost-effective, and attractive. It's a win for the client, the environment, and the design team.