For years, Sustainable Drainage Systems (SuDS) have been "strongly encouraged" through planning guidance in England without ever being a hard legal requirement. That's changing in 2026. Schedule 3 of the Flood and Water Management Act 2010 is finally being implemented, and it shifts SuDS from a planning nicety into a mandatory part of most new developments — with its own separate approval process.
If you're specifying, ordering, or installing drainage on anything from a housing estate to a commercial yard this year, here's what's actually changing and what it means for the products going in the ground.
What's actually changing
Under the new rules, developers lose the automatic right to connect surface water drainage straight into the public sewer. Instead, sustainable drainage becomes the default expectation for surface water management on new developments, assessed separately from the main planning application.
The other big structural change is the introduction of SuDS Approving Bodies (SABs) within local authorities. These bodies review and approve the drainage strategy independently of planning permission — meaning a development can have planning consent and still not be able to start groundworks until its SuDS strategy is separately signed off. In practice, that means drainage design needs to happen much earlier in the process than many developers are used to, not bolted on once the layout is finalised.
Updated national SuDS standards also raise the bar on what "compliant" actually looks like — pushing beyond box-ticking towards genuine flood risk reduction, water quality improvement, and long-term maintainability.
Why this matters right now
Two things are colliding at once: rising rainfall intensity is putting more pressure on ageing sewer networks, and the volume of new development — homes, solar farms, data centres, logistics sheds — keeps climbing. Local sewer capacity in many areas simply isn't there to keep absorbing surface water runoff the old way. Schedule 3 is the regulatory response to that squeeze, and it applies broadly: even smaller developments and extensions are increasingly expected to demonstrate a sustainable drainage strategy, particularly on sites with any known flood risk.
For contractors and specifiers, the practical takeaway is that drainage strategy now needs sign-off before construction starts, and the SuDS components going into that strategy need to be right first time.
The core SuDS toolkit
A compliant SuDS strategy typically layers several components together, working from where water lands through to where it's ultimately discharged or infiltrated:
Attenuation and infiltration — Soakaway crates remain the backbone of most SuDS schemes, storing runoff from roofs, driveways, car parks and hardstanding and releasing it back into the ground at a controlled rate. They're specifically designed to meet SuDS requirements on developments of any size, from a single driveway extension to commercial-scale attenuation for roads and car parks.
Silt and sediment control — Silt is one of the most common causes of SuDS systems failing prematurely, clogging pipes and reducing a soakaway's storage capacity over time. Silt filter chambers sit upstream of the attenuation system to intercept sediment before it ever reaches the crates, and catchpit chambers provide a similar function further up the drainage run.
Controlled discharge — Where a soakaway alone isn't feasible, or where discharge to sewer or watercourse still requires a controlled rate, vortex flow controls and orifice flow control chambers regulate the release rate, preventing peak flows from overwhelming downstream infrastructure — a specific requirement of most modern SuDS designs.
Land drainage — On greenfield and agricultural sites being brought into development, existing field drainage often needs to be maintained or diverted around the new SuDS strategy. Land drain coils keep these systems functioning through and beyond construction.
Access and maintenance — Every SuDS component needs a maintenance regime to keep performing over its design life. Inspection chambers and manhole covers provide the access points needed to inspect, clear and maintain the network — something SABs are increasingly likely to scrutinise as part of approval, given the new emphasis on long-term system performance.
Getting ahead of it
The developments that move through SAB approval smoothly are the ones where drainage strategy was designed in from the start, not retrofitted once the site layout was fixed. If you're working on a scheme that hasn't yet nailed down its SuDS approach, now is the time — sizing, product selection and maintenance access all get harder (and more expensive) to fix once groundworks are underway.
Our team can help with sizing calculations, product selection and a free drawing take-off for any SuDS scheme, whatever stage you're at. Get in touch or call 0121 351 3230.