Natural Resources Wales (NRW): flood risk and planning

Natural Resources Wales (NRW) is the Welsh Government-sponsored body that manages flood risk in Wales and advises the planning system on it. It is the Welsh equivalent of the Environment Agency, formed on 1 April 2013 when Environment Agency Wales, the Countryside Council for Wales and the Forestry Commission Wales were merged into a single regulator. For anyone developing land in Wales, NRW is the organisation whose flood maps, technical advice and planning objections can decide whether a site is acceptable.

This guide explains what NRW is, how it manages flood risk, the flood maps it produces, and the part it plays in planning decisions under the revised Technical Advice Note 15 (TAN15), which came into force on 31 March 2025.

The revised TAN15 that took effect on 31 March 2025 was the biggest change to national flood planning policy in Wales in over two decades, replacing both the 2004 TAN15 and the 1998 TAN14.

What is Natural Resources Wales (NRW)?

Natural Resources Wales is Wales's principal environmental regulator, known in Welsh as Cyfoeth Naturiol Cymru. It manages flood risk from main rivers, the sea and reservoirs, regulates the environment, manages the nation's forests, and advises government on the sustainable use of natural resources.

NRW was created in 2013 by bringing three predecessor bodies together, and it now carries out in Wales most of the functions that separate organisations deliver in England. That single-body structure is deliberate: it puts flood defence, environmental permitting, conservation and land management under one roof so that decisions about water, land and development can be taken together rather than in isolation.

Is there an Environment Agency in Wales?

No. The Environment Agency covers England only. In Wales, its flood risk role is carried out by Natural Resources Wales, which took over the functions of the former Environment Agency Wales in 2013. If you are working on a site in Wales, NRW is the body you will deal with on main river and coastal flood risk, not the Environment Agency.

This catches people out regularly, because a good deal of national guidance and mapping is written for England and refers to the Environment Agency throughout. The equivalent Welsh tools, policies and consultation routes sit with NRW, and they are not always identical to their English counterparts. For a comparison of how these responsibilities are split across England, it is worth reading our explainer on who is responsible for managing flood risk.

NRW's role in flood risk management

NRW is responsible for managing flood risk from main rivers, the sea and reservoirs across Wales, and for giving the public and planning authorities the information they need to understand that risk. Its duties sit within the framework set by the Flood and Water Management Act 2010, which established how flood risk authorities in England and Wales work together.

• Flood mapping. NRW produces and maintains the national flood maps that identify land at risk from rivers, the sea and surface water, and that underpin planning decisions.
• Flood warnings. It runs the flood warning service for Wales, issuing alerts and warnings to households and businesses in at-risk areas so they can prepare and respond.
• Flood defences. It builds, operates and maintains flood defence assets on main rivers and the coast, and monitors their condition.
• Catchment-based management. It promotes a whole-catchment approach, including natural flood management measures such as leaky dams, wetland restoration and tree planting to slow water at source.
• Emergency response. It works with local authorities and the emergency services during flood events to reduce disruption and damage.

NRW's flood risk management annual report for 2024 to 2025 records that it responded to around 2,100 planning consultations in the year where a local planning authority had flagged flood risk as a potential constraint.

NRW's flood maps: the Flood Map for Planning and the Flood Risk Assessment Wales map

NRW publishes two different flood maps, and confusing them is one of the most common mistakes on Welsh applications. The Flood Map for Planning is the tool for development; the Flood Risk Assessment Wales map is for public awareness and has no status in planning. Using the wrong one can undermine a submission.

The Flood Map for Planning (FMfP) replaced the older Development Advice Map in December 2021, and the revised TAN15 placed it at the centre of the planning framework and added a "TAN15 Defended Zones" layer showing areas protected to defined design standards. For a full breakdown of how the zones work, see our guide to the Flood Map for Planning Wales and its flood zones. The Flood Risk Assessment Wales (FRAW) map is the public-facing "check your flood risk" service; NRW is explicit that it has no official status for planning. You can view both through NRW's own Flood map for planning service.

NRW and the planning process

NRW is a statutory consultee on flood risk for development in Wales. Where a proposal falls within Flood Zone 2, Flood Zone 3, or a TAN15 Defended Zone of the Flood Map for Planning for rivers or the sea, the local planning authority must consult NRW, and NRW provides technical advice on whether the flood risk can be managed acceptably.

That advice can shape an application in several ways. NRW may confirm that risk is acceptable, recommend mitigation such as raised floor levels or safe access and egress, or object where it considers the risk too high or inadequately assessed. An NRW objection is not an automatic refusal, but it carries considerable weight, and an application that proceeds against one is difficult to defend. NRW also works with local authorities on their Strategic Flood Risk Assessments, which steer where development is allocated in the first place; our explainer on Strategic Flood Risk Assessments covers how those documents feed into local plans.

Where flood risk is a factor, the evidence NRW expects is a Flood Consequences Assessment (FCA) — the Welsh equivalent of an English Flood Risk Assessment, demonstrating that development is safe over its lifetime and does not increase flood risk elsewhere.

NRW publishes its own advice for building in flood risk areas for developers.

How the 2025 TAN15 changed NRW's approach

The policy NRW applies to flood risk in planning is Technical Advice Note 15. The Welsh Government published a substantially revised TAN15 on 31 March 2025, replacing both the 2004 TAN15 and the 1998 TAN14. It reshaped how NRW advises on applications in several concrete ways.

1. It made the Flood Map for Planning the centre of the framework for assessing development.
2. It introduced the Defended Zones concept for areas behind defences meeting 1 in 100 (river) or 1 in 200 (tidal) standards.
3. It widened the range of applications that need a Flood Consequences Assessment.
4. It brought coastal erosion fully into planning policy for the first time.
5. It added a notification direction requiring authorities to notify Welsh Ministers of certain highly vulnerable development on undeveloped land in Flood Zone 3.

Applications registered before 31 March 2025 are assessed against the previous TAN15; anything submitted after that date must use the new version. Because these changes are detailed, we cover them in full in our article on the new TAN15 2025 policy update, alongside a broader explainer of TAN15 and development in Wales. You can also read the Welsh Government's written statement on the publication of TAN15 for the official position.

SuDS in Wales: NRW's role versus the SuDS Approving Body

NRW advises on sustainable surface water management as part of its flood risk role, but it is not the body that approves sustainable drainage systems (SuDS) in Wales. That responsibility sits with local authorities acting as SuDS Approving Bodies (SABs), and Wales took a different path from England here.

On a Welsh scheme, NRW may comment on flood risk while the SAB determines the drainage approval — two separate consents that both need to be satisfied.

Challenges and future outlook

Climate change and continued urbanisation are the two pressures shaping NRW's flood work. Rising sea levels, more intense rainfall and changing storm patterns are expected to increase both the frequency and the severity of flooding in Wales, which is why the revised TAN15 places so much weight on climate allowances and long-term resilience.

NRW's response leans increasingly on nature-based and catchment-scale solutions, such as slowing water at source and restoring floodplains, working alongside traditional engineered defences and better forecasting. For developers, the practical effect is that flood risk is now assessed earlier and over a longer time horizon than it was even a few years ago. Engaging with NRW's requirements early, rather than treating the FCA as a late formality, is the surest way to keep a Welsh application on track.

Frequently asked questions

Get expert help with flood risk and planning in Wales

If you are developing in Wales and need to satisfy Natural Resources Wales on flood risk, Unda's flood risk consultants prepare Flood Consequences Assessments and drainage strategies that meet current TAN15 requirements and stand up to NRW scrutiny. Talk to us about your site through our Flood Consequence Assessment service, and one of our consultants will get back to you.