Discharge of Flood Risk and Drainage Conditions: A Complete Guide

Securing planning permission is a major milestone, but for flood-constrained sites the work does not stop there. Planning permissions for development affected by flood risk almost always carry conditions requiring detailed flood risk and drainage information to be submitted and approved before construction can begin, before the development is occupied, or on an ongoing basis throughout its lifetime.

Discharging these conditions efficiently is critical to keeping the construction programme on track. Delays at the condition discharge stage are common — and they are almost always avoidable with proper preparation and an understanding of the process.

This guide focuses specifically on flood risk conditions: those imposed to manage fluvial, tidal, and surface water flood risk, as distinct from the drainage-only conditions covered in our separate guide to discharging drainage conditions. While there is overlap — many permissions carry both flood risk and drainage conditions — the flood risk conditions have distinct requirements and, crucially, different procedural rules around deemed discharge.

Types of Flood Risk and Drainage Conditions

Planning conditions relating to flood risk and drainage fall into three broad categories, each with different trigger points and implications.

Pre-Commencement Conditions

Pre-commencement conditions must be discharged before any development begins on site. These are the most common type of flood risk condition and the most critical from a programme perspective, because construction cannot lawfully start until the LPA has approved the submission.

Typical pre-commencement flood risk conditions require:

• Detailed flood risk mitigation scheme. A comprehensive document setting out the flood risk mitigation measures for the development, including finished floor levels, flood resilience and resistance measures, safe access and egress arrangements, and compensatory flood storage design. This goes beyond the outline mitigation in the flood risk assessment to provide construction-level detail.
• Detailed surface water drainage scheme. A full engineering design for the surface water drainage system, including pipe networks, SuDS features, attenuation storage, flow control devices, and exceedance routing. The design must be supported by hydraulic calculations demonstrating compliance with the approved drainage strategy.
• Flood warning and evacuation plan. For residential development in flood risk areas, the EA often recommends a condition requiring a site-specific flood warning and evacuation plan. This plan must demonstrate that occupants can be warned of an impending flood and evacuated safely.
• Compensatory flood storage details. Where the development encroaches on the floodplain, the detailed design of the compensatory storage — including earthworks plans, sections, volumes, and phasing — must be submitted and approved before construction begins.

Pre-Occupation Conditions

Pre-occupation conditions must be discharged before the development (or a specified phase) is occupied. They allow construction to proceed but prevent occupation until specific matters are resolved.

Common pre-occupation flood risk conditions include:

• Verification that flood mitigation measures have been implemented. A report confirming that finished floor levels, flood barriers, resilient construction, and other mitigation measures have been constructed in accordance with the approved scheme.
• Drainage verification report. Confirmation that the drainage system has been built as designed, including as-built surveys, flow control device testing, and photographic evidence.
• Flood warning and evacuation plan activation. Evidence that the site has been registered with the EA’s flood warning service and that the evacuation plan is operational.
• Management company details. Confirmation that a management company has been established (or an alternative arrangement agreed) to take responsibility for the long-term maintenance of SuDS features and flood mitigation infrastructure.

Ongoing Conditions

Ongoing conditions apply for the lifetime of the development. They typically require:

• Maintenance of SuDS features in accordance with the approved management plan. The drainage system must be maintained throughout the lifetime of the development. Failure to maintain it is a breach of the planning condition.
• Retention of compensatory flood storage. The compensatory storage areas must be retained in perpetuity and must not be built upon, filled, or obstructed.
• Retention of flood flow routes. Any overland flood flow routes identified in the FRA must be kept clear and unobstructed.

The Deemed Discharge Exclusion for Flood Risk Conditions

This is a critical point that many developers and their agents overlook.

Under Article 27 of the Town and Country Planning (Development Management Procedure) (England) Order 2015, if the LPA fails to notify the applicant of its decision on a condition discharge application within the prescribed period, the condition is deemed to be discharged. This “deemed discharge” provision exists to prevent LPAs from unreasonably delaying the discharge process.

However, Article 27A excludes flood risk conditions from deemed discharge. Conditions relating to flood risk and drainage imposed following an Environment Agency objection are among the categories of condition that cannot be deemed discharged by the passage of time. This means that if the LPA does not respond to your discharge application, the condition remains undischarged — you cannot simply proceed as if it has been approved.

The practical implication is significant. For non-flood conditions, the deemed discharge mechanism provides a backstop that limits how long the LPA can delay. For flood risk conditions, there is no such backstop. If the LPA (or the EA, as consultee) is slow to respond, you have no automatic remedy. This makes it all the more important to submit comprehensive, well-prepared discharge applications that minimise the risk of delay.

What Each Submission Must Include

The content of a condition discharge submission depends on the specific wording of the condition, but a robust submission for flood risk and drainage conditions typically includes the following.

For Flood Risk Mitigation Conditions

• Finished floor levels survey or design drawings confirming that floor levels are set at or above the required level (typically the 1% annual probability flood level plus climate change allowance plus a freeboard of 300mm to 600mm, as specified in the approved FRA)
• Flood resilience and resistance measures specification — details of flood-resistant construction (waterproof membranes, raised electrical fittings, non-return valves on drainage connections) if required by the condition
• Safe access and egress plan — a plan and supporting assessment demonstrating that a safe route to and from the development is available during the design flood event
• Compensatory storage earthworks plan — detailed design drawings, cross-sections, cut-and-fill calculations, and phasing plan for compensatory flood storage

For Drainage Conditions

• Detailed drainage layout with pipe sizes, gradients, invert levels, and manhole schedules
• Hydraulic calculations (MicroDrainage, InfoDrainage, or equivalent) for the full range of storm events up to the 1 in 100 year plus climate change design storm
• SuDS feature construction details — cross-sections and specifications for permeable paving, swales, basins, ponds, and other features
• Flow control device details — specifications for hydrobrakes, orifice plates, or vortex flow controls
• Exceedance routing plan with spot levels demonstrating that exceedance flows are directed to areas of low consequence
• Maintenance and management plan — see below
• Management company details — the name, contact details, and constitutional arrangements for the body responsible for long-term maintenance

The Maintenance and Management Plan

The maintenance plan is a critical component that is frequently underprepared. The plan should include:

• A schedule of all SuDS features and drainage infrastructure requiring maintenance
• Maintenance tasks for each feature (e.g., sediment removal from swales, jet-washing of permeable paving, inspection of flow control devices)
• Maintenance frequencies (typically annual minimum, with more frequent inspections in the first year after construction)
• Estimated annual maintenance costs
• The responsible party and the legal mechanism securing maintenance in perpetuity (management company articles of association, Section 106 agreement, or adoption agreement)
• Procedures for remedial action if inspections reveal deficiencies

Fee Structure

Condition discharge applications in England are subject to a fee, currently set at:

• £145 per request for standard applications (where each “request” covers the discharge of one or more conditions on a single planning permission)
• £462 for householder applications (a change introduced in recent fee schedule amendments that increased the householder fee above the standard rate)

Note that a single fee covers the discharge of multiple conditions on the same permission, provided they are submitted together. It is therefore cost-effective to group all flood risk and drainage condition discharge applications into a single submission where possible.

There is no fee for resubmission following a request for additional information, provided the resubmission relates to the same condition discharge application.

LPA Review Timeline

The prescribed period for the LPA to determine a condition discharge application is 8 weeks from the date of receipt. In practice, the timeline is often longer:

• The LPA will consult the EA and/or LLFA, each of which has its own response period (typically 21 days statutory, often longer in practice)
• If the consultee requests additional information or amendments, the clock effectively resets
• Complex submissions involving hydraulic modelling review can take 10 to 12 weeks
• LPAs with heavy caseloads may exceed the 8-week target

A realistic expectation for straightforward condition discharge is 8 to 12 weeks. For complex flood risk conditions requiring EA review of modelling or compensatory storage design, allow 12 to 16 weeks or more.

Remember: the deemed discharge exclusion means there is no automatic fallback if the LPA exceeds these timescales. Proactive management of the application — regular contact with the case officer, prompt responses to queries, and early engagement with the EA and LLFA — is essential.

What Happens When the EA or LLFA Objects at Discharge Stage

If the EA or LLFA objects to the condition discharge submission, the LPA will not approve the discharge. The objection will typically identify specific deficiencies or concerns that must be addressed before the condition can be discharged.

Common reasons for objection at discharge stage include:

• The detailed design is inconsistent with the flood risk assessment or drainage strategy approved at planning stage
• Finished floor levels are lower than the level specified in the approved FRA
• Compensatory storage volumes are insufficient or do not provide level-for-level compensation
• The drainage calculations use incorrect rainfall data or climate change allowances
• The maintenance plan is inadequate or does not identify a credible responsible party
• BRE 365 infiltration testing has not been carried out (or results do not support the proposed design)
• Exceedance routing has not been demonstrated

The process for resolving the objection is the same as at planning application stage: review the concerns, prepare revised evidence, and resubmit. Each cycle of consultation adds 4 to 8 weeks.

Common Reasons for Discharge Refusal

Beyond consultee objections, LPAs may refuse condition discharge for several reasons:

• Incomplete submission. The application does not address all the matters specified in the condition. Read the condition wording carefully and ensure every element is covered.
• Non-compliance with the approved FRA or drainage strategy. The detailed design departs from the principles established in the approved documents without justification or LPA agreement.
• Inadequate management arrangements. The maintenance plan does not demonstrate that a credible, funded mechanism is in place for the lifetime of the development.
• Missing consultee response. The LPA may delay determination until the EA or LLFA has responded, even if this exceeds the statutory period.

Tips for Avoiding Condition Discharge Delays

1. Start early. Begin preparing the condition discharge submission as soon as planning permission is granted. Do not wait until the construction programme demands it — by then, any delay is directly on the critical path.
2. Read the conditions carefully. Each condition has specific requirements. A generic submission that does not address the specific wording of the condition will be sent back.
3. Engage the EA and LLFA before submission. If the conditions were imposed following EA or LLFA consultation at planning stage, contact them before submitting the discharge application to understand any specific expectations.
4. Ensure consistency with the approved FRA and drainage strategy. The detailed design must be demonstrably consistent with the principles established at planning stage. If changes are needed, discuss them with the LPA and consultees before submission.
5. Provide a complete submission first time. Incomplete submissions are the single biggest cause of delay. Include all drawings, calculations, reports, and supporting documents in the initial application.
6. Include a condition compliance schedule. A covering letter or table that maps each condition requirement to the specific document and section where it is addressed makes the reviewer’s job easier and reduces the risk of items being overlooked.
7. Commission infiltration testing early. BRE 365 testing takes time to arrange and is season-dependent (winter testing is preferred). Commission it well in advance of the discharge submission.
8. Establish the management company early. Management company details are frequently the last item to be finalised, causing last-minute delays. Set up the management arrangements in parallel with the technical design.

For the full lifecycle of a project from FRA through to condition discharge and verification, see our full project lifecycle case study. For a detailed guide to the drainage strategy process, see our drainage strategy guide.

How Aegaea Can Help

Aegaea handles flood risk and drainage condition discharge submissions from start to finish. We prepare the detailed designs, calculations, mitigation schemes, and maintenance plans required to discharge your conditions — and we manage the consultation process with the EA and LLFA to minimise delay.

Our team understands the specific requirements of different LPAs, EA area teams, and LLFAs across England, Scotland, and Wales. We know what each consultee expects to see, and we prepare submissions that address their requirements comprehensively on the first submission.

Whether you need to discharge a single pre-commencement drainage condition or a full suite of flood risk and drainage conditions across a phased development, we can help. Contact us for a no-obligation discussion about your condition discharge requirements.