The lead local flood authority as statutory consultee

On a major application, the lead local flood authority consultee response is the one that most often holds a decision. The authority is a statutory consultee on surface water drainage for major development under the Town and Country Planning (Development Management Procedure) (England) Order 2015, and its remit is narrower than most applicants assume. It is not the Environment Agency, it does not police flood zones, and it does not approve your connection to the public sewer.

What it does do is examine how surface water leaves your site, and whether the arrangement will still work in 60 years.

What the consultation requirement covers

Lead local flood authorities were created by the Flood and Water Management Act 2010 and are the county council or the unitary authority for an area. The Development Management Procedure Order then requires the local planning authority to consult them on applications for major development with surface water drainage implications.

Their consultation role is confined to surface water. River and sea flood risk in Flood Zones 2 and 3 is the Environment Agency's area. Connection to a public sewer is a matter for the sewerage undertaker. Groundwater and ordinary watercourse consenting sit with the lead local flood authority in its other statutory capacities, which is why the same team may be dealing with your land drainage consent, but that is separate from the planning consultation.

Which applications trigger it

Major development is the trigger: ten or more dwellings, 1,000 square metres or more of floorspace, or a site of 0.5 hectares or more, measured as the regulations define it. Minor applications do not attract the statutory consultation, though many authorities consult their drainage team informally on smaller schemes in critical drainage areas.

Two traps. A scheme marginally below the threshold on unit numbers can still be major on site area, and applicants sometimes assume they have escaped the consultation when they have not. And a reserved matters or condition discharge submission on a major scheme usually goes back to the drainage team, so the quality of your outline-stage strategy determines how hard the later stages are.

What the authority actually reviews

The review follows the drainage hierarchy and the technical standards. Expect the consultee to work through, in order:

1. Whether discharge to ground by infiltration has been tested and properly ruled out, with soakage test results.
2. Whether discharge to a watercourse has been considered before discharge to a sewer.
3. The discharge rate, benchmarked against the greenfield runoff rate for the site, or betterment where the site is previously developed.
4. Attenuation volume for the design events, including the climate change allowance for peak rainfall intensity.
5. Exceedance routes for events beyond the design standard, shown on a drawing.
6. Water quality treatment, sized by the pollution risk of the contributing surfaces.
7. Maintenance and funding over the lifetime of the development.

Items three and four are where calculations get challenged, and the rainfall dataset used is a frequent point of dispute, as our note on which rainfall dataset to cite in a drainage calculation sets out. Item seven is where responses most often turn into holding objections.

Holding objections and how to clear them

A holding objection is not a refusal recommendation. It means the consultee cannot support the application on the information provided, and it will be withdrawn when the gap is filled.

The gaps that produce them repeat. No infiltration testing, so the hierarchy cannot be assessed. Discharge rates asserted without a greenfield calculation. No climate change allowance stated, or an out-of-date one. No exceedance plan. A maintenance section that names no responsible party. A drainage layout that does not match the site layout, usually because the architect revised the plan and the engineer did not.

Clearing an objection is faster if you ask the consultee what would satisfy them, in writing, and then answer exactly that. Resubmitting a revised strategy with a covering note that lists each point raised and where it is answered saves a second round. A note listing eight points and answering six will come back.

Pre-application engagement with the drainage team

Most lead local flood authorities offer pre-application advice on drainage, often for a fee, and on a major scheme it is money well spent. The questions worth asking before you design are specific.

Is the site in a critical drainage area or an area of known surface water flooding. What discharge rate will the authority expect, and will it accept the greenfield rate calculated by the standard method or require betterment. Which climate change allowance applies for the development's lifetime. Is there a local standard for infiltration testing, treatment or exceedance. And will the authority accept a management company, or does it expect adoption.

Getting those five answers before concept design is the difference between a drainage strategy that is reviewed and one that is redesigned. The same discipline applies to topography-driven schemes, as in our note on managing runoff on a steeply sloping site.

Conditions the authority typically recommends

Three conditions appear in almost every response, and anticipating them is useful because their wording affects your programme.

A detailed surface water drainage scheme to be submitted and approved before development starts, which is a genuine pre-start condition and needs the applicant's written agreement under the statutory procedure. A verification report to be submitted before occupation, confirming the system was built as approved, usually with photographs and as-built drawings. And a maintenance plan with the responsible party named, secured either by condition or by obligation.

Ask for the detailed design condition to be worded so that it can be discharged in phases on a phased scheme. A single condition covering the whole site on a five-phase development will hold up phase one for no good reason.

Where its remit ends

The authority will not tell you whether your site passes the sequential test, whether the flood zone is correct, or whether the Environment Agency will object. It will not negotiate your sewer connection. It will not approve a discharge to a main river, which needs an environmental permit.

It also will not fix a strategy that is the wrong shape for the site. If the ground will not infiltrate, there is no watercourse within reach, and the sewer has no capacity, the drainage answer may be that the site cannot take the proposed density. Finding that out at pre-application stage is uncomfortable. Finding it out at week ten of a thirteen-week determination period is worse.

Put the drainage work in early and keep the drainage strategy and the flood risk assessment consistent with each other, since contradictions between them are a reliable source of consultee queries. To see which flood and drainage documents your site needs, enter the postcode on PlanScope.

PlanScope provides AI-assisted draft reports for planning applications. Reports should be reviewed before submission. We do not guarantee planning approval. For specialist technical reports, qualified professional input may be required.