Planning Advice from the Environment Agency (PDF 355kb)

The Environment Agency provides site-specific pre-application advice
(The benefits of Environment Agency advice (PDF 441kb) and would like to hear from you if your proposed development site is:

  •  is in flood zones 2 or 3 (unless their Flood Risk Standing Advice applies)
  •  contains or is close to a ‘Main River’
  •  is on land affected by contamination
  •  handles waste or hazardous substances (including fuels & oils).

The Environment Agency will highlight any issues in a free written preliminary opinion. The preliminary opinion will highlight the site constraints within their remit; identify any related documents that you will need to submit at the planning application stage; and reference any further assessments, licences or consents that you will require from them. As a minimum they will require a site plan and a brief description of the proposed use.

For sites within Hertsmere please send your enquiry to

Any additional technical advice (including pre-application or post-permission comments) requested outside of the preliminary opinion – such as site visits, meetings or document reviews – will be chargeable at a rate of £100 per hour plus VAT. Further details are available on the GOV.UK website.

The Environment Agency's Role in Development and How They Can Help

Combining their expertise with Natural England and the Forestry Commission, the Environment Agency has produced guidance that explains their roles in new developments.  'Planning: a guide for developers' provides initial information to help you make the most of new development for people and the environment, and how they can help you through the process. They also signpost to more technical advice, including consents and permits you might need.

What's in Your Backyard?

The Environment Agency Data is now available as open data through shared services such as Government Digital Services and MAGIC map. The data offers a range of detailed maps – to show various environmental constraints that may affect your development. Maps include:

  • groundwater aquifers;
  • groundwater Source Protection Zones (SPZs);
  • flood maps;
  • Main Rivers;
  • river quality;
  • historic landfill sites.

Flood Risk Assessment

Flood Risk Assessments will be reviewed for fluvial flood risk by either Hertsmere Borough Council or the Environment Agency. Additionally, the Lead Local Flood Authority will assess surface water flood risk for major developments.

The Environment Agency will review your Flood Risk Assessment for certain sites in Flood Zone 2 and most sites in Flood Zone 3. Some applications, such as the majority of householder extensions, will fall under Environment Agency Flood Risk Standing Advice (FRSA) and may not need a detailed FRA. Where your proposed development is covered by FRSA, you should consult Hertsmere Borough Council directly to discuss their requirements.

Planning permission may not be granted until the FRA has been approved. See the Site-Specific Flood Risk Assessment Checklist and other advice available in the National Planning Practice Guidance.

Revised Climate Change Allowances

The Environment Agency published revised climate change allowances in February 2016. You should refer to ‘Flood risk assessments: climate change allowances’ to determine which allowances should be used to assess future flood risk for your development and location. The revised allowances are based on improved climate science and reflect the catchment characteristics within each river basin district. Applicants must factor the revised climate change allowances into their Flood Risk Assessments rather than the previous 20% for peak river flow. For some development types and locations, it is important to assess a range of risk using more than one allowance. You should contact your local Environment Agency office via for advice on how to incorporate the new allowances into your Flood Risk Assessment.

Flood Risk Activity Permit

Applicants who are proposing to carry out any works within eight metres of the top of bank of a Main River, including demolition, construction or storage, may require a Flood Risk Activity Permit. This was formerly called a Flood Defence Consent. Some activities are also now excluded or exempt. A permit is separate to and in addition to any planning permission granted. Further details and guidance are available on the GOV.UK website:

Applicants may need an environmental permit for flood risk activities if they want to do work:

  • in, under, over or near a main river (including where the river is in a culvert)
  • on or near a flood defence on a main river
  • in the flood plain of a main river
  • on or near a sea defence

It is breaking the law if these activities are carried out without a permit should one be required.

Applicants can use the Flood map for planning to check if their activity is on or near a main river or an ordinary watercourse. Main rivers are highlighted on the map with a dark blue line. Applicants are strongly advised to contact the Environment Agency directly for any proposals close to a main river.

Land Contamination

If your development site is known or suspected to be contaminated (including from previous uses such as industry, fuel storage or agriculture), or the development itself is potentially contaminative, a Preliminary Risk Assessment (PRA) needs to be submitted with your planning application. Environment Agency guidance states that they often need to object to such applications submitted without a PRA, and cannot satisfy this aspect by planning condition.

Groundwater Protection

Groundwater supplies up to 70 per cent of fresh drinking water in this area. The Environment Agency’s Groundwater Protection: Principles and practice’ document outlines the position that they take to ensure that development does not have an impact on groundwater supplies.

Water Efficiency

The south-east region is highly stressed for water resources, with a significant proportion of drinking water supplies from groundwater. The future impacts of population growth and climate change will place additional pressures on these water resources. Developments should be designed to include water efficiency measures, such as low-flow taps and shower heads, dual-flush toilets and water butts in gardens. Ideally, developments should achieve water usage of 110 litres per person per day in line with the Governments Technical Standards for Water efficiency.

Biodiversity and River Restoration

If your development site includes a watercourse or water-dependent habitat, such as wet woodland or floodplain marsh, you must always seek to conserve and enhance these habitats and where possible provide new similar habitats. Watercourses should be left with an appropriately sized, development-free buffer zone on both sides of the channel. Usually, a minimum of eight metres on both sides of the watercourse will be required. Riparian owners should seek to protect and enhance the watercourses on their land and carry out any Water Framework Directive actions in line with the Thames River Basin Management Plan.

You should incorporate green infrastructure as part of your development proposals to provide a network of multi-functional green spaces. These spaces should be capable of delivering a wide range of environmental and quality of life benefits for local communities.