Three Rivers Planning Consultant
Chalk valleys, Metro-land and a plan under direction
Three Rivers is one of the most tightly constrained districts in the country. Green Belt covers 77 per cent of it, part of the Chilterns National Landscape reaches into Chorleywood and Sarratt, and a government direction now drives its new Local Plan. Cedar Planning prepares applications, representations and appeals that engage with how Three Rivers District Council actually decides cases.
Cedar is a Chartered practice led by Dan Malloy MRTPI. We work across England, including south west Hertfordshire, and arrange site visits in Rickmansworth, Croxley Green, Abbots Langley and South Oxhey when a project calls for one.
- RTPI Chartered
- Fixed-fee quotations
- Direct advice from a Chartered Planner
An old plan, a housing shortfall and a ministerial direction
Decisions in Three Rivers still rest on the Core Strategy adopted in October 2011 and the Development Management Policies LDD adopted in July 2013. Core policies carry a CP prefix, such as CP1 on sustainable development and CP12 on design, while the detailed tests sit in DM1 onwards. Both documents predate several rewrites of national policy, so officers often weigh them against the current NPPF.
Housing delivery is the pressure point. The council's own April 2026 land supply update puts supply at about 1.19 years against a base date of 1 April 2025, and the 2023 Housing Delivery Test result was 30 per cent. With so short a supply, the presumption in favour of sustainable development is engaged, although Green Belt and National Landscape policy can still justify refusal.
On 18 March 2026 the Housing Minister used powers under the Planning and Compulsory Purchase Act 2004 to direct the council's plan. The draft had met only around 56 per cent of identified need. The direction required roughly 85 per cent, named additional Green Belt sites, and set deadlines of 31 July 2026 for publication and 30 November 2026 for submission.
The resulting Local Plan 2026 to 2042 was published for Regulation 19 consultation from 31 July to 25 September 2026, and the council expects examination in 2027. Sites written in at the minister's request include land at Rousebarn Lane, East Green Street, Oxhey Lane, Little Oxhey Lane and Watford Road, plus the Kings Langley Estate and, conditionally, Batchworth Golf Course.
Landowners: the submission window is short
With submission due by the end of November 2026, the evidence and representations made now will frame the examination. If you control land on the edge of Rickmansworth, Abbots Langley or South Oxhey, our strategic land promotion service can set out how it performs against Green Belt purposes and grey belt tests.
What makes Three Rivers different
Policy DM2 caps a Green Belt replacement dwelling at the size of the original, or 110 square metres excluding garage where the original is smaller. Many rural rebuild schemes turn on that figure.
Policy DM7 protects 546 hectares of the Chilterns National Landscape, mostly chalk stream valleys and wooded hillsides around Chorleywood and Sarratt, including views into and out of the protected area.
Appendix 2 of the DM document sets rear extension depths of 3.6 metres, or 4 metres for detached houses, a 45 degree splay for two storey additions and 1.2 metre flank gaps.
In 2026 the council prepared evidence for a proposed non-immediate, district-wide Article 4 Direction removing the right to convert a house to a small HMO. Check its status before buying for shared letting.
Planning services for Three Rivers projects
Each service is priced as a fixed-fee quotation once we understand the site. These are the areas where clients in the district most often ask for help.
Planning Applications
Full and householder applications in Rickmansworth, Croxley Green and Abbots Langley, with drawings checked against the Appendix 2 design criteria and amenity space standards before submission.
View serviceGreen Belt Extensions
Cumulative floorspace and volume calculations measured from the original dwelling, framed around DM2's proportionality test, for homes in Sarratt, Chorleywood, Bedmond and the rural fringe.
Read the guideLocal Plan Representations
Soundness representations on the directed 2026 to 2042 plan, whether you support an allocation, want a site added or are challenging housing numbers and Green Belt release.
View serviceHeritage Statements
Assessments for listed buildings and the district's 22 conservation areas, including Rickmansworth town centre, Chorleywood Common and Batchworth Heath, proportionate to the significance affected.
View serviceHMO Planning
Advice on shared housing near the Metropolitan line stations while the proposed district-wide Article 4 Direction moves forward, including whether an existing use is already lawful.
View servicePlanning Appeals
Appeals against refusals in the district, using the shortfall in housing land and the weight of out-of-date policies where they help, and dealing squarely with Green Belt harm.
View serviceHow the Three Rivers policy framework fits together
The 2013 Development Management Policies document does most of the work on smaller schemes. DM1 covers residential design and layout and points to Appendix 2, which is unusually prescriptive. It sets private garden space by bedroom count, from 42 square metres for a one bedroom home to 105 square metres for four bedrooms, a 28 metre back to back distance, and a 3 metre private zone next to each dwelling.
Beyond the settlements, DM2 and national Green Belt policy apply. The December 2024 NPPF added grey belt as a route for some previously developed or weakly performing land, and it is already relevant to sites around the edges of South Oxhey, Maple Cross and Abbots Langley. The Colne Valley Regional Park, which follows the river past Rickmansworth and Maple Cross, adds a further landscape and recreation layer in the west of the district.
The Community Infrastructure Levy was adopted on 24 February 2015 and took effect on 1 April 2015. New dwellings and annexes are liable whatever their size, so a garden annexe or a single self-build house needs the relevant exemption forms in place before work starts.
Key policy areas we navigate
Extensions must not be disproportionate, alone or with earlier additions, and curtilage creep into the countryside is resisted.
Proposals that fail to conserve the Chilterns National Landscape or its setting are refused.
The Core Strategy design policy, applied alongside DM1 and Appendix 2 for most residential schemes.
Charged since April 2015, with annual indexation and different rates by use and location.
A Consultancy That Works With You, For You
Three Rivers combines a very weak housing land position with some of the strongest protective designations in the region. That tension is where applications are won or lost. A scheme that leans only on the shortfall will usually fail on Green Belt grounds, while one that ignores it gives away its best argument.
Early advice helps most on replacement dwellings, garden subdivisions and conversions of rural buildings, and for landowners deciding whether to engage with the directed Local Plan before it reaches examination.
RTPI Chartered
Led by a Chartered member of the Royal Town Planning Institute with more than ten years of public and private-sector planning experience.
Honest Prospects
A realistic view of the planning risks and options before you commit time or money.
Fixed, Transparent Fees
Fixed-fee quotations agreed before work starts, so you know the cost from the outset.
Direct Access
You deal with the Chartered Planner doing the work, not an account manager.
Planning Consultants Across Hertfordshire
We cover every council area in Hertfordshire. See our main Hertfordshire planning consultant page.
Three Rivers Planning FAQs
Does the shortfall in housing land mean most schemes in Three Rivers get approved?
No. The shortfall engages the presumption in favour of sustainable development, but national policy lets Green Belt and National Landscape protection override it where harm is clear. Across 77 per cent of the district that still matters. The shortfall carries most weight on sites inside settlements, on previously developed land and on land that qualifies as grey belt.
How far can I extend a house at the back in Rickmansworth or Croxley Green?
Appendix 2 of the Development Management Policies suggests single storey rear extensions of up to 3.6 metres, or 4 metres for a detached house, and a 45 degree splay test for two storey additions. Permitted development may allow more in some cases. See our householder applications page for how we approach it.
Why is the government involved in the Three Rivers Local Plan?
The Housing Minister issued a direction on 18 March 2026 after concluding that the draft plan, which met around 56 per cent of need, was unlikely to be found sound. It required a higher housing figure, named extra sites and set deadlines for publication and submission. The council cannot withdraw the plan.
Will a garden annexe in Chorleywood be charged CIL?
New annexes are liable for the Three Rivers levy regardless of size, but an exemption for residential annexes is available if the right forms are submitted and acknowledged before development starts. Missing that step can lead to a full charge plus surcharges, so it should be handled at the permission stage.
Can I still convert a family house into a small HMO in Three Rivers?
At present the national permitted development right may apply, but the council has prepared evidence for a district-wide, non-immediate Article 4 Direction to remove it. Once confirmed, planning permission will be needed. Anyone buying for shared letting should check the direction's status first.
What should I do if Three Rivers refuses my application?
Read the reasons and the officer report closely. Some refusals are best answered by a revised scheme, others by an appeal. Householder appeals must be lodged within 12 weeks. Our householder appeals page explains how we assess the options.
Get a Free Quote
Tell us what you are trying to achieve and where the property or site is. We will give you an initial view and a fixed-fee quote.
Or email us at info@cedarplanning.co.uk with the relevant information.
Whether you are planning an extension in Chorleywood or promoting land near South Oxhey, book a free 15-minute call or read about our feasibility studies and rural planning work.