Three parts of Hertfordshire have, or are getting, an HMO Article 4 Direction as of 27 October 2026: Hatfield, where one has been in force since 2011; Potters Bar, where Hertsmere's direction takes effect on 6 May 2027; and Three Rivers, where the district council agreed in June 2026 to prepare a district-wide direction. Everywhere else in the county, converting a house into a small HMO for up to six people remains permitted development, though a licence may still be needed. This page tracks each district, with the source for every date.
Hertfordshire HMO Article 4 Directions by district
In force
- Hatfield (Welwyn Hatfield Borough Council)Confirmed April 2011Covers the whole of Hatfield. Planning permission is needed to convert a home into an HMO; applications are assessed against the council's HMO Supplementary Planning Document.
Made, not yet in force
- Potters Bar (Hertsmere Borough Council)In force 6 May 2027Covers the four wards of Potters Bar. Sealed on 12 August 2026 after a consultation in April to June 2026. From 6 May 2027 a C3 to C4 conversion there needs planning permission.
Proposed
- Three Rivers District Council (whole district)Agreed 2 June 2026Councillors unanimously agreed to prepare a district-wide direction covering HMOs of up to six occupants. It must be consulted on and would take effect about 12 months after being made.
No HMO direction found
- St Albans, North Herts, Watford, Stevenage, Dacorum, Broxbourne, East HertsSt Albans and North Herts have published Article 4 Directions, but for employment areas and town centres, not HMOs. For the others we found no published HMO direction at the date above. Check the national map for the current position.
Sources: Welwyn Hatfield's Article 4 Directions page, Hertsmere's announcement of 26 August 2026, and Three Rivers' announcement of 2 June 2026. Any address can be checked on the national Article 4 Direction map.
What changes when a direction takes effect
| Before the in-force date | After the in-force date | |
|---|---|---|
| Convert a house to a 3 to 6 person HMO | Permitted development, no application | Full planning application, judged against local HMO policy |
| HMO for 7 or more people | Planning permission always needed | No change |
| Existing lawful HMOs | Lawful | Still lawful; the direction is not retrospective |
| HMO licensing | Separate, unchanged | Separate, unchanged |
| Evidence of lawful use | Optional | Worth obtaining a lawful development certificate before the date |
If you are converting before a direction takes effect
- 1
Complete the conversion and start the use before the in-force date
The right is lost on the date, not on the day the direction is made. A conversion in Potters Bar that is let as a C4 HMO before 6 May 2027 keeps its lawful status.
- 2
Apply for a certificate of lawful existing use
It is the evidence you will need when the council, a buyer or a lender asks whether the HMO predates the direction. Keep tenancy agreements and council tax records too.
- 3
Sort the licence separately
If five or more people will share, the mandatory HMO licence is needed from the first day of the tenancy, whatever the planning position.
If you are converting after a direction takes effect
You need a planning application, and the deciding factors are the ones each council sets out in its HMO policy or supplementary planning document: the concentration of HMOs on the street, parking and cycle storage, refuse arrangements, room sizes and the effect on the character of the area. Hertsmere's amenity standards for HMOs and Welwyn Hatfield's HMO SPD are the documents to read before you buy. Our HMO planning permission guide walks through the C3, C4 and sui generis rules and what a successful application looks like.
Running or buying an HMO in Hertfordshire?
Barnab checks the Article 4 position for the address, confirms whether a licence is needed, and prepares the planning or licence application for the right council.
Check my propertyFrequently asked questions
Which parts of Hertfordshire have an HMO Article 4 Direction?
As of 27 October 2026: the whole of Hatfield (Welwyn Hatfield Borough Council, confirmed in April 2011) has one in force. The four wards of Potters Bar (Hertsmere) have one sealed on 12 August 2026 that takes effect on 6 May 2027. Three Rivers District Council agreed on 2 June 2026 to prepare a district-wide direction, which still has to be consulted on. We found no HMO direction published by the other Hertfordshire districts, but check the national Article 4 map for any address before relying on that.
What does an HMO Article 4 Direction actually do?
It removes the permitted development right to change a dwellinghouse (use class C3) into a small HMO for three to six unrelated people (use class C4), so that conversion needs a planning application. It does not affect HMOs that already lawfully exist before the direction takes effect, and it does not change licensing, which is separate.
When does the Potters Bar direction start?
6 May 2027. Hertsmere made it as a non-immediate direction with the statutory 12 months' notice, after a consultation that ran until 17 June 2026. Conversions completed and in use before that date are not caught; conversions after it need planning permission.
Do I still need an HMO licence in an Article 4 area?
Yes, if the property meets the licensing threshold: five or more people from two or more households sharing facilities for mandatory licensing, or whatever the district's additional licensing scheme covers. Planning permission and the licence are two separate approvals from two separate council departments.
