WD postcode district map, Rickmansworth
Supplier statuses last checked .
The WD postcode area covers 12 districts and 7,405 live postcodes, from WD3 to WD99. It is centred on Watford and also covers Bushey, Rickmansworth, Borehamwood, Radlett and Hemel Hempstead.
Districts here average 617 postcodes.
Where the WD districts sit
1 district is plotted without a label where labels would overlap; every one is in the table below.
Where WD sits
It falls across Hertfordshire, Buckinghamshire and Greater London.
Water supply across WD
All 12 WD districts are supplied by Affinity Water. That makes WD simple in a way many areas are not: one company, one set of rules, one status to check.
Affinity Water has a hosepipe ban in force from 11 July 2026, covering the whole of WD.
The shape of the WD area
WD3 is the largest district with 1,281 postcodes around Rickmansworth, and WD99 the smallest with 21. The area divides into 53 postcode sectors.
The numbering is not continuous. WD runs up to 99 but has only 12 districts, so 85 numbers are unused:.
District by district: WD3 serves Rickmansworth, WD4 serves Hemel Hempstead, WD5 serves Watford, WD6 serves Borehamwood, WD7 serves Radlett, WD17 serves Watford, WD18 serves Watford, WD19 serves Bushey, WD23 serves Bushey, WD24 serves Watford, WD25 serves Watford and WD99 serves Watford.
Several districts share a settlement, which is a common source of confusion when a form rejects an address: WD5, WD17, WD18, WD24, WD25 and WD99 all point at Watford and WD19 and WD23 all point at Bushey.
What borders WD
WD sits next to HA (Bushey) to the south, AL (St Albans) to the north east, UB (Ashford) to the south, NW (London) to the south east and N (City of London) to the south east.
WD districts, settlements and water supply
| District | Principal settlement | Water company | Hosepipe ban status |
|---|---|---|---|
| WD3 | Rickmansworth | Affinity Water / Thames Water | Ban in force |
| WD4 | Hemel Hempstead | Affinity Water / Thames Water | Ban in force |
| WD5 | Watford | Affinity Water / Thames Water | Ban in force |
| WD6 | Borehamwood | Affinity Water / Thames Water | Ban in force |
| WD7 | Radlett | Affinity Water / Thames Water | Ban in force |
| WD17 | Watford | Affinity Water / Thames Water | Ban in force |
| WD18 | Watford | Affinity Water / Thames Water | Ban in force |
| WD19 | Bushey | Affinity Water / Thames Water | Ban in force |
| WD23 | Bushey | Affinity Water / Thames Water | Ban in force |
| WD24 | Watford | Affinity Water / Thames Water | Ban in force |
| WD25 | Watford | Affinity Water / Thames Water | Ban in force |
| WD99 | Watford | Affinity Water / Thames Water | Depends on your supplier |
Principal settlement is the town or city each district sits in or nearest to, derived from OS Open Names. It is not the Royal Mail post town, which is licensed data and not published openly. Status is resolved live from each company’s own notice.
Water hardness in WD
No water company covering WD publishes hardness figures as open data. The gap is named per district below so you know who to ask.
| District | Hardness | As published | Supply zone | Published by |
|---|---|---|---|---|
| WD3 | Not published by Affinity Water. Check with your supplier. | |||
| WD4 | Not published by Affinity Water. Check with your supplier. | |||
| WD5 | Not published by Affinity Water. Check with your supplier. | |||
| WD6 | Not published by Affinity Water. Check with your supplier. | |||
| WD7 | Not published by Affinity Water. Check with your supplier. | |||
| WD17 | Not published by Affinity Water. Check with your supplier. | |||
| WD18 | Not published by Affinity Water. Check with your supplier. | |||
| WD19 | Not published by Affinity Water. Check with your supplier. | |||
| WD23 | Not published by Affinity Water. Check with your supplier. | |||
| WD24 | Not published by Affinity Water. Check with your supplier. | |||
| WD25 | Not published by Affinity Water. Check with your supplier. | |||
| WD99 | Not published by Affinity Water. Check with your supplier. | |||
Hardness is published per census area, not per postcode, so these figures characterise a district rather than measuring one address. They are a scale and taste matter, not a safety one. Hardness data version wessex-water@2022-2025+yorkshire-water@2026.
Download the WD data
No signup, no email wall. GeoJSON carries the district points, the supplier and the live status, so it can be dropped straight into a map.
District positions are averaged postcode centroids from OS Code-Point Open. They show roughly where a district sits, not where its boundary runs, and are not legal boundaries.
Frequently asked questions
How many postcode districts are in the WD area?
There are 12 WD postcode districts, running from WD3 to WD99, and they contain 7,405 live postcodes across 53 sectors.
What towns does the WD postcode area cover?
WD covers Watford, Bushey, Rickmansworth, Borehamwood, Radlett and Hemel Hempstead. The area takes its name from Watford, and each district is listed with its settlement in the table on this page.
Which water company supplies WD postcodes?
Affinity Water supplies all 12 WD districts. Supply boundaries follow the pipe network rather than postcode geography, so confirm against your water bill if you are near the edge of the area.
Why do WD5 and WD17 both say Watford?
WD5, WD17, WD18, WD24, WD25 and WD99 all serve Watford, covering different parts of it. A single town routinely needs more than one postcode district once it passes a few thousand delivery points, so this is normal rather than an error in an address.
Can I download a free WD postcode map?
Yes. This page offers the WD districts as GeoJSON, CSV and SVG, free and with no signup or email address required. The GeoJSON carries each district's position, its water company and its current restriction status, so it can be dropped straight into a mapping tool.
Which councils cover the WD postcode area?
WD reaches into Hertfordshire, Buckinghamshire and Greater London. A postcode area is not a council area: they were drawn for different purposes and a single district can sit across a council boundary, so your postcode does not tell you which authority you pay.
Why is there no WD16 postcode district?
WD16 is not in use. Postcode districts are allocated as sorting requirements change rather than numbered straight through, and a code that is retired or never brought into service is not reissued, so gaps in the sequence are normal.