AL postcode district map, St Albans
Supplier statuses last checked .
The AL postcode area covers 10 districts and 7,792 live postcodes, from AL1 to AL10. It is centred on St Albans and also covers Welwyn Garden City, Hatfield and Harpenden.
Districts here average 779 postcodes.
Where the AL districts sit
Where AL sits
The whole area sits inside Hertfordshire, which is unusual at this size.
Water supply across AL
All 10 AL districts are supplied by Affinity Water. That makes AL 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 AL.
The shape of the AL area
AL1 is the largest district with 1,217 postcodes around St Albans, and AL8 the smallest with 422. The area divides into 39 postcode sectors.
District by district: AL1 serves St Albans, AL2 serves St Albans, AL3 serves St Albans, AL4 serves St Albans, AL5 serves Harpenden, AL6 serves Welwyn Garden City, AL7 serves Welwyn Garden City, AL8 serves Welwyn Garden City, AL9 serves Hatfield and AL10 serves Hatfield.
Several districts share a settlement, which is a common source of confusion when a form rejects an address: AL1, AL2, AL3 and AL4 all point at St Albans, AL6, AL7 and AL8 all point at Welwyn Garden City and AL9 and AL10 all point at Hatfield.
What borders AL
AL sits next to WD (Rickmansworth) to the south west, EN (Waltham Cross) to the south east, LU (Luton) to the north west, HA (Bushey) to the south and NW (London) to the south.
Its neighbours run in 4 different directions, so AL is landlocked by other postcode areas on most sides.
AL districts, settlements and water supply
| District | Principal settlement | Water company | Hosepipe ban status |
|---|---|---|---|
| AL1 | St Albans | Affinity Water / Thames Water | Ban in force |
| AL2 | St Albans | Affinity Water / Thames Water | Ban in force |
| AL3 | St Albans | Affinity Water / Thames Water | Ban in force |
| AL4 | St Albans | Affinity Water / Thames Water | Ban in force |
| AL5 | Harpenden | Affinity Water / Thames Water | Ban in force |
| AL6 | Welwyn Garden City | Affinity Water / Thames Water | Ban in force |
| AL7 | Welwyn Garden City | Affinity Water / Thames Water | Ban in force |
| AL8 | Welwyn Garden City | Affinity Water / Thames Water | Ban in force |
| AL9 | Hatfield | Affinity Water / Thames Water | Ban in force |
| AL10 | Hatfield | Affinity Water / Thames Water | Ban in force |
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 AL
No water company covering AL 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 |
|---|---|---|---|---|
| AL1 | Not published by Affinity Water. Check with your supplier. | |||
| AL2 | Not published by Affinity Water. Check with your supplier. | |||
| AL3 | Not published by Affinity Water. Check with your supplier. | |||
| AL4 | Not published by Affinity Water. Check with your supplier. | |||
| AL5 | Not published by Affinity Water. Check with your supplier. | |||
| AL6 | Not published by Affinity Water. Check with your supplier. | |||
| AL7 | Not published by Affinity Water. Check with your supplier. | |||
| AL8 | Not published by Affinity Water. Check with your supplier. | |||
| AL9 | Not published by Affinity Water. Check with your supplier. | |||
| AL10 | 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 AL 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 AL area?
There are 10 AL postcode districts, running from AL1 to AL10, and they contain 7,792 live postcodes across 39 sectors.
What towns does the AL postcode area cover?
AL covers St Albans, Welwyn Garden City, Hatfield and Harpenden. The area takes its name from St Albans, and each district is listed with its settlement in the table on this page.
Which water company supplies AL postcodes?
Affinity Water supplies all 10 AL 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 AL1 and AL2 both say St Albans?
AL1, AL2, AL3 and AL4 all serve St Albans, 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 AL postcode map?
Yes. This page offers the AL 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.
How many postcode sectors are in AL?
AL contains 39 postcode sectors across its 10 districts. A sector is the district plus the first digit of the second half of the postcode, and it is the level a delivery round is actually planned around.
Is there a hosepipe ban in AL?
Yes, across the area: Affinity Water has a restriction in force covering AL. The table on this page shows the position district by district.