MK postcode district map, Bletchley
Supplier statuses last checked .
The MK postcode area covers 28 districts and 16,215 live postcodes, from MK1 to MK77. It is centred on Milton Keynes and also covers Bedford, Kempston, Bletchley, Flitwick and Woburn Sands.
Districts here average 579 postcodes.
Where the MK districts sit
5 districts are plotted without a label where labels would overlap; every one is in the table below.
Where MK sits
It is administratively fragmented, reaching into Milton Keynes, Bedford, Central Bedfordshire and Buckinghamshire and 2 other authorities.
Water supply across MK
All 28 MK districts are supplied by Anglian Water, which is notable at this size: an area with this many districts usually crosses at least one supply boundary, and this one does not.
Anglian Water has a hosepipe ban in force from 11 July 2026, covering the whole of MK.
The shape of the MK area
The districts are wildly uneven: MK45 holds 1,313 postcodes around Flitwick and MK20 holds 6, a ratio of about 219 to one. They divide into 110 sectors.
The numbering is not continuous. MK runs up to 77 but has only 28 districts, so 49 numbers are unused:.
Several districts share a settlement, which is a common source of confusion when a form rejects an address: MK5, MK6, MK8, MK9, MK10, MK11, MK12, MK13, MK14, MK15, MK19 and MK77 all point at Milton Keynes, MK1, MK2, MK3 and MK4 all point at Bletchley and MK40, MK41 and MK44 all point at Bedford.
What borders MK
MK sits next to NN (Northampton) to the north west, LU (Luton) to the south east, SG (Stevenage) to the east, HP (Hemel Hempstead) to the south and AL (St Albans) to the south east.
Its neighbours run in 4 different directions, so MK is landlocked by other postcode areas on most sides.
MK districts, settlements and water supply
| District | Principal settlement | Water company | Hosepipe ban status |
|---|---|---|---|
| MK1 | Bletchley | Anglian Water / Affinity Water | Depends on your supplier |
| MK2 | Bletchley | Anglian Water / Affinity Water | Depends on your supplier |
| MK3 | Bletchley | Anglian Water / Affinity Water | Depends on your supplier |
| MK4 | Bletchley | Anglian Water / Affinity Water | Depends on your supplier |
| MK5 | Milton Keynes | Anglian Water / Affinity Water | Depends on your supplier |
| MK6 | Milton Keynes | Anglian Water / Affinity Water | Depends on your supplier |
| MK7 | Woburn Sands | Anglian Water / Affinity Water | Depends on your supplier |
| MK8 | Milton Keynes | Anglian Water / Affinity Water | Depends on your supplier |
| MK9 | Milton Keynes | Anglian Water / Affinity Water | Depends on your supplier |
| MK10 | Milton Keynes | Anglian Water / Affinity Water | Depends on your supplier |
| MK11 | Milton Keynes | Anglian Water / Affinity Water | Depends on your supplier |
| MK12 | Milton Keynes | Anglian Water / Affinity Water | Depends on your supplier |
| MK13 | Milton Keynes | Anglian Water / Affinity Water | Depends on your supplier |
| MK14 | Milton Keynes | Anglian Water / Affinity Water | Depends on your supplier |
| MK15 | Milton Keynes | Anglian Water / Affinity Water | Depends on your supplier |
| MK16 | Newport Pagnell | Anglian Water / Affinity Water | Depends on your supplier |
| MK17 | Woburn Sands | Anglian Water / Affinity Water | Depends on your supplier |
| MK18 | Buckingham | Anglian Water / Affinity Water | Depends on your supplier |
| MK19 | Milton Keynes | Anglian Water / Affinity Water | Depends on your supplier |
| MK20 | Newport Pagnell | Anglian Water / Affinity Water | Depends on your supplier |
| MK40 | Bedford | Anglian Water / Affinity Water | Depends on your supplier |
| MK41 | Bedford | Anglian Water / Affinity Water | Depends on your supplier |
| MK42 | Kempston | Anglian Water / Affinity Water | Depends on your supplier |
| MK43 | Kempston | Anglian Water / Affinity Water | Depends on your supplier |
| MK44 | Bedford | Anglian Water / Affinity Water | Depends on your supplier |
| MK45 | Flitwick | Anglian Water / Affinity Water | Depends on your supplier |
| MK46 | Olney | Anglian Water / Affinity Water | Depends on your supplier |
| MK77 | Milton Keynes | Anglian Water / Affinity 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 MK
No water company covering MK 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 |
|---|---|---|---|---|
| MK1 | Not published by Anglian Water. Check with your supplier. | |||
| MK2 | Not published by Anglian Water. Check with your supplier. | |||
| MK3 | Not published by Anglian Water. Check with your supplier. | |||
| MK4 | Not published by Anglian Water. Check with your supplier. | |||
| MK5 | Not published by Anglian Water. Check with your supplier. | |||
| MK6 | Not published by Anglian Water. Check with your supplier. | |||
| MK7 | Not published by Anglian Water. Check with your supplier. | |||
| MK8 | Not published by Anglian Water. Check with your supplier. | |||
| MK9 | Not published by Anglian Water. Check with your supplier. | |||
| MK10 | Not published by Anglian Water. Check with your supplier. | |||
| MK11 | Not published by Anglian Water. Check with your supplier. | |||
| MK12 | Not published by Anglian Water. Check with your supplier. | |||
| MK13 | Not published by Anglian Water. Check with your supplier. | |||
| MK14 | Not published by Anglian Water. Check with your supplier. | |||
| MK15 | Not published by Anglian Water. Check with your supplier. | |||
| MK16 | Not published by Anglian Water. Check with your supplier. | |||
| MK17 | Not published by Anglian Water. Check with your supplier. | |||
| MK18 | Not published by Anglian Water. Check with your supplier. | |||
| MK19 | Not published by Anglian Water. Check with your supplier. | |||
| MK20 | Not published by Anglian Water. Check with your supplier. | |||
| MK40 | Not published by Anglian Water. Check with your supplier. | |||
| MK41 | Not published by Anglian Water. Check with your supplier. | |||
| MK42 | Not published by Anglian Water. Check with your supplier. | |||
| MK43 | Not published by Anglian Water. Check with your supplier. | |||
| MK44 | Not published by Anglian Water. Check with your supplier. | |||
| MK45 | Not published by Anglian Water. Check with your supplier. | |||
| MK46 | Not published by Anglian Water. Check with your supplier. | |||
| MK77 | Not published by Anglian 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 MK 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 MK area?
There are 28 MK postcode districts, running from MK1 to MK77, and they contain 16,215 live postcodes across 110 sectors.
What towns does the MK postcode area cover?
MK covers Milton Keynes, Bedford, Kempston, Bletchley, Flitwick and Woburn Sands. The area takes its name from Milton Keynes, and each district is listed with its settlement in the table on this page.
Which water company supplies MK postcodes?
Anglian Water supplies all 28 MK 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 MK5 and MK6 both say Milton Keynes?
MK5, MK6, MK8, MK9, MK10, MK11, MK12, MK13, MK14, MK15, MK19 and MK77 all serve Milton Keynes, 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 MK postcode map?
Yes. This page offers the MK 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.
Why is the MK area called Bletchley when it covers Flitwick?
MK takes its letters from Bletchley, where the sorting office that served the area was based when the code was allocated. Flitwick is the largest settlement in the area today, in MK45, but the area code follows the historic sorting geography rather than current population.
Which councils cover the MK postcode area?
MK reaches into Milton Keynes, Bedford, Central Bedfordshire, Buckinghamshire, Oxfordshire and West Northamptonshire. 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.