SM postcode district map, Ewell
Supplier statuses last checked .
The SM postcode area covers 7 districts and 4,326 live postcodes, from SM1 to SM7. It is centred on Banstead and also covers Ewell.
Districts here average 618 postcodes.
Where the SM districts sit
Where SM sits
It falls across Greater London and Surrey.
Water supply across SM
All 7 SM districts are supplied by Thames Water. That makes SM simple in a way many areas are not: one company, one set of rules, one status to check.
Thames Water has a hosepipe ban in force from 23 July 2026, covering the whole of SM.
The shape of the SM area
SM1 is the largest district with 843 postcodes around Ewell, and SM3 the smallest with 379. The area divides into 28 postcode sectors.
District by district: SM1 serves Ewell, SM2 serves Banstead, SM3 serves Ewell, SM4 serves Ewell, SM5 serves Banstead, SM6 serves Banstead and SM7 serves Banstead.
Several districts share a settlement, which is a common source of confusion when a form rejects an address: SM2, SM5, SM6 and SM7 all point at Banstead and SM1, SM3 and SM4 all point at Ewell.
What borders SM
SM sits next to CR (Warlingham) to the east, SW (City of Westminster) to the north, KT (Esher) to the west, SE (City of London) to the north east and W (London) to the north.
Its neighbours run in 4 different directions, so SM is landlocked by other postcode areas on most sides.
SM districts, settlements and water supply
| District | Principal settlement | Water company | Hosepipe ban status |
|---|---|---|---|
| SM1 | Ewell | Thames Water / SES Water | Depends on your supplier |
| SM2 | Banstead | Thames Water / SES Water | Depends on your supplier |
| SM3 | Ewell | Thames Water / SES Water | Depends on your supplier |
| SM4 | Ewell | Thames Water / SES Water | Depends on your supplier |
| SM5 | Banstead | Thames Water / SES Water | Depends on your supplier |
| SM6 | Banstead | Thames Water / SES Water | Depends on your supplier |
| SM7 | Banstead | Thames Water / SES 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 SM
No water company covering SM 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 |
|---|---|---|---|---|
| SM1 | Not published by Thames Water. Check with your supplier. | |||
| SM2 | Not published by Thames Water. Check with your supplier. | |||
| SM3 | Not published by Thames Water. Check with your supplier. | |||
| SM4 | Not published by Thames Water. Check with your supplier. | |||
| SM5 | Not published by Thames Water. Check with your supplier. | |||
| SM6 | Not published by Thames Water. Check with your supplier. | |||
| SM7 | Not published by Thames 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 SM 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 SM area?
There are 7 SM postcode districts, running from SM1 to SM7, and they contain 4,326 live postcodes across 28 sectors.
What towns does the SM postcode area cover?
SM covers Banstead and Ewell. The area takes its name from Banstead, and each district is listed with its settlement in the table on this page.
Which water company supplies SM postcodes?
Thames Water supplies all 7 SM 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 SM2 and SM5 both say Banstead?
SM2, SM5, SM6 and SM7 all serve Banstead, 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 SM postcode map?
Yes. This page offers the SM 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 SM postcode area?
SM reaches into Greater London and Surrey. 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.
How many postcode sectors are in SM?
SM contains 28 postcode sectors across its 7 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.