SY postcode district map, Shrewsbury
Supplier statuses last checked .
We’re re-checking Welsh Water. Its last confirmed status is still shown here, because hiding a restriction we cannot currently re-read is the more expensive mistake, last confirmed 29 days ago.
The SY postcode area covers 26 districts and 14,641 live postcodes, from SY1 to SY99. It is centred on Shrewsbury and also covers Oswestry, Whitchurch, Aberystwyth, Wem and Y Trallwng.
Districts here average 563 postcodes.
Where the SY districts sit
3 districts are plotted without a label where labels would overlap; every one is in the table below.
Where SY sits
It is administratively fragmented, reaching into Shropshire, Powys, Wrexham and Ceredigion and 4 other authorities.
SY spans the border: 9,839 of its postcodes are in England and 4,802 in Wales, about 33 per cent. That matters here in a way it does not on a plain postcode map, because water is regulated separately either side of it. In England the Environment Agency oversees drought and abstraction; in Wales it is Natural Resources Wales, and restrictions are set by whichever company supplies the address, not by which country it sits in.
Water supply across SY
All 26 SY districts are supplied by Severn Trent, which is notable at this size: an area with this many districts usually crosses at least one supply boundary, and this one does not.
We are re-checking Severn Trent's status. It was last confirmed on 18 August 2026 as voluntary appeal, and until it is confirmed again this page does not assert a current position for it.
The shape of the SY area
The districts are wildly uneven: SY3 holds 1,113 postcodes around Shrewsbury and SY99 holds 8, a ratio of about 139 to one. They divide into 83 sectors.
The numbering is not continuous. SY runs up to 99 but has only 26 districts, so 73 numbers are unused:.
Several districts share a settlement, which is a common source of confusion when a form rejects an address: SY1, SY2, SY3, SY5 and SY99 all point at Shrewsbury, SY10 and SY11 all point at Oswestry and SY13 and SY14 all point at Whitchurch.
What borders SY
SY sits next to LL (Wrexham) to the north west, LD (Llandrindod Wells) to the south, TF (Telford) to the east, HR (Hereford) to the south east and CH (Chester) to the north.
Its neighbours run in 5 different directions, so SY is landlocked by other postcode areas on most sides.
SY districts, settlements and water supply
| District | Principal settlement | Water company | Hosepipe ban status |
|---|---|---|---|
| SY1 | Shrewsbury | Severn Trent / Welsh Water / Hafren Dyfrdwy | Check with your supplier |
| SY2 | Shrewsbury | Severn Trent / Welsh Water / Hafren Dyfrdwy | Check with your supplier |
| SY3 | Shrewsbury | Severn Trent / Welsh Water / Hafren Dyfrdwy | Check with your supplier |
| SY4 | Wem | Severn Trent / Welsh Water / Hafren Dyfrdwy | Check with your supplier |
| SY5 | Shrewsbury | Severn Trent / Welsh Water / Hafren Dyfrdwy | Check with your supplier |
| SY6 | Church Stretton | Severn Trent / Welsh Water / Hafren Dyfrdwy | Check with your supplier |
| SY7 | Craven Arms | Severn Trent / Welsh Water / Hafren Dyfrdwy | Check with your supplier |
| SY8 | Ludlow | Severn Trent / Welsh Water / Hafren Dyfrdwy | Check with your supplier |
| SY9 | Bishop's Castle | Severn Trent / Welsh Water / Hafren Dyfrdwy | Check with your supplier |
| SY10 | Oswestry | Severn Trent / Welsh Water / Hafren Dyfrdwy | Check with your supplier |
| SY11 | Oswestry | Severn Trent / Welsh Water / Hafren Dyfrdwy | Check with your supplier |
| SY12 | Ellesmere | Severn Trent / Welsh Water / Hafren Dyfrdwy | Check with your supplier |
| SY13 | Whitchurch | Severn Trent / Welsh Water / Hafren Dyfrdwy | Check with your supplier |
| SY14 | Whitchurch | Severn Trent / Welsh Water / Hafren Dyfrdwy | Check with your supplier |
| SY15 | Trefaldwyn | Severn Trent / Welsh Water / Hafren Dyfrdwy | Check with your supplier |
| SY16 | Y Drenewydd | Severn Trent / Welsh Water / Hafren Dyfrdwy | Check with your supplier |
| SY17 | Llanidloes | Severn Trent / Welsh Water / Hafren Dyfrdwy | Check with your supplier |
| SY18 | Llanidloes | Severn Trent / Welsh Water / Hafren Dyfrdwy | Check with your supplier |
| SY19 | Machynlleth | Severn Trent / Welsh Water / Hafren Dyfrdwy | Check with your supplier |
| SY20 | Machynlleth | Severn Trent / Welsh Water / Hafren Dyfrdwy | Check with your supplier |
| SY21 | Y Trallwng | Severn Trent / Welsh Water / Hafren Dyfrdwy | Check with your supplier |
| SY22 | Llanfyllin | Severn Trent / Welsh Water / Hafren Dyfrdwy | Check with your supplier |
| SY23 | Aberystwyth | Severn Trent / Welsh Water / Hafren Dyfrdwy | Check with your supplier |
| SY24 | Aberystwyth | Severn Trent / Welsh Water / Hafren Dyfrdwy | Check with your supplier |
| SY25 | Tregaron | Severn Trent / Welsh Water / Hafren Dyfrdwy | Check with your supplier |
| SY99 | Shrewsbury | Severn Trent / Welsh Water / Hafren Dyfrdwy | Check with 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 SY
No water company covering SY 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 |
|---|---|---|---|---|
| SY1 | Not published by Severn Trent. Check with your supplier. | |||
| SY2 | Not published by Severn Trent. Check with your supplier. | |||
| SY3 | Not published by Severn Trent. Check with your supplier. | |||
| SY4 | Not published by Severn Trent. Check with your supplier. | |||
| SY5 | Not published by Severn Trent. Check with your supplier. | |||
| SY6 | Not published by Severn Trent. Check with your supplier. | |||
| SY7 | Not published by Severn Trent. Check with your supplier. | |||
| SY8 | Not published by Severn Trent. Check with your supplier. | |||
| SY9 | Not published by Severn Trent. Check with your supplier. | |||
| SY10 | Not published by Severn Trent. Check with your supplier. | |||
| SY11 | Not published by Severn Trent. Check with your supplier. | |||
| SY12 | Not published by Severn Trent. Check with your supplier. | |||
| SY13 | Not published by Severn Trent. Check with your supplier. | |||
| SY14 | Not published by Severn Trent. Check with your supplier. | |||
| SY15 | Not published by Severn Trent. Check with your supplier. | |||
| SY16 | Not published by Severn Trent. Check with your supplier. | |||
| SY17 | Not published by Severn Trent. Check with your supplier. | |||
| SY18 | Not published by Severn Trent. Check with your supplier. | |||
| SY19 | Not published by Severn Trent. Check with your supplier. | |||
| SY20 | Not published by Severn Trent. Check with your supplier. | |||
| SY21 | Not published by Severn Trent. Check with your supplier. | |||
| SY22 | Not published by Severn Trent. Check with your supplier. | |||
| SY23 | Not published by Severn Trent. Check with your supplier. | |||
| SY24 | Not published by Severn Trent. Check with your supplier. | |||
| SY25 | Not published by Severn Trent. Check with your supplier. | |||
| SY99 | Not published by Severn Trent. 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 SY 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 SY area?
There are 26 SY postcode districts, running from SY1 to SY99, and they contain 14,641 live postcodes across 83 sectors.
What towns does the SY postcode area cover?
SY covers Shrewsbury, Oswestry, Whitchurch, Aberystwyth, Wem and Y Trallwng. The area takes its name from Shrewsbury, and each district is listed with its settlement in the table on this page.
Which water company supplies SY postcodes?
Severn Trent supplies all 26 SY 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.
Is the SY postcode area in England or Wales?
Both. 9,839 SY postcodes are in England and 4,802 are in Wales. The postcode does not decide which applies: your water company does, and water is regulated separately either side of the border.
Why do SY1 and SY2 both say Shrewsbury?
SY1, SY2, SY3, SY5 and SY99 all serve Shrewsbury, 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 SY postcode map?
Yes. This page offers the SY 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 SY postcode area?
SY reaches into Shropshire, Powys, Wrexham, Ceredigion, County of Herefordshire, Cheshire East, Telford and Wrekin and Gwynedd. 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.