RH postcode district map, Redhill
Supplier statuses last checked .
The RH postcode area covers 21 districts and 16,366 live postcodes, from RH1 to RH77. It is centred on Crawley and also covers Horsham, East Grinstead, Dorking, Redhill and Haywards Heath.
Districts here average 779 postcodes.
Where the RH districts sit
3 districts are plotted without a label where labels would overlap; every one is in the table below.
Where RH sits
It falls across West Sussex, Surrey and East Sussex.
Water supply across RH
All 21 RH districts are supplied by South East Water. That makes RH simple in a way many areas are not: one company, one set of rules, one status to check.
South East Water has a hosepipe ban in force from 3 July 2026, covering the whole of RH.
The shape of the RH area
The districts are wildly uneven: RH10 holds 1,918 postcodes around Crawley and RH77 holds 16, a ratio of about 120 to one. They divide into 87 sectors.
The numbering is not continuous. RH runs up to 77 but has only 21 districts, so 56 numbers are unused:.
Several districts share a settlement, which is a common source of confusion when a form rejects an address: RH3, RH4 and RH5 all point at Dorking, RH7, RH18 and RH19 all point at East Grinstead and RH10, RH11 and RH77 all point at Crawley.
What borders RH
RH sits next to BN (Brighton and Hove) to the south, CR (Warlingham) to the north, SM (Ewell) to the north, KT (Esher) to the north and GU (Guildford) to the west.
RH districts, settlements and water supply
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 RH
No water company covering RH 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 |
|---|---|---|---|---|
| RH1 | Not published by South East Water. Check with your supplier. | |||
| RH2 | Not published by South East Water. Check with your supplier. | |||
| RH3 | Not published by South East Water. Check with your supplier. | |||
| RH4 | Not published by South East Water. Check with your supplier. | |||
| RH5 | Not published by South East Water. Check with your supplier. | |||
| RH6 | Not published by South East Water. Check with your supplier. | |||
| RH7 | Not published by South East Water. Check with your supplier. | |||
| RH8 | Not published by South East Water. Check with your supplier. | |||
| RH9 | Not published by South East Water. Check with your supplier. | |||
| RH10 | Not published by South East Water. Check with your supplier. | |||
| RH11 | Not published by South East Water. Check with your supplier. | |||
| RH12 | Not published by South East Water. Check with your supplier. | |||
| RH13 | Not published by South East Water. Check with your supplier. | |||
| RH14 | Not published by South East Water. Check with your supplier. | |||
| RH15 | Not published by South East Water. Check with your supplier. | |||
| RH16 | Not published by South East Water. Check with your supplier. | |||
| RH17 | Not published by South East Water. Check with your supplier. | |||
| RH18 | Not published by South East Water. Check with your supplier. | |||
| RH19 | Not published by South East Water. Check with your supplier. | |||
| RH20 | Not published by South East Water. Check with your supplier. | |||
| RH77 | Not published by South East 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 RH 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 RH area?
There are 21 RH postcode districts, running from RH1 to RH77, and they contain 16,366 live postcodes across 87 sectors.
What towns does the RH postcode area cover?
RH covers Crawley, Horsham, East Grinstead, Dorking, Redhill and Haywards Heath. The area takes its name from Crawley, and each district is listed with its settlement in the table on this page.
Which water company supplies RH postcodes?
South East Water supplies all 21 RH 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 RH3 and RH4 both say Dorking?
RH3, RH4 and RH5 all serve Dorking, 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 RH postcode map?
Yes. This page offers the RH 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 RH area called Redhill when it covers Crawley?
RH takes its letters from Redhill, where the sorting office that served the area was based when the code was allocated. Crawley is the largest settlement in the area today, in RH10, but the area code follows the historic sorting geography rather than current population.
Which councils cover the RH postcode area?
RH reaches into West Sussex, Surrey and East Sussex. 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.