CM20 postcode area guide — East Hertfordshire
House prices, crime, broadband speeds, mobile signal, schools and demographics for the CM20 postcode district in East Hertfordshire — every official dataset on one page.
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Where is CM20?
Broadband & internet speeds in CM20
Strong coverage
Superfast (30Mb+)
88.9%
Ultrafast (300Mb+)
71.2%
Gigabit-capable
67.4%
Below USO (10Mb)
0%
Broadband availability in the CM20 postcode district (East Hertfordshire) is Strong — superfast is near-universal and gigabit is rolling out. Across the 565 postcodes Ofcom measures in CM20, superfast broadband (30 Mbit/s or faster) reaches 88.9% of premises and gigabit-capable lines are available to 67.4%.
Around 0% of premises in CM20 fall below the Universal Service Obligation (a minimum of 10 Mbit/s download and 1 Mbit/s upload), so the overwhelming majority of homes and businesses here can already order a decent fixed line. For a business that depends on its connection, the figures that matter most are gigabit and full-fibre availability — the symmetric, low-contention services we quote leased lines and FTTP against.
Sample postcodes in CM20
| Postcode | Superfast | Gigabit |
|---|---|---|
| CM20 1AA | 0% | 0% |
| CM20 1AB | 0% | 0% |
| CM20 1AF | 100% | 0% |
| CM20 1AG | 100% | 0% |
| CM20 1AJ | 12.5% | 0% |
| CM20 1AN | 0% | 0% |
| CM20 1AQ | 0% | 0% |
| CM20 1AR | 100% | 0% |
| CM20 1AS | 100% | 0% |
| CM20 1AT | 100% | 0% |
Run a speed test to see what you're actually getting, or check your exact postcode.
Mobile signal around East Hertfordshire
Ofcom's coverage model for the wider East Hertfordshire district (71,670 premises):
4G indoors — all networks
87.2%
4G outdoors — all networks
98.8%
5G outdoors — all networks
27.7%
Voice indoors — all networks
90.2%
Signal varies street by street — use the mobile coverage checker to compare EE, O2, Three and Vodafone at an exact postcode.
Crime in CM20
Police recorded 475 incidents within about a mile of the centre of CM20 in May 2026 (latest published street-level data). The breakdown:
| Category | Incidents | Share |
|---|---|---|
| Violence & sexual offences | 174 | 36.6% |
| Shoplifting | 53 | 11.2% |
| Anti-social behaviour | 46 | 9.7% |
| Criminal damage & arson | 46 | 9.7% |
| Public order | 46 | 9.7% |
| Other theft | 22 | 4.6% |
| Vehicle crime | 16 | 3.4% |
| Drugs | 15 | 3.2% |
Raw counts favour busy town centres — a high street with shops and nightlife records more incidents than a residential cul-de-sac. Source: police.uk open data (point sample around the district centroid).
House prices in CM20
Based on 198 sales registered with HM Land Registry in the last 12 months, the median sold price in CM20 is £315,000, up 3.3% on the previous year (£305,000).
Detached
£582,000
9 sales
Semi-detached
£375,000
13 sales
Terraced
£330,000
96 sales
Flat / maisonette
£200,000
71 sales
Latest recorded sales in CM20
| Date | Price | Type | Street | Postcode |
|---|---|---|---|---|
| 27 May 2026 | £200,000 | Flat | Tanys Dell | CM20 2LJ |
| 22 May 2026 | £195,000 | Flat | Torkildsen Way | CM20 1AY |
| 15 May 2026 | £200,000 | Flat | Bromley Close | CM20 2GD |
| 13 May 2026 | £185,000 | Flat | Hornbeams | CM20 1PG |
| 11 May 2026 | £365,000 | Terraced | St Michaels Close | CM20 3QH |
| 1 May 2026 | £320,000 | Terraced | Green Hills | CM20 3SX |
| 30 Apr 2026 | £560,000 | Detached | Terlings Avenue | CM20 2FP |
| 29 Apr 2026 | £360,000 | Terraced | Lavender Close | CM20 3QJ |
| 27 Apr 2026 | £325,000 | Terraced | Churchfield | CM20 3DD |
| 22 Apr 2026 | £338,000 | Terraced | Green Hills | CM20 3SZ |
Contains HM Land Registry data © Crown copyright and database right 2026, licensed under the Open Government Licence v3.0.
Who lives here? East Hertfordshire demographics
Census 2021 figures for the wider East Hertfordshire district (150,155 residents, 62,023 households):
| Age profile | |
|---|---|
| Under 15 | 19.3% |
| 15–29 | 21.1% |
| 30–44 | 20.5% |
| 45–64 | 20.9% |
| 65+ | 18.2% |
| Housing tenure | |
|---|---|
| Owner-occupied | 69.4% |
| Private rented | 16.1% |
| Social rented | 11.4% |
Source: ONS Census 2021 (district level — the finest openly licensed cut we republish). © Crown copyright, OGL v3.0.
Schools in and around CM20
| School | Phase | Ages | Pupils | Postcode |
|---|---|---|---|---|
| Burnt Mill Academy | Secondary | 11–16 | 959 | CM20 2NR |
| Cooks Spinney Primary Academy and Nursery | Primary | 3–11 | 443 | CM20 3BW |
| Tany's Dell Primary School and Nursery | Primary | 3–11 | 437 | CM20 2LS |
| Freshwaters Primary Academy | Primary | 3–11 | 413 | CM20 3QA |
| The Downs Primary School and Nursery | Primary | 3–11 | 362 | CM20 3RB |
| Little Parndon Primary Academy | Primary | 4–11 | 352 | CM20 1PU |
| Bmat Stem Academy | Secondary | 14–19 | 240 | CM20 3EZ |
| St Alban's Catholic Academy | Primary | 3–11 | 227 | CM20 2NP |
Source: DfE Get Information about Schools (England & Wales). Check Ofsted report cards for inspection detail — headline one-word grades were retired in 2024.
Food hygiene ratings in CM20
273 rated food businesses operate in CM20. 189 hold the top rating of 5, 32 are rated 4, and 6 are rated 2 or below.
Among the 5-rated: 1:1 Diet By Cambridge Weight Plan - Tinette Weinman, Acupuncture & Herbcare, ADC Harlow, Adil Adori, Aldi.
Source: Food Standards Agency, food hygiene ratings (FHRS) open data.
Energy performance (EPC) in CM20
From a sample of 362 Energy Performance Certificates across 9 CM20 postcodes, the most common rating is band D (average band C). 56% of sampled homes are rated C or better.
Band A
0%
Band B
24%
Band C
31%
Band D
40%
Band E
5%
Source: MHCLG Energy Performance of Buildings Data (England & Wales), sampled at postcode level and refreshed monthly. Individual certificates are on each postcode’s page.
Phone area codes for East Hertfordshire
Landlines around CM20 typically use:
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What's it like living in CM20?
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Moving to CM20? Sort your connectivity first
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Postcodes in CM20
Neighbouring districts
All Chelmsford (CM) postcode districts ›
Frequently asked questions
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Sources: HM Land Registry Price Paid Data, police.uk street-level crime, Ofcom Connected Nations, ONS Census 2021, DfE Get Information about Schools, Food Standards Agency FHRS — all © Crown copyright, licensed under the Open Government Licence v3.0. Figures are area aggregates; individual addresses vary. Energy performance (EPC) data will be added when our Open Data Communities registration is approved.