AL3 4 postcode sector in the AL3 district

AL3 4 is a sector of the AL3 district: every postcode that starts AL3 4. It has 186 postcodes in use, 4 of them large-user postcodes. A large-user postcode is one Royal Mail gives to a single address that gets a lot of mail.

Not sure what a sector is? UK postcode format explained.

Every postcode in the AL3 4 sector, by flood risk

Map of every postcode in the AL3 4 sector, by flood risk Of the 186 postcodes in the AL3 4 sector that ONS places, 2 have a home or business at high risk, 3 are at low risk at worst, 1 are at very low risk only and 180 are not on the Environment Agency's at-risk list. 2 postcodes lie beyond the edge and are listed under the map. Places named: Verulam. Drawn over roads, rivers and built-up areas. North is up; the scale bar is 250 m. A414A4147A5183 AL3 4AA: not on the flood risk listAL3 4AB: not on the flood risk listAL3 4AD: not on the flood risk listAL3 4AE: not on the flood risk listAL3 4AF: not on the flood risk listAL3 4AH: not on the flood risk listAL3 4AJ: not on the flood risk listAL3 4AP: not on the flood risk listAL3 4AR: not on the flood risk listAL3 4AS: not on the flood risk listAL3 4AT: not on the flood risk listAL3 4AU: not on the flood risk listAL3 4AW: not on the flood risk listAL3 4AY: not on the flood risk listAL3 4AZ: not on the flood risk listAL3 4BA: not on the flood risk listAL3 4BB: not on the flood risk listAL3 4BD: not on the flood risk listAL3 4BG: not on the flood risk listAL3 4BH: not on the flood risk listAL3 4BJ: not on the flood risk listAL3 4BL: not on the flood risk listAL3 4BN: not on the flood risk listAL3 4BQ: not on the flood risk listAL3 4BY: not on the flood risk listAL3 4BZ: not on the flood risk listAL3 4DA: not on the flood risk listAL3 4DD: not on the flood risk listAL3 4DE: not on the flood risk listAL3 4DG: not on the flood risk listAL3 4DH: not on the flood risk listAL3 4DJ: not on the flood risk listAL3 4DL: not on the flood risk listAL3 4DN: not on the flood risk listAL3 4DP: not on the flood risk listAL3 4DQ: not on the flood risk listAL3 4DR: not on the flood risk listAL3 4DW: not on the flood risk listAL3 4EA: not on the flood risk listAL3 4EB: not on the flood risk listAL3 4ED: not on the flood risk listAL3 4EH: not on the flood risk listAL3 4EL: not on the flood risk listAL3 4EP: not on the flood risk listAL3 4ER: not on the flood risk listAL3 4ES: not on the flood risk listAL3 4ET: not on the flood risk listAL3 4EW: not on the flood risk listAL3 4EZ: not on the flood risk listAL3 4FB: not on the flood risk listAL3 4FD: not on the flood risk listAL3 4GB: not on the flood risk listAL3 4GD: not on the flood risk listAL3 4GE: not on the flood risk listAL3 4GF: not on the flood risk listAL3 4GG: not on the flood risk listAL3 4GH: not on the flood risk listAL3 4GJ: not on the flood risk listAL3 4GL: not on the flood risk listAL3 4GN: not on the flood risk listAL3 4HA: not on the flood risk listAL3 4HB: not on the flood risk listAL3 4HD: not on the flood risk listAL3 4HE: not on the flood risk listAL3 4HG: not on the flood risk listAL3 4HH: not on the flood risk listAL3 4HL: not on the flood risk listAL3 4HN: not on the flood risk listAL3 4HW: not on the flood risk listAL3 4HX: not on the flood risk listAL3 4HY: not on the flood risk listAL3 4HZ: not on the flood risk listAL3 4JA: not on the flood risk listAL3 4JB: not on the flood risk listAL3 4JD: not on the flood risk listAL3 4JE: not on the flood risk listAL3 4JF: not on the flood risk listAL3 4JG: not on the flood risk listAL3 4JH: not on the flood risk listAL3 4JJ: not on the flood risk listAL3 4JL: not on the flood risk listAL3 4JN: not on the flood risk listAL3 4JP: not on the flood risk listAL3 4JQ: not on the flood risk listAL3 4JR: not on the flood risk listAL3 4JS: not on the flood risk listAL3 4JT: not on the flood risk listAL3 4JU: not on the flood risk listAL3 4JW: not on the flood risk listAL3 4JX: not on the flood risk listAL3 4JY: not on the flood risk listAL3 4JZ: not on the flood risk listAL3 4LA: not on the flood risk listAL3 4LD: not on the flood risk listAL3 4LP: not on the flood risk listAL3 4LR: not on the flood risk listAL3 4LS: not on the flood risk listAL3 4LT: not on the flood risk listAL3 4LU: not on the flood risk listAL3 4LW: not on the flood risk listAL3 4LX: not on the flood risk listAL3 4LY: not on the flood risk listAL3 4LZ: not on the flood risk listAL3 4NA: not on the flood risk listAL3 4NB: not on the flood risk listAL3 4ND: not on the flood risk listAL3 4NE: not on the flood risk listAL3 4NF: not on the flood risk listAL3 4NG: not on the flood risk listAL3 4NH: not on the flood risk listAL3 4NJ: not on the flood risk listAL3 4NQ: not on the flood risk listAL3 4NR: not on the flood risk listAL3 4PA: not on the flood risk listAL3 4PE: not on the flood risk listAL3 4PF: not on the flood risk listAL3 4PH: not on the flood risk listAL3 4PJ: not on the flood risk listAL3 4PN: not on the flood risk listAL3 4PQ: not on the flood risk listAL3 4PS: not on the flood risk listAL3 4PT: not on the flood risk listAL3 4PU: not on the flood risk listAL3 4PW: not on the flood risk listAL3 4PX: not on the flood risk listAL3 4PY: not on the flood risk listAL3 4PZ: not on the flood risk listAL3 4QA: not on the flood risk listAL3 4QB: not on the flood risk listAL3 4QD: not on the flood risk listAL3 4QE: not on the flood risk listAL3 4QF: not on the flood risk listAL3 4QG: not on the flood risk listAL3 4QH: not on the flood risk listAL3 4QJ: not on the flood risk listAL3 4QL: not on the flood risk listAL3 4QN: not on the flood risk listAL3 4QP: not on the flood risk listAL3 4QQ: not on the flood risk listAL3 4QR: not on the flood risk listAL3 4QS: not on the flood risk listAL3 4QT: not on the flood risk listAL3 4QU: not on the flood risk listAL3 4QW: not on the flood risk listAL3 4QY: not on the flood risk listAL3 4RA: not on the flood risk listAL3 4RB: not on the flood risk listAL3 4RF: not on the flood risk listAL3 4RQ: not on the flood risk listAL3 4RS: not on the flood risk listAL3 4RT: not on the flood risk listAL3 4RU: not on the flood risk listAL3 4RX: not on the flood risk listAL3 4RY: not on the flood risk listAL3 4RZ: not on the flood risk listAL3 4SA: not on the flood risk listAL3 4SB: not on the flood risk listAL3 4SE: not on the flood risk listAL3 4SH: not on the flood risk listAL3 4SL: not on the flood risk listAL3 4SN: not on the flood risk listAL3 4SQ: not on the flood risk listAL3 4SS: not on the flood risk listAL3 4ST: not on the flood risk listAL3 4SU: not on the flood risk listAL3 4SW: not on the flood risk listAL3 4SX: not on the flood risk listAL3 4SY: not on the flood risk listAL3 4SZ: not on the flood risk listAL3 4TA: not on the flood risk listAL3 4TB: not on the flood risk listAL3 4TF: not on the flood risk listAL3 4TG: not on the flood risk listAL3 4TH: not on the flood risk listAL3 4TL: not on the flood risk listAL3 4TN: not on the flood risk listAL3 4TQ: not on the flood risk listAL3 4TZ: not on the flood risk listAL3 4SD: very low flood risk onlyAL3 4SF: low flood risk at worstAL3 4SG: low flood risk at worstAL3 4SP: low flood risk at worstAL3 4HJ: high flood riskAL3 4SJ: high flood risk Verulam Map of every postcode in the AL3 4 sector, by flood risk Of the 186 postcodes in the AL3 4 sector that ONS places, 2 have a home or business at high risk, 3 are at low risk at worst, 1 are at very low risk only and 180 are not on the Environment Agency's at-risk list. 2 postcodes lie beyond the edge and are listed under the map. Places named: Verulam. Drawn over roads, rivers and built-up areas. North is up; the scale bar is 500 m. A414 Verulam
  • A home or business at high risk: 2
  • At medium risk at worst: 0
  • At low risk at worst: 3
  • At very low risk only: 1
  • Not on the at-risk list: 180

Of the 186 postcodes in the AL3 4 sector that ONS places, 2 have a home or business at high risk, 3 are at low risk at worst, 1 are at very low risk only and 180 are not on the Environment Agency's at-risk list.

Each mark is a postcode's centre point as ONS gives it, not a building. Press one to see its postcode and open its page. No boundary is drawn. Where marks overlap, the one first in the key is drawn; the counts include every postcode. Names in italics are council wards: we hold no town or village names here.

Source: Office for National Statistics (ONS) Postcode Directory, August 2026, loaded 20 October 2026, the centre point of each postcode; flood risk: Environment Agency, published 6 July 2026; roads, rivers and built-up areas: Contains OS data © Crown copyright and database right 2026. Drawn by us. Street map: Ordnance Survey, OS Open Zoomstack, Open Government Licence v3.0, drawn with MapLibre. How we use them

The postcodes at high risk

Beside each: how many of its homes and businesses the Environment Agency puts at that risk.

AL3 4SJ1 at high riskAL3 4HJ1 at high risk

2 further out, not drawn

These postcodes lie well apart from the rest, so the map is drawn without them to show the rest closer; they are in every count.

AL3 4ALAL3 4HR

What do homes sell for in AL3 4?

Homes in AL3 4 sold for a typical £760,000 in the 12 months to August 2026, across 62 sales, down 3.2% on the 12 months before, HM Land Registry's figures show.

£760,000 typical price, the 12 months to August 2026
£785,000 12 months to August 2025
▼ down 3.2% on the 12 months before
  • Detached £1,162,500 16 sales
  • Semi-detached £865,000 8 sales
  • Terraced £755,000 26 sales
  • Flat or maisonette £417,751 12 sales

Each bar is that kind's typical price, against the most expensive kind here.

Standard sales of homes at market value at the postcodes that start AL3 4. A typical price is the median, the middle sale, given from 5 sales or more.

How we work this out: house prices by postcode

Source: HM Land Registry Price Paid Data, files dated 28 September 2026. Contains HM Land Registry data © Crown copyright and database right 2021. This data is licensed under the Open Government Licence v3.0. How we use it

Postcodes in AL3 4

Pick a postcode to see its council and MP, broadband, flood risk, what homes sell for, council tax, the nearest schools and stations, and crime around it.

AL3 4AAAL3 4ABAL3 4ADAL3 4AEAL3 4AFAL3 4AHAL3 4AJAL3 4ALAL3 4APAL3 4ARAL3 4ASAL3 4ATAL3 4AUAL3 4AWAL3 4AYAL3 4AZAL3 4BAAL3 4BBAL3 4BDAL3 4BGAL3 4BHAL3 4BJAL3 4BLAL3 4BNAL3 4BQAL3 4BYAL3 4BZAL3 4DAAL3 4DDAL3 4DEAL3 4DGAL3 4DHAL3 4DJAL3 4DLAL3 4DNAL3 4DPAL3 4DQAL3 4DRAL3 4DWAL3 4EAAL3 4EBAL3 4EDAL3 4EHAL3 4ELAL3 4EPAL3 4ERAL3 4ESAL3 4ETAL3 4EWAL3 4EZAL3 4FBAL3 4FDAL3 4GBAL3 4GDAL3 4GEAL3 4GFAL3 4GGAL3 4GHAL3 4GJAL3 4GLAL3 4GNAL3 4HAAL3 4HBAL3 4HDAL3 4HEAL3 4HGAL3 4HHAL3 4HJAL3 4HLAL3 4HNAL3 4HRAL3 4HWAL3 4HXAL3 4HYAL3 4HZAL3 4JAAL3 4JBAL3 4JDAL3 4JEAL3 4JFAL3 4JGAL3 4JHAL3 4JJAL3 4JLAL3 4JNAL3 4JPAL3 4JQAL3 4JRAL3 4JSAL3 4JTAL3 4JUAL3 4JWAL3 4JXAL3 4JYAL3 4JZAL3 4LAAL3 4LDAL3 4LPAL3 4LRAL3 4LSAL3 4LTAL3 4LUAL3 4LWAL3 4LXAL3 4LYAL3 4LZAL3 4NAAL3 4NBAL3 4NDAL3 4NEAL3 4NFAL3 4NGAL3 4NHAL3 4NJAL3 4NQAL3 4NRAL3 4PAAL3 4PEAL3 4PFAL3 4PHAL3 4PJAL3 4PNAL3 4PQAL3 4PSAL3 4PTAL3 4PUAL3 4PWAL3 4PXAL3 4PYAL3 4PZAL3 4QAAL3 4QBAL3 4QDAL3 4QEAL3 4QFAL3 4QGAL3 4QHAL3 4QJAL3 4QLAL3 4QNAL3 4QPAL3 4QQAL3 4QRAL3 4QSAL3 4QTAL3 4QUAL3 4QWAL3 4QYAL3 4RAAL3 4RBAL3 4RFAL3 4RQAL3 4RSAL3 4RTAL3 4RUAL3 4RXAL3 4RYAL3 4RZAL3 4SAAL3 4SBAL3 4SDAL3 4SEAL3 4SFAL3 4SGAL3 4SHAL3 4SJAL3 4SLAL3 4SNAL3 4SPAL3 4SQAL3 4SSAL3 4STAL3 4SUAL3 4SWAL3 4SXAL3 4SYAL3 4SZAL3 4TAAL3 4TBAL3 4TFAL3 4TGAL3 4THAL3 4TLAL3 4TNAL3 4TQAL3 4TZ

Source: Office for National Statistics (ONS) Postcode Directory, August 2026, loaded 20 October 2026. Postcodes that have ended are not listed. See all our data sources

What council am I in? The council, borough or local authority for a postcode, and the county council where there is one. What ward am I in? The ward for a postcode, with its council, constituency and parish.

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