AL9 postcode district: Brookmans Park and around, Hertfordshire

AL9 is a postcode district in Hertfordshire, with 429 postcodes in use in 3 sectors. It has postcodes in Brookmans Park, Hatfield and Welham Green. It is split between 2 councils: Welwyn Hatfield (427 postcodes) and East Hertfordshire (2).

Postcodes in use
429
Sectors
3
Councils
2 councils
Places
3 places

Source: Office for National Statistics (ONS) Postcode Directory, August 2026, loaded 20 October 2026. See all our data sources

Every postcode in AL9, by flood risk

Map of every postcode in AL9, by flood risk Of the 429 postcodes in AL9 that ONS places, 15 have a home or business at high risk, 6 are at medium risk at worst, 5 are at low risk at worst, 1 are at very low risk only and 402 are not on the Environment Agency's at-risk list. Places named: Brookmans Park, Hatfield, Welham Green. Drawn over roads, rivers and built-up areas. North is up; the scale bar is 1 km. A414A1001 AL9 5AB: not on the flood risk listAL9 5AD: not on the flood risk listAL9 5AE: not on the flood risk listAL9 5AF: not on the flood risk listAL9 5AH: not on the flood risk listAL9 5AJ: not on the flood risk listAL9 5AL: not on the flood risk listAL9 5AP: not on the flood risk listAL9 5AS: not on the flood risk listAL9 5AT: not on the flood risk listAL9 5AX: not on the flood risk listAL9 5AY: not on the flood risk listAL9 5AZ: not on the flood risk listAL9 5BD: not on the flood risk listAL9 5BG: not on the flood risk listAL9 5BL: not on the flood risk listAL9 5BT: not on the flood risk listAL9 5BW: not on the flood risk listAL9 5BX: not on the flood risk listAL9 5BY: not on the flood risk listAL9 5BZ: not on the flood risk listAL9 5DA: not on the flood risk listAL9 5DB: not on the flood risk listAL9 5DE: not on the flood risk listAL9 5DF: not on the flood risk listAL9 5DH: not on the flood risk listAL9 5DJ: not on the flood risk listAL9 5DL: not on the flood risk listAL9 5DN: not on the flood risk listAL9 5DP: not on the flood risk listAL9 5DQ: not on the flood risk listAL9 5DR: not on the flood risk listAL9 5DS: not on the flood risk listAL9 5DU: not on the flood risk listAL9 5DW: not on the flood risk listAL9 5DX: not on the flood risk listAL9 5DY: not on the flood risk listAL9 5DZ: not on the flood risk listAL9 5EA: not on the flood risk listAL9 5EB: not on the flood risk listAL9 5ED: not on the flood risk listAL9 5EF: not on the flood risk listAL9 5EG: not on the flood risk listAL9 5EH: not on the flood risk listAL9 5EL: not on the flood risk listAL9 5EN: not on the flood risk listAL9 5EP: not on the flood risk listAL9 5ER: not on the flood risk listAL9 5ET: not on the flood risk listAL9 5EU: not on the flood risk listAL9 5EX: not on the flood risk listAL9 5EY: not on the flood risk listAL9 5EZ: not on the flood risk listAL9 5FA: not on the flood risk listAL9 5FB: not on the flood risk listAL9 5FD: not on the flood risk listAL9 5HA: not on the flood risk listAL9 5HB: not on the flood risk listAL9 5HE: not on the flood risk listAL9 5HF: not on the flood risk listAL9 5HG: not on the flood risk listAL9 5HH: not on the flood risk listAL9 5HJ: not on the flood risk listAL9 5HL: not on the flood risk listAL9 5HN: not on the flood risk listAL9 5HQ: not on the flood risk listAL9 5HW: not on the flood risk listAL9 5HX: not on the flood risk listAL9 5HY: not on the flood risk listAL9 5JA: not on the flood risk listAL9 5JF: not on the flood risk listAL9 5JG: not on the flood risk listAL9 5JJ: not on the flood risk listAL9 5JN: not on the flood risk listAL9 5JX: not on the flood risk listAL9 5JY: not on the flood risk listAL9 5LP: not on the flood risk listAL9 5LR: not on the flood risk listAL9 5NA: not on the flood risk listAL9 5NF: not on the flood risk listAL9 5NG: not on the flood risk listAL9 5NH: not on the flood risk listAL9 5NJ: not on the flood risk listAL9 5NL: not on the flood risk listAL9 5NN: not on the flood risk listAL9 5NQ: not on the flood risk listAL9 5NU: not on the flood risk listAL9 5NW: not on the flood risk listAL9 5NX: not on the flood risk listAL9 5NZ: not on the flood risk listAL9 5PA: not on the flood risk listAL9 5PE: not on the flood risk listAL9 5PF: not on the flood risk listAL9 5PH: not on the flood risk listAL9 5PL: not on the flood risk listAL9 5PQ: not on the flood risk listAL9 5RB: not on the flood risk listAL9 5RE: not on the flood risk listAL9 5RF: not on the flood risk listAL9 5RH: not on the flood risk listAL9 5RL: not on the flood risk listAL9 5RQ: not on the flood risk listAL9 5SA: not on the flood risk listAL9 5SB: not on the flood risk listAL9 5SD: not on the flood risk listAL9 5SF: not on the flood risk listAL9 6AB: not on the flood risk listAL9 6AE: not on the flood risk listAL9 6AF: not on the flood risk listAL9 6AG: not on the flood risk listAL9 6AH: not on the flood risk listAL9 6AJ: not on the flood risk listAL9 6AL: not on the flood risk listAL9 6AN: not on the flood risk listAL9 6AP: not on the flood risk listAL9 6AQ: not on the flood risk listAL9 6AR: not on the flood risk listAL9 6AT: not on the flood risk listAL9 6AU: not on the flood risk listAL9 6AY: not on the flood risk listAL9 6BA: not on the flood risk listAL9 6BL: not on the flood risk listAL9 6BN: not on the flood risk listAL9 6BP: not on the flood risk listAL9 6BS: not on the flood risk listAL9 6DA: not on the flood risk listAL9 6DB: not on the flood risk listAL9 6DD: not on the flood risk listAL9 6DE: not on the flood risk listAL9 6DF: not on the flood risk listAL9 6DG: not on the flood risk listAL9 6DH: not on the flood risk listAL9 6DJ: not on the flood risk listAL9 6DL: not on the flood risk listAL9 6DP: not on the flood risk listAL9 6DQ: not on the flood risk listAL9 6DR: not on the flood risk listAL9 6DS: not on the flood risk listAL9 6DU: not on the flood risk listAL9 6DW: not on the flood risk listAL9 6DX: not on the flood risk listAL9 6DZ: not on the flood risk listAL9 6EA: not on the flood risk listAL9 6EB: not on the flood risk listAL9 6EE: not on the flood risk listAL9 6EF: not on the flood risk listAL9 6EG: not on the flood risk listAL9 6EH: not on the flood risk listAL9 6GH: not on the flood risk listAL9 6GJ: not on the flood risk listAL9 6GL: not on the flood risk listAL9 6GZ: not on the flood risk listAL9 6HB: not on the flood risk listAL9 6HD: not on the flood risk listAL9 6HE: not on the flood risk listAL9 6HG: not on the flood risk listAL9 6HH: not on the flood risk listAL9 6HJ: not on the flood risk listAL9 6HL: not on the flood risk listAL9 6HN: not on the flood risk listAL9 6HP: not on the flood risk listAL9 6HQ: not on the flood risk listAL9 6HS: not on the flood risk listAL9 6HT: not on the flood risk listAL9 6HU: not on the flood risk listAL9 6HW: not on the flood risk listAL9 6HY: not on the flood risk listAL9 6JA: not on the flood risk listAL9 6JB: not on the flood risk listAL9 6JD: not on the flood risk listAL9 6JE: not on the flood risk listAL9 6JF: not on the flood risk listAL9 6JG: not on the flood risk listAL9 6JH: not on the flood risk listAL9 6JL: not on the flood risk listAL9 6JN: not on the flood risk listAL9 6JQ: not on the flood risk listAL9 6JR: not on the flood risk listAL9 6JS: not on the flood risk listAL9 6JW: not on the flood risk listAL9 6JY: not on the flood risk listAL9 6LA: not on the flood risk listAL9 6LB: not on the flood risk listAL9 6LZ: not on the flood risk listAL9 6NA: not on the flood risk listAL9 6ND: not on the flood risk listAL9 6NE: not on the flood risk listAL9 6NF: not on the flood risk listAL9 6NG: not on the flood risk listAL9 6NH: not on the flood risk listAL9 6NJ: not on the flood risk listAL9 6NL: not on the flood risk listAL9 6NN: not on the flood risk listAL9 6NP: not on the flood risk listAL9 6NQ: not on the flood risk listAL9 6NR: not on the flood risk listAL9 6NS: not on the flood risk listAL9 6NT: not on the flood risk listAL9 6NW: not on the flood risk listAL9 6NX: not on the flood risk listAL9 6NY: not on the flood risk listAL9 6NZ: not on the flood risk listAL9 6PR: not on the flood risk listAL9 6PS: not on the flood risk listAL9 6PT: not on the flood risk listAL9 6WA: not on the flood risk listAL9 7AA: not on the flood risk listAL9 7AB: not on the flood risk listAL9 7AD: not on the flood risk listAL9 7AE: not on the flood risk listAL9 7AF: not on the flood risk listAL9 7AG: not on the flood risk listAL9 7AH: not on the flood risk listAL9 7AJ: not on the flood risk listAL9 7AL: not on the flood risk listAL9 7AN: not on the flood risk listAL9 7AQ: not on the flood risk listAL9 7AT: not on the flood risk listAL9 7AU: not on the flood risk listAL9 7AX: not on the flood risk listAL9 7AY: not on the flood risk listAL9 7AZ: not on the flood risk listAL9 7BA: not on the flood risk listAL9 7BD: not on the flood risk listAL9 7BL: not on the flood risk listAL9 7BN: not on the flood risk listAL9 7BP: not on the flood risk listAL9 7BS: not on the flood risk listAL9 7BT: not on the flood risk listAL9 7BU: not on the flood risk listAL9 7BW: not on the flood risk listAL9 7BX: not on the flood risk listAL9 7BY: not on the flood risk listAL9 7BZ: not on the flood risk listAL9 7DF: not on the flood risk listAL9 7DG: not on the flood risk listAL9 7DH: not on the flood risk listAL9 7DJ: not on the flood risk listAL9 7DL: not on the flood risk listAL9 7DN: not on the flood risk listAL9 7DQ: not on the flood risk listAL9 7DR: not on the flood risk listAL9 7DW: not on the flood risk listAL9 7DY: not on the flood risk listAL9 7DZ: not on the flood risk listAL9 7EA: not on the flood risk listAL9 7ED: not on the flood risk listAL9 7EE: not on the flood risk listAL9 7EF: not on the flood risk listAL9 7EG: not on the flood risk listAL9 7EL: not on the flood risk listAL9 7EN: not on the flood risk listAL9 7ES: not on the flood risk listAL9 7EU: not on the flood risk listAL9 7EW: not on the flood risk listAL9 7EX: not on the flood risk listAL9 7FA: not on the flood risk listAL9 7HB: not on the flood risk listAL9 7HF: not on the flood risk listAL9 7HJ: not on the flood risk listAL9 7HR: not on the flood risk listAL9 7HT: not on the flood risk listAL9 7HX: not on the flood risk listAL9 7HZ: not on the flood risk listAL9 7JA: not on the flood risk listAL9 7JB: not on the flood risk listAL9 7JE: not on the flood risk listAL9 7JL: not on the flood risk listAL9 7LA: not on the flood risk listAL9 7LD: not on the flood risk listAL9 7LE: not on the flood risk listAL9 7LF: not on the flood risk listAL9 7LG: not on the flood risk listAL9 7LH: not on the flood risk listAL9 7LJ: not on the flood risk listAL9 7LL: not on the flood risk listAL9 7LP: not on the flood risk listAL9 7LQ: not on the flood risk listAL9 7LR: not on the flood risk listAL9 7LS: not on the flood risk listAL9 7LT: not on the flood risk listAL9 7LW: not on the flood risk listAL9 7LY: not on the flood risk listAL9 7LZ: not on the flood risk listAL9 7NA: not on the flood risk listAL9 7NB: not on the flood risk listAL9 7ND: not on the flood risk listAL9 7NE: not on the flood risk listAL9 7NF: not on the flood risk listAL9 7NG: not on the flood risk listAL9 7NH: not on the flood risk listAL9 7NJ: not on the flood risk listAL9 7NL: not on the flood risk listAL9 7NN: not on the flood risk listAL9 7NP: not on the flood risk listAL9 7NR: not on the flood risk listAL9 7NS: not on the flood risk listAL9 7NT: not on the flood risk listAL9 7NU: not on the flood risk listAL9 7NW: not on the flood risk listAL9 7NX: not on the flood risk listAL9 7NY: not on the flood risk listAL9 7NZ: not on the flood risk listAL9 7PA: not on the flood risk listAL9 7PB: not on the flood risk listAL9 7PD: not on the flood risk listAL9 7PE: not on the flood risk listAL9 7PG: not on the flood risk listAL9 7PH: not on the flood risk listAL9 7PJ: not on the flood risk listAL9 7PL: not on the flood risk listAL9 7PN: not on the flood risk listAL9 7PP: not on the flood risk listAL9 7PS: not on the flood risk listAL9 7PT: not on the flood risk listAL9 7PU: not on the flood risk listAL9 7PW: not on the flood risk listAL9 7PX: not on the flood risk listAL9 7PY: not on the flood risk listAL9 7PZ: not on the flood risk listAL9 7QG: not on the flood risk listAL9 7QH: not on the flood risk listAL9 7QJ: not on the flood risk listAL9 7QN: not on the flood risk listAL9 7QQ: not on the flood risk listAL9 7QR: not on the flood risk listAL9 7QS: not on the flood risk listAL9 7QT: not on the flood risk listAL9 7QW: not on the flood risk listAL9 7QX: not on the flood risk listAL9 7QY: not on the flood risk listAL9 7QZ: not on the flood risk listAL9 7RL: not on the flood risk listAL9 7RP: not on the flood risk listAL9 7RR: not on the flood risk listAL9 7RS: not on the flood risk listAL9 7RT: not on the flood risk listAL9 7RU: not on the flood risk listAL9 7RW: not on the flood risk listAL9 7RX: not on the flood risk listAL9 7RY: not on the flood risk listAL9 7RZ: not on the flood risk listAL9 7SA: not on the flood risk listAL9 7SB: not on the flood risk listAL9 7SE: not on the flood risk listAL9 7SL: not on the flood risk listAL9 7SN: not on the flood risk listAL9 7SS: not on the flood risk listAL9 7SU: not on the flood risk listAL9 7SZ: not on the flood risk listAL9 7TA: not on the flood risk listAL9 7TB: not on the flood risk listAL9 7TE: not on the flood risk listAL9 7TF: not on the flood risk listAL9 7TH: not on the flood risk listAL9 7TJ: not on the flood risk listAL9 7TL: not on the flood risk listAL9 7TN: not on the flood risk listAL9 7TP: not on the flood risk listAL9 7UG: not on the flood risk listAL9 7UH: not on the flood risk listAL9 7UJ: not on the flood risk listAL9 7UL: not on the flood risk listAL9 7UP: not on the flood risk listAL9 7UQ: not on the flood risk listAL9 7UR: not on the flood risk listAL9 7UT: not on the flood risk listAL9 7UU: not on the flood risk listAL9 7UW: not on the flood risk listAL9 7UX: not on the flood risk listAL9 7YZ: not on the flood risk listAL9 7TY: very low flood risk onlyAL9 5NY: low flood risk at worstAL9 5RG: low flood risk at worstAL9 7SW: low flood risk at worstAL9 7TX: low flood risk at worstAL9 7UN: low flood risk at worstAL9 6JJ: medium flood risk at worstAL9 7TG: medium flood risk at worstAL9 7TR: medium flood risk at worstAL9 7TT: medium flood risk at worstAL9 7TU: medium flood risk at worstAL9 7TW: medium flood risk at worstAL9 5LZ: high flood riskAL9 5NT: high flood riskAL9 5PB: high flood riskAL9 5PG: high flood riskAL9 5PJ: high flood riskAL9 6AA: high flood riskAL9 6AD: high flood riskAL9 6AX: high flood riskAL9 6AZ: high flood riskAL9 7BB: high flood riskAL9 7PF: high flood riskAL9 7SX: high flood riskAL9 7TD: high flood riskAL9 7TS: high flood risk Brookmans ParkHatfieldWelham Green Map of every postcode in AL9, by flood risk Of the 429 postcodes in AL9 that ONS places, 15 have a home or business at high risk, 6 are at medium risk at worst, 5 are at low risk at worst, 1 are at very low risk only and 402 are not on the Environment Agency's at-risk list. Places named: Brookmans Park, Hatfield, Welham Green. Drawn over roads, rivers and built-up areas. North is up; the scale bar is 1 km. A414 Brookmans ParkHatfieldWelham Green
  • A home or business at high risk: 15
  • At medium risk at worst: 6
  • At low risk at worst: 5
  • At very low risk only: 1
  • Not on the at-risk list: 402

Of the 429 postcodes in AL9 that ONS places, 15 have a home or business at high risk, 6 are at medium risk at worst, 5 are at low risk at worst, 1 are at very low risk only and 402 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.

The middle of its postcodes: latitude 51.7443, longitude -0.1974. Open this area on OpenStreetMap

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

15 postcodes here have a home or business at high risk. These are the 12 with the most homes and businesses at that risk.

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

AL9 7BB12 at high riskAL9 5NT4 at high riskAL9 6AD4 at high riskAL9 7PF3 at high riskAL9 5PD2 at high riskAL9 7TS1 at high riskAL9 5LZ1 at high riskAL9 5PB1 at high riskAL9 5PG1 at high riskAL9 5PJ1 at high riskAL9 6AA1 at high riskAL9 6AX1 at high risk

What broadband can you get in AL9?

Ofcom reports on 426 of the 429 postcodes in AL9. At 214 of them every home and business can get gigabit broadband, and at 1 some cannot get decent broadband (10 Mbit/s).

Postcodes where every home can get gigabit214 of 426
Postcodes where every home can get superfast342 of 426
Postcodes where some cannot get decent broadband1 of 426

Ofcom gives each postcode's share of homes and businesses, not how many there are, so these count postcodes. Each postcode page has its own figures. A provider's checker answers for one address.

Check one address on Ofcom's checker

Source: Ofcom, Connected Nations, Spring 2026, data for January 2026, Open Government Licence v3.0. How we use it

Is AL9 at risk of flooding?

27 of the 429 postcodes in AL9 have a home or business in an area at risk of flooding from rivers or the sea, the Environment Agency says. At those, it puts 53 homes and businesses in an area at high or medium risk.

Homes and businesses in an area at risk, at 27 of 429 postcodes High: 35Medium: 18Low: 52Very low: 21

High: 3.3% or more a year (1 in 30). Medium: 1% to 3.3% a year. Low: 0.1% to 1% a year. Very low: under 0.1% a year (1 in 1,000). Each band is the chance of flooding in any one year.

Homes and businesses in an area at risk of flooding from rivers or the sea, as the Environment Agency counts them, added up over the postcodes. It is for the land, not each building, and leaves out surface water, groundwater and sewers. Each postcode page has its own figures and its flood warning areas.

Source: Environment Agency, Risk of Flooding from Rivers and Sea (postcodes in areas at risk), published 6 July 2026, Open Government Licence v3.0. How we use it

What do homes sell for in AL9?

Homes in AL9 sold for a typical £580,000 in the 12 months to August 2026, across 104 sales, up 0.9% on the 12 months before, HM Land Registry's figures show.

£580,000 typical price, the 12 months to August 2026
12 months to August 2025
£575,000
12 months to August 2026
£580,000

▲ up 0.9% on the 12 months before

Detached£1,002,500 24 sales
Semi-detached£612,500 34 sales
Terraced£490,000 27 sales
Flat or maisonette£250,000 19 sales

Standard sales of homes at market value. A typical price is the median, the middle sale. Sales take weeks to be registered, so the last month or two are incomplete. Each postcode page gives the figure for its own postcode sector.

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 AL9

Pick a sector, then a postcode. A sector is the district plus the next digit.

AL9 5127 postcodesAL9 6112 postcodesAL9 7190 postcodes
UK postcode format explained

Places in AL9

Towns and villages with postcodes in AL9, and how many each has here.

Brookmans Park postcodes,99Hatfield postcodes,94Welham Green postcodes,92

Who covers AL9

How many of the district's postcodes in use fall under each council, constituency and police force area.

Councils

What council am I in?

Constituencies

  • Welwyn Hatfield427
  • North East Hertfordshire2

Police force areas

  • Hertfordshire429

Next to AL9

AL8 postcode district AL10 postcode district All AL districts Brookmans Park postcodes

"Next to" is by number: the districts before and after AL9 in the AL area.

Check a postcode

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