AL10 9AY Welwyn Hatfield

Streets

• Mosquito Way, Hatfield: 54 addresses

Council tax

What each band costs in Welwyn Hatfield in 2026-27: Band D £2,452 a year on average, including the police, fire and any county and parish charges.

Homes by band in the neighbourhood around this postcode: most are in band D (40% of about 1,030 homes).

Sources: Valuation Office Agency, Council Tax: stock of properties, homes at 31 March 2026 (counts rounded to the nearest 10; some small counts withheld), for the neighbourhood (census area of about 700 homes) around it, not just this postcode; Ministry of Housing, Communities and Local Government, council tax levels 2026-27. Bands are charged as fixed shares of Band D; the actual bill depends on the parish and on discounts such as the single-person discount. Check a home's own band with the official council tax band checker.

Planning and heritage

• Conservation area: no postcode centre in this postcode is in one.
• Listed buildings within 100 m of this postcode: none.
• Article 4 direction (removing permitted development rights): none recorded, though not every council has published theirs.
• Tree preservation orders: none recorded, though not every council has published theirs.
• Green belt: no.

Brownfield land registered for housing within 1 km (0.6 miles)

• Hatfield - Comet Hotel St Albans Road West: up to 124 homes, permissioned (540 m (0.3 miles))
• Hatfield - 12 Harpsfield Broadway: up to 6 homes, permissioned (560 m (0.3 miles))
• Hatfield - Former Volkswagen Van Centre Comet Way: up to 118 homes, permissioned (580 m (0.4 miles))
• Hatfield - 41-43 Roe Green Lane: up to 14 homes, permissioned (700 m (0.4 miles))

Source: planning.data.gov.uk (Ministry of Housing, Communities and Local Government), compiled from councils and, for listed buildings, Historic England's National Heritage List. Conservation areas, Article 4 directions, tree preservation areas and the green belt are checked at each postcode's centre. Listed buildings and protected trees are counted within 100 m of this postcode. Councils publish Article 4 directions, tree preservation orders and brownfield registers to different standards, and some not yet. Planning applications are not here: there is no national open record of them yet.

Flood risk

Rivers, the sea or surface water: in this postcode, 0 addresses are in areas at high risk, 4 at medium risk and 2 at low risk. Each address counts once, at the higher of its rivers-and-sea and surface-water risk.

Rivers and the sea alone: no home is in an area at risk.

High: 3.3% (1 in 30) or more chance of flooding a year. Medium: 1% to 3.3%. Low: 0.1% to 1%. Very low: under 0.1%. The rivers and sea figures allow for flood defences. Counts cover whole postcodes, which can include other streets.

Flood zone for planning: no postcode centre is in flood zone 2 or 3.

Sources: Environment Agency Flood risk: postcode search tool data (loaded 29 October 2026), Risk of Flooding from Rivers and Sea: postcodes in areas at risk (loaded 29 October 2026) and Flood Map for Planning (loaded 28 October 2026). Flood zones are checked at each postcode's centre point. These are models of areas, which their publishers say are not suitable for showing whether an individual property is at risk, and they do not cover flooding from sewers or drains. Check an address on the official long-term flood risk service.

© Environment Agency copyright and/or database right 2026. All rights reserved. Some features are based on digital spatial data from the Centre for Ecology & Hydrology, © NERC (CEH); the postcode data is produced in part from PAF® and Multiple Residence Data, © Royal Mail Group Limited.

Height above sea level

The postcode's addresses are about 75 m above sea level.

Source: Ordnance Survey, OS Terrain 50, July 2026: the height of the ground on a 50 m grid, read at each address, in metres above Ordnance Datum (mean sea level at Newlyn). It is the lie of the land, not floor or threshold levels, and is accurate to a few metres. Being low-lying is not in itself a flood risk; the flood section above says what the flood maps show.

Broadband

Superfast 100%, ultrafast 100%, gigabit 100% of premises; 0% cannot get 10 Mbit/s. Ofcom Connected Nations, data as at January 2026.

Getting around

Sources: Department for Transport, NaPTAN (every public transport stop), as at 31 October 2026; Office of Rail and Road, Estimates of station usage 2024–25 (which stations are on the National Rail network, and their journeys: entries and exits in the year to March); OurAirports (public domain, kept by volunteers); car parks and charging points from Overture Maps Foundation, release 2026-10-21.0, which gathers business listings from Meta, Microsoft, Foursquare and others: not an official register, so some will be missing, private or out of date. Distances are straight lines from the postcode's centre, not routes, and say nothing about how often anything runs. Stations opened since the end of ORR's year appear when ORR publishes the next one, each December; heritage railways are left out.

Local services

Sources: NHS Organisation Data Service, as at 31 October 2026: GP practices, community pharmacies and dental practices with an NHS contract, open now, each placed at the centre of its postcode; hospitals are NHS trust and Welsh health board sites named as hospitals, and may not have an emergency department. Police stations and cash machines from Overture Maps Foundation, release 2026-10-21.0, which gathers business listings: not an official register, so some will be missing or out of date. Distances are straight lines from the postcode's centre. Nothing here says whether a practice is taking new patients or a dentist new NHS patients.

Parks and green space

Source: Ordnance Survey, OS Open Greenspace, April 2026: public parks and gardens, play spaces, playing fields and allotments, with their entrances. Distances are straight lines from the postcode's centre to a site's nearest entrance (or its edge where none is recorded), not walking routes; sizes are the area OS maps for each site. Some sites, such as school playing fields, may not be open to the public.

Within 800 m (0.5 miles): 6 parks and gardens, 82 hectares in all.

Landmarks

The nearest historic landmark is The Flight Test Hangar, Offices, Fire Station and Control Tower, British Aerospace, a listed building (Grade II*), 220 m east. 6 listed buildings are within 1 km (0.6 miles), 1 of them Grade II*.

Sources: Historic England's registers through planning.data.gov.uk (MHCLG), and Cadw through DataMapWales (Welsh Government): World Heritage Sites within 10 km (6.2 miles), battlefields within 5 km (3.1 miles), registered parks and gardens within 3 km (1.9 miles), scheduled monuments within 2 km (1.2 miles), and Grade I and II* listed buildings within 1 km (0.6 miles). Ordnance Survey, OS Open Names, October 2026: named hills, valleys, lakes, woods, wetlands and coast (it has no rivers). Distances are in a straight line to the middle of each site, and being on a register does not mean there is public access.

Air quality

Source: Defra, modelled background air pollution, annual means for 2024, for the 1 km square that holds the postcode's centre. These are background levels, away from the kerb: beside a busy road nitrogen dioxide in particular can be several times higher. UK limits are the legal annual limits for England and Wales; the World Health Organization's 2021 guidelines are much stricter, and most towns and cities are above them.

All three are within the UK legal limits; nitrogen dioxide and PM2.5 are above the WHO guideline, as in most towns and cities.

Road and rail noise

Source: Defra, strategic noise mapping Round 4 (England), modelled for 2021 and published in December 2023, and its airport maps of the same round for the fifteen largest English airports, published in April 2026: Lden, the average sound level over a whole day with extra weight for the evening and night, on a 10 m grid, read at each address. These are models of traffic, not measurements; they leave out smaller airports and airfields, industry and neighbours, and a room at the back of a house is often much quieter than the front. The World Health Organization's guidelines are 53 dB for road traffic, 54 dB for railways and 45 dB for aircraft (below the lowest level shown here).

6 of the postcode's 54 addresses are modelled at 55 dB or more from road traffic, above the WHO guidelines.

Climate, daylight and earthquakes

Monthly temperatures and rainfall, sunrise and sunset through the year, and earthquakes recorded nearby since 1970 are much the same across the area, so they are worked out once for Welwyn Hatfield: see them on the Welwyn Hatfield page.

People and work

Source: ONS Census 2021, taken on 21 March 2021, for the Output Area (a small census area of about 125 households) that this postcode is in: 342 residents in 108 households. The census was taken during a lockdown, so working from home is high and travel to work low compared with now. ONS swaps a few records between neighbouring areas and adds small amounts of noise to counts to protect privacy, so small differences mean little. Industry is not published for areas this small.

Who lives here

Homes

Work and commuting

Education and languages

Deprivation

The neighbourhood around this postcode is in decile 7 of 10 on the English Indices of Deprivation 2025, where 1 is the most deprived tenth of England's 33,755 neighbourhoods and 10 the least.

Source: English Indices of Deprivation 2025 (Ministry of Housing, Communities and Local Government), by LSOA (about 1,500 people), through the ONS Postcode Directory. The index combines income, employment, health, education, crime, housing and living environment; it ranks areas against each other and does not describe any one household. Ranks in England and Wales are worked out separately and cannot be compared.