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Portfolio Screening for Up to 200 Addresses

Portfolio screening checks a list of up to 200 addresses from a CSV file. Each address gets an overall flood band, its flood zone, surface water likelihood, whether it is inside a reservoir flood extent, a crime level, its deprivation decile, sales in its postcode sector and the nearest station. You get a sortable table, a map and a CSV.

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Portfolio screening of the five-address sample file: a summary saying all 5 addresses were located, 2 have a medium or high flood likelihood (2 in flood zone 3, 1 medium or high for surface water), 1 is inside a reservoir flood extent and 4 are in neighbourhoods in England's two highest crime deciles, above a map of England and Wales with each address coloured by its highest flood likelihood.

What You Give It

  • A CSV file with a header row, up to 200 addresses and under 2 MB. Commas, semicolons and tabs all work as separators.
  • In each row, a postcode, a latitude and longitude, or an address with its postcode written in it.
  • A reference column if you have one (named ref, reference, id, policy, account or name, for example). It is kept, so the results join back to your own records.
  • A sample file with five addresses shows the format.

What You Get

  • A Summary of What Is Flagged

    How many rows were located, and how many have a medium or high flood likelihood, are in flood zone 3, are inside a reservoir flood extent or are in a high-crime neighbourhood.

  • A Sortable Table

    One row per address: the overall flood band, the river and sea band, the flood zone, the surface water band, reservoir, crime level and crimes a year, deprivation decile, sector sales and median price, nearest station, and any problem with the row. Show only the flagged addresses with one switch.

  • A Map of the Portfolio

    Every located address, coloured by its highest flood likelihood. Choose a row in the table to find it on the map.

  • A CSV to Download

    The same columns as the table, ready to join back to your records. Text that a spreadsheet could run as a formula is written as plain text.

How It Works

The page reads your file and sends the addresses to be checked a few at a time. Each address is placed by its latitude and longitude when the file gives them, otherwise at its postcode centre from the ONS Postcode Directory.

What Each Address Gets

  • Flood: the flood zone (Environment Agency Flood Map for Planning, which ignores defences), the Environment Agency's likelihood from rivers and the sea with defences, and its likelihood from surface water. The river and sea band follows the same rule as the property risk check: raised to medium in flood zone 3. The overall band is the higher of the river and sea band and the surface water band.
  • Reservoirs: inside the wet-day reservoir flood extent or not.
  • Crime: crimes recorded within 250 m over the latest 3 months, as a yearly rate, and the neighbourhood's crime level from its crime decile in the English Indices of Deprivation 2025. High means deciles 1 and 2.
  • Deprivation: the neighbourhood's decile in the English Indices of Deprivation 2025, from 1 (most deprived) to 10.
  • Sales: the number of standard sales and their median price across the postcode sector, from HM Land Registry sales between 30 September 2024 and 30 September 2026.
  • Station: the straight-line distance to the nearest rail station (NaPTAN).

Rows That Cannot Be Checked

No row is dropped. If a postcode is mistyped, new or retired, the coordinates are outside England and Wales, the row has no postcode or coordinates, or a service did not answer, the row stays in the table with the reason in its problem column.

The public version is a lighter screening than the single-address check: the wet-day reservoir extent only, crime over 3 months, sales for the postcode sector and no ground heights. For the full check on one address, use the property risk check.

The Five-Address Sample File

In an example screening on 9 November 2026 of the sample file (Old Market Square and the Meadows in Nottingham, King's Staith in York, Tower Hill in London and Bristol harbourside), all 5 addresses were located. 2 had a medium or high flood likelihood from rivers, the sea or surface water: both were in flood zone 3, and 1 of them was medium or high for surface water. 1 was inside a reservoir flood extent and 4 were in neighbourhoods in England's two highest crime deciles.

Screen the sample file

The Data Behind It

Every dataset and its credit line is on data sources and licences.

What It Can't Tell You

  • Up to 200 addresses in one file; split a longer list into parts.
  • A postcode is placed at its centre, which can be tens of metres from the building. Give latitude and longitude for exact points.
  • Ground height and slope are not in the public version. Groundwater, sewer flooding and subsidence are not covered at all.
  • Crime is left blank where data.police.uk is missing months for the police force, because an incomplete count gives no fair yearly figure or band.
  • Not an underwriting or credit model: no claims history, building construction, title, tenure or valuation.
  • England only for flood, reservoirs and deprivation; crime, sales and stations also cover Wales.

The tools are in preview: built and tested, not yet signed off as validated. They screen a place from public data and don't replace a survey or professional advice.

Questions

Something else? Ask us.

What does the CSV need?

A header row, then one address per row with a postcode, a latitude and longitude, or an address that includes the postcode. Columns are recognised by common names such as postcode, post_code, latitude, lat, longitude, lon, address and ref. Anything else in the file is ignored.

How many addresses can I screen at once?

Up to 200 rows in one file of under 2 MB. For a longer list, split it into files of 200 and screen each one; the CSVs you download can then be joined on your reference column.

Why does a row show a problem instead of results?

Because it could not be placed or checked: the postcode was not found (mistyped, new or retired), the coordinates are outside England and Wales, the row has no postcode or coordinates, or a data service did not answer. The reason is written in the row, which stays in the table and the download.

How is the overall flood band worked out?

It is the higher of two bands. The river and sea band starts from the Environment Agency's likelihood with defences and is raised to medium in flood zone 3; the surface water band is the Environment Agency's likelihood at the point.

Is it the same as the single-address risk check?

It uses the same flood rule but is lighter, so a list of addresses can be screened in one go: the wet-day reservoir extent only, crime over the latest 3 months, sales for the postcode sector and no ground heights. Run the property risk check on any address the screening flags.

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