Guides · API

Flood risk API for Dutch addresses

Netherlands flood risk (overstromingsrisico) per address from Rijkswaterstaat LIWO: annual probability that the location floods (any water, over 20, 50 and 200 cm), 2050 and 2100 climate scenarios, worst-case modelled water depth, and ground height vs sea level (AHN). Climate and physical risk data for real estate, mortgage, insurance, ESG and relocation agents. Input: postcode + house number.

0.004 USDC per call · GET /v1/flood-risk · free preview at /v1/flood-risk/preview

Parameters

Name	Required	Description
`postcode`	no	Dutch postcode, 4 digits + 2 letters, e.g. 3511LX
`house_number`	no	House number, e.g. 1
`house_letter`	no	Optional house letter, e.g. A
`addition`	no	Optional house number addition, e.g. 2 or BIS
`q`	no	Alternative to postcode: free-text address, e.g. 'Visschersplein 1 Utrecht'

Example request

curl "https://factline.dev/v1/flood-risk?postcode=2517AS&house_number=100"
# 402 Payment Required: pay with an x402 client (USDC on Base), or send
# Authorization: Bearer <your Factline API key>

Example response

{
  "address": {
    "label": "Laan van Meerdervoort 100, 2517AS 's-Gravenhage",
    "postcode": "2517AS",
    "house_number": 100,
    "city": "'s-Gravenhage",
    "lat": 52.08359668,
    "lon": 4.29193161
  },
  "summary": "Chance of flooding deeper than 50 cm: less than 1 in 30,000 per year (extremely small). Worst modelled water depth: 1.44 m.",
  "ground_height": {
    "metres_nap": 1.44,
    "below_sea_level": false
  },
  "flood_probability_today": {
    "any_water": {
      "class": 1,
      "label": "extremely small",
      "annual": "less than 1 in 30,000 per year"
    },
    "over_20_cm": {
      "class": 1,
      "label": "extremely small",
      "annual": "less than 1 in 30,000 per year"
    },
    "over_50_cm": {
      "class": 1,
      "label": "extremely small",
      "annual": "less than 1 in 30,000 per year"
    },
    "over_200_cm": {
      "class": 0,
      "label": "not exposed",
      "annual": "none modelled"
    }
  },
  "flood_probability_over_50_cm_future": {
    "2050": {
      "class": 2,
      "label": "very small",
      "annual": "1 in 3,000 to 1 in 30,000 per year"
    },
    "2100": {
      "class": 2,
      "label": "very small",
      "annual": "1 in 3,000 to 1 in 30,000 per year"
    }
  },
  "worst_case_max_water_depth_m": 1.44,
  "source": "Rijkswaterstaat LIWO (basisinformatie-overstromingen.nl), AHN via PDOK"
}

Use it from an AI agent

Agents with an x402 wallet call the URL directly and pay per request. Assistants that speak MCP connect to https://factline.dev/mcp. Full reference: docs, OpenAPI, llms.txt. Businesses: API keys with a free trial.

Questions

How much does the Flood risk API for Dutch addresses cost?

0.004 USDC per call, paid per request with x402 (no account), or included in a Factline API key plan with a free trial. Calls that fail are not charged.

Can I try it for free?

Yes: GET /v1/flood-risk/preview with the same parameters validates your input and shows what the paid answer contains, at no cost.

Where does the data come from?

Official public registers and open data, named with their licence in every response (source field) and at /.well-known/x402-license-provenance.