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Data Sources & Methodology

Complete transparency about where our data comes from and how we maintain accuracy.

Our Core Principle

All property data on NotForSale.ie comes from publicly available sources.

We do not collect private information, conduct surveillance, or trespass on properties. Every piece of data can be independently verified through official public records.

Primary Data Sources

Local Authority Derelict Sites Registers
Official public registers maintained by Ireland's 31 local councils

Under the Derelict Sites Act 1990, local councils maintain public registers of sites deemed derelict. These registers include addresses, property descriptions, and levy information.

What we extract:

  • • Property address and location
  • • Registration date on derelict register
  • • Property type (residential, commercial, mixed)
  • • Council levy status (where publicly disclosed)

Legal basis: Freedom of Information Act 2014, Derelict Sites Act 1990 (public registers)

Community-Submitted Reports
Verified reports from members of the public

Community members submit information about vacant or derelict properties they observe in their neighborhoods. These reports are manually verified before publication.

Verification process:

  • • Cross-reference with Google Street View (if available)
  • • Check against council planning portals
  • • Verify address exists in Eircode database
  • • Require photographic evidence (no identifying personal data)
  • • Admin review before approval

Privacy protection: We do not publish names, phone numbers, or personally identifiable information about property owners

Public Mapping & Location Data
Geospatial data from open sources

Property locations are geocoded using public address data and mapped using open-source mapping services.

Sources used:

  • • Eircode Finder (public address database)
  • • OpenStreetMap (open mapping data)
  • • Google Maps API (geocoding and location services)
  • • OSI (Ordnance Survey Ireland) public datasets
What We Do NOT Collect

To protect privacy and operate ethically, we explicitly DO NOT collect or publish:

  • ✗Property owner names or personal identities
  • ✗Phone numbers, email addresses, or contact details
  • ✗Property interior photos or trespass-obtained information
  • ✗Financial records or property valuations (unless publicly disclosed by councils)
  • ✗Health, family, or demographic information about owners
  • ✗Data obtained through surveillance, deception, or unauthorized access
Data Accuracy & Updates

Update Frequency:

  • • Council register data: Quarterly (every 3 months)
  • • Community reports: Reviewed and verified within 48-72 hours
  • • Property status changes: Updated when verified information becomes available

Accuracy Standards:

We aim for 95%+ accuracy on core property data (address, location, derelict status). Because data comes from multiple sources and property conditions change, some information may be outdated. Users can report inaccuracies to help us maintain quality.

Dispute Resolution:

Property owners or others who believe information is inaccurate can contact us to request review. We will investigate and update or remove information within 5 business days.

GDPR & Data Protection Compliance

NotForSale.ie complies with the EU General Data Protection Regulation (GDPR) and Ireland's Data Protection Act 2018.

Our compliance approach:

  • • Lawful basis: Public task (facilitating community housing initiatives) and legitimate interests
  • • Data minimization: We collect only necessary property-related data, no unnecessary personal information
  • • Purpose limitation: Data used solely for housing advocacy and community information
  • • Accuracy: Regular updates and correction mechanisms
  • • Storage limitation: Data retained as long as properties remain relevant to housing crisis
  • • Integrity & confidentiality: Secure storage with access controls

For details on how we handle user data (not property data), see our Privacy Policy.

Methodology Summary
  1. 1. Source Identification: Identify publicly available data sources (council registers, planning portals, community reports)
  2. 2. Data Collection: Extract property addresses, locations, and derelict status only
  3. 3. Verification: Cross-reference multiple sources and apply admin review for community submissions
  4. 4. Privacy Filtering: Strip all personal identifying information about owners
  5. 5. Publication: Publish verified property data on map and database
  6. 6. Monitoring & Updates: Quarterly updates from official sources, continuous community feedback integration

This methodology is a living document and may be updated to improve accuracy and transparency.

Questions about our data sources? Contact us

Last updated: 2 March 2026