Rent rolls and AI data leakage: what a property management spreadsheet gives away in ChatGPT or Claude.

The rent roll is the working list of a property management department: every property, who lives in it, what they pay, who is behind and who owns it. Property managers keep it in a spreadsheet because the software exports to one, and they upload it to ChatGPT or Claude to total arrears, chase late payers or draft reminders. The sheet puts tenants’ hardship next to owners’ names and bank details, with a notes column that records separations, violence orders and deaths. This page marks what a routine NSW rent roll exposes and shows how the same list is worked on Ermos inside the agency.

The rent roll spreadsheet

Kept by the property manager from the management software and trust account, to chase arrears, plan lease renewals and report to owners. Rent collected for owners is held in trust, which NSW Fair Trading says must be kept separate from sales money and audited each year.

An invented rent roll as at 30 October 2026. All people and streets are fictional and the bank details are placeholders. Hover or tap any highlighted item for the analysis; the full list is below.

What leaves the agency

1. 1
   Property addresses

   The address of every managed home. Together with the tenant it tells anyone reading where a named person sleeps. Privacy Act guide.

2. 2
   Tenant names

   Every occupant of every managed property. Personal information, and the key to every other column. Privacy Act guide.

3. 3
   Weekly rents

   Rent against a named tenant. Advertised rents are public, but a tenant’s own rent is not.

4. 4
   Arrears

   Who is behind and by how much. Financial hardship, the kind of debt NSW tenancy database rules limit listings for, since a tenant can be listed only after the tenancy has ended, and only for a debt over the bond or after a Tribunal termination order. Privacy Act guide.

5. 5
   Lease end dates

   When each tenancy ends. It shows which tenants can be moved on and when, and what an owner may be planning.

6. 6
   Owners

   Named landlords, one an estate. Personal information about the agency’s other clients, who are owed the same care as vendors. Privacy Act guide.

7. 7
   Owner bank details

   The account each owner is paid into. The details payment redirection fraud needs, in a file that also lists when the rent is paid. Privacy Act guide.

8. 8
   The notes column

   Free text with the most sensitive detail: a separation, a violence order, a death, a job loss and an owner’s plan to sell. Health and safety information that the agency has to be able to keep to itself. Privacy Act guide.

9. 9
   The total-arrears formula

   A sum with no personal information in it. The same formula can be shared safely, and the sheet it sits in cannot.

10. 10
    Other tabs, hidden columns and file properties

    A spreadsheet file generally carries more than the visible tab: other sheets, hidden columns, cell comments and properties such as the author. A trust ledger tab would carry the money records the licensee must keep and have audited each year. Uploading the file sends all of it.

What happens in Frontier Models (ChatGPT, Claude)

• The whole document is transmitted to the provider’s servers. On personal plans the user cannot choose where it is stored or processed, and for the major providers that has generally meant outside Australia, under that country’s legal process. Some business plans offer storage in Australia, but the provider still receives the content.
• On consumer tiers, prompts can be retained and used to train future models.
• The provider’s staff and systems can reach the content under the provider’s own policies.
• Once sent, the agency no longer controls it. Retention and deletion happen on the provider’s terms.

The same document on Ermos

Part of AI data leakage in real estate agencies.

Common questions