Privacy Policy
Last updated: March 21, 2026
What We Collect
When you use ADU Checker, we collect the following information to provide our service:
- Property addresses and coordinates you search for, to perform eligibility analysis.
- Device information including IP address, browser type, and device type, collected automatically with each request.
- Search activity including addresses searched, results returned, and analysis performed.
- Marketing attribution including UTM parameters, referrer URL, and landing page, to understand how you found us.
- Session analytics including page views and feature usage — collected only if you accept analytics cookies.
How We Use Your Data
- To perform ADU eligibility analysis for the addresses you search.
- To understand how people find and use our service.
- To improve our service and fix errors.
Cookies and Tracking
We use cookies and similar technologies as follows:
- Analytics cookies (optional): Google Analytics 4 sets
_ga and _ga_* cookies (up to 2 years) to help us understand site usage and improve the service. These are only placed if you accept analytics cookies via our consent banner. - Functionality: Mapbox sets cookies necessary for map rendering and interaction.
You can change your cookie preferences at any time by clicking “Cookie Settings” in the footer, or by clearing your browser cookies.
Third-Party Services
To provide analysis and operate our service, we use the following third-party services:
- Supabase — data storage (lead tracking, search events)
- Vercel — hosting and deployment
- Google Analytics — website analytics and usage patterns (only with your consent)
- Mapbox — maps and geocoding; collects anonymous map usage data per their privacy policy
- Sentry — error monitoring; collects error diagnostic data including browser type, page URLs, and error details per their privacy policy
We also query public data sources on your behalf:
- City of Chicago Open Data Portal (Socrata) and ArcGIS services
- Cook County Assessor and GIS
- FEMA National Flood Hazard Layer
- NREL (solar potential)
- U.S. EIA (utility rates)
- HUD (fair market rents)
- U.S. Census Bureau ACS (median rent estimates)
- OpenStreetMap (amenities)
These services receive only the minimum data necessary to function.
Data Retention
- Search data: Retained for service operation and analytics. IP addresses are stored in hashed form in exports.
- Analytics events: Retained by Google Analytics per their retention policies (default 14 months). First-party analytics events are retained for service improvement.
We Do Not Sell Your Personal Information
ADU Checker does not sell, rent, or trade your personal information to third parties for monetary or other valuable consideration. We have not sold personal information in the last 12 months and do not plan to do so.
Internal Access and Security
Our team may access aggregated and anonymized data for service improvement, including usage patterns, search trends, and error diagnostics. We implement standard security measures to protect your data, including encrypted connections (HTTPS) and hashed IP addresses in exports.
Your Rights
You may:
- Opt out of analytics cookies via the cookie consent banner.
- Request information about the data we hold about you.
California residents have additional rights under the CCPA, including the right to know what personal information is collected, the right to request its deletion, and the right to opt out of the sale of personal information (which we do not engage in).