Screening tool for whether a residential lot sends water toward the house, and what to do first.
- Homeowner (about 5 minutes): enter an address or open the West Chester demo lot.
- Inspector: IRC R401.3 10-foot envelope, storm context, printable dossier.
- Decision sim: water path, ponding, mitigation toggles.
Not a stamped hydrologic model, FEMA determination, or 1-meter LiDAR survey.
- Address: OpenStreetMap Nominatim, with a SE Pennsylvania fallback.
- Elevation: USGS EPQS centroid plus a regional slope model. Demo lot is a canned failing Piedmont hillside.
- Storms: NOAA Atlas 14 Volume 2 order-of-magnitude 24-hour depths for SE PA, plus a labeled Hurricane Ida regional illustration.
- IRC: 2021 Section R401.3 (6 inch fall in 10 ft) quoted in the UI.
- Simulator: Canvas 3D screening engine. Pressure uses P = rho g h (0.433 psi per foot). Labeled illustrative.
- Gemini: optional. Core diagnostic works without a key.
- PA Home Improvement Consumer Protection Act (73 P.S. 517) quoted for contracts and deposits. Guided path: Address, Site, Inspect, Simulate, Act.
See package.json scripts: start, dev, build.
- Parcel slope is not USGS 3DEP 1-meter LiDAR.
- Atlas 14 numbers are a lookup table.
- Cost bands are regional screening ranges, not bids.
- Gemini key optional. Camera and gyro are phone-only.
Angular 21 standalone, Tailwind CSS v4, Canvas 2D hydro engine.