Rainwater Card for Home Assistant

A single-reservoir dashboard card for total stored rainwater, usable reserve, remaining capacity, daily change, and volume history.

Features

• One required total-volume entity
• Capacity-derived fill percentage and visual tank level
• Configurable protected reserve
• Available water and remaining headroom
• 24-hour volume change
• Home Assistant history over 1–30 days
• Native Home Assistant visual configuration
• Responsive light and dark themes
• HACS-compatible packaging

Configuration

type: custom:rainwater-card
title: Rainwater
entity: sensor.watertankhub_total_water_volume_l
capacity: 48000
reserve: 5000
history_days: 7
show_history: true

Only entity is required. capacity and reserve are numeric values in litres, not additional entities.

Development

npm install
npm run dev

Run all tests and build the production bundle:

npm run check

The bundle is emitted to dist/rainwater-card.js.

Manual installation

1. Copy dist/rainwater-card.js to <config>/www/rainwater-card.js.
2. Add /local/rainwater-card.js as a JavaScript module dashboard resource.
3. Add Rainwater Card from Home Assistant's card picker.

Supported volume units

The total-volume sensor may report L, kL, m³, US gallons, or imperial gallons. Values are normalized internally to litres.

License

MIT