> ## Documentation Index > Fetch the complete documentation index at: https://docs.ariscomfort.com/llms.txt > Use this file to discover all available pages before exploring further. # Get DHW tank status > Returns current domestic hot water tank status including temperatures, state of charge, and effective capacity. ## OpenAPI ````yaml get /api/dhw openapi: 3.1.0 info: title: Aris API version: 1.0.0 description: > REST API for controlling Aris home comfort systems. Aris is an air-to-water heat pump system that heats, cools, and provides hot water for homes. The Aris Brain is the central controller, managing zones, fan-coil units (FCUs), heat pumps, domestic hot water (DHW), and thermal energy storage (TES). ## Base URL The Aris Brain runs on your local network. Find your Brain's address via: - mDNS: `http://aris.local` (if your network supports mDNS) - Router admin panel: Look for a device named "aris-brain" ## Authentication Most API endpoints require authentication via Bearer token. Create an API token in the Aris web UI under **Settings → API Tokens**. Include the token in the `Authorization` header: ``` Authorization: Bearer your-api-token ``` ## Real-time Updates For real-time updates, connect to the WebSocket at `ws://aris.local?token=YOUR_API_TOKEN`. The WebSocket broadcasts zone state changes, system events, and device telemetry. servers: - url: http://aris.local description: Local network (mDNS) - url: http://{brainIp} description: Local network (IP address) variables: brainIp: default: 192.168.1.100 description: Your Aris Brain's IP address security: [] tags: - name: Health description: Health check and readiness endpoints - name: System description: System-wide state and mode control - name: Zones description: Zone management, setpoints, and temperature control - name: DHW description: Domestic Hot Water tank status and history - name: TES description: Thermal Energy Storage tank status - name: HCU description: Hydronic Control Unit status - name: Heat Pumps description: Heat pump telemetry and diagnostics - name: FCUs description: Fan Coil Unit telemetry and status - name: Weather description: Weather data and forecasts - name: Events description: System event log and audit trail - name: Metrics description: VictoriaMetrics time-series data proxy - name: Prometheus description: Prometheus-compatible API for Grafana - name: Tokens description: API token management - name: Config description: System configuration (read-only) - name: Firmware description: FCU firmware OTA updates paths: /api/dhw: get: tags: - DHW summary: Get DHW tank status description: >- Returns current domestic hot water tank status including temperatures, state of charge, and effective capacity. operationId: getDHWStatus responses: '200': description: DHW tank status content: application/json: schema: $ref: '#/components/schemas/DHWStatus' '401': $ref: '#/components/responses/Unauthorized' '503': description: DHW service not available content: application/json: schema: $ref: '#/components/schemas/Error' security: - bearerAuth: [] components: schemas: DHWStatus: type: object description: > Domestic hot water tank status. The DHW tank stores potable hot water and acts as part of the Aris thermal-storage strategy. A mixing valve ensures delivered water temperature remains stable and scald-safe, independent of internal tank temperature. required: - dhwId - tempTopC - tempBottomC - heatingActive - recircEnabled properties: dhwId: type: string description: Unique identifier for the DHW tank example: dhw_main tempTopC: type: number description: > Temperature at the top of the tank (Celsius). Primary indicator of available hot water since hot water is drawn from the top. example: 51.2 tempBottomC: type: number description: > Temperature at the bottom of the tank (Celsius). Indicates remaining cold mass and total usable energy. Cold water enters at the bottom during draws. example: 45.1 tempMidC: type: number description: > Mid-layer temperature (Celsius). Improves stratification accuracy for state of charge calculations. Only present if the tank has a mid-layer sensor installed. example: 48.7 stateOfChargePercent: type: integer minimum: 0 maximum: 100 description: > Calculated energy level (0-100%) based on stratification vs target temperatures. Computed by the Brain from temperature readings. Only present when Brain has sufficient data to calculate. example: 75 effectiveCapacityLiters: type: number description: > Usable hot water capacity (liters) accounting for mixing valve boost effect. Because the mixing valve blends tank water with cold supply, the effective capacity can exceed the physical tank volume. Computed by the Brain. example: 242 heatingActive: type: boolean description: True when the tank is currently being charged by the HCU example: false isSanitizing: type: boolean description: > True during active Legionella sanitization cycle. The tank is heated to an elevated temperature (~65C) to kill bacteria. Normal operation resumes after the cycle completes. example: false dhwDeliveryTempC: type: number description: > Temperature of mixed hot water delivered to fixtures (Celsius), measured after the mixing valve. Primary indicator of user experience and scald protection. Only present if delivery temperature sensor is installed. example: 48.5 dhwColdSupplyTempC: type: number description: > Temperature of incoming cold water supply (Celsius). Used for energy calculations and freeze protection alerts. Only present if cold supply sensor is installed. example: 12.3 backupHeaterActive: type: boolean description: > Whether the electric backup heater (if present) is currently energized. Used for resiliency and extreme-condition recovery when heat pump cannot meet demand. example: false recircEnabled: type: boolean description: True if the home has a DHW recirculation loop installed example: true recircPumpActive: type: boolean description: | True if the recirculation pump is currently running. Only present if recirculation is enabled. example: false lastSanitizationTs: type: string format: date-time description: > ISO 8601 timestamp (UTC) of the last completed Legionella sanitization cycle. Used for maintenance scheduling and compliance reporting. example: '2024-01-15T03:00:00Z' Error: type: object properties: error: type: string description: Error type message: type: string description: Human-readable error message hint: type: string description: Suggestion for resolving the error responses: Unauthorized: description: Missing or invalid authentication content: application/json: schema: type: object properties: error: type: string example: Unauthorized message: type: string example: Valid authentication required securitySchemes: bearerAuth: type: http scheme: bearer description: Session token or API token ````