Project: Hydrawise or OpenSprinkler in Home Assistant, with a rain skip

Smart sprinkler controllers, soil and rain sensors, and automated watering.
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ZerOne
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Goal
See your irrigation zones in Home Assistant, and skip a watering cycle when it is already raining or has just rained. Official Hunter Hydrawise documentation even lists "skip watering when it rains" as an example automation, which is the path used below. An OpenSprinkler variant is outlined second, with the limitation that Home Assistant support is community software.

Complexity
Moderate. You should already have a working controller and valves. Do not start this project by rewiring a valve box as a first home-automation job.

1. Hydrawise — official integration
  • Create or sign in to the Hydrawise account at app.hydrawise.com.
  • In Account Details, generate an API key.
  • In Home Assistant: Settings, Devices & services, Add Integration, Hunter Hydrawise, and enter the account credentials and API key as the official docs describe.
  • Confirm controllers and zones appear. Official supported families include Pro-HC, HPC, HCC, X2 with WAND, and HC. Rain sensors and flow meters attached to the controller should appear if they are fitted.
Known official limitations to expect: "Invalid authentication" if the API key is wrong; entities unavailable if the controller is offline; zone start/stop can take a few minutes to show in Home Assistant.

2. Official idea: skip watering when it rains
The Hydrawise integration can pause the automatic watering schedule. Official docs describe seeing when zones water, starting and stopping zones, and pausing the schedule, and they give "skip watering when it rains" as the example.

A cautious pattern:
  • Use the controller's own rain sensor if you have one (preferred, because it sits at the garden).
  • Or use a reliable local weather / rain sensor already in Home Assistant.
  • When rain is detected, pause the Hydrawise schedule or skip the next run, then resume after the sensor clears plus a margin (many people use the next morning).
Keep the pause on the controller schedule, not only as a Home Assistant "don't start" condition, so a missed automation does not leave the official program running in a storm. Test this on a single zone first, in daylight, while you can see the sprinklers.

3. OpenSprinkler — local controller, community Home Assistant path
OpenSprinkler runs its own firmware and API on the controller. At the time of writing there is no official core Home Assistant integration. If you use a community integration (often installed through HACS), record the exact project and version you used, and test a rain skip the same way: prefer pausing or rain-delaying on the controller. Do not depend on a cloud account to stop a valve.

4. A simple fail-safe
  • If Home Assistant restarts, the controller should still enforce any rain delay you set on the device.
  • If a flow meter reports unexpected flow when all zones are off, notify you; do not ignore a possible burst pipe.
  • Respect local watering restrictions — an automation is not permission to water on a banned day.
Hardware cost
If the controller is already installed, this is mostly configuration. A new rain sensor or flow meter should be quoted in AUD for your controller model.

Official reading
Hydrawise integration (includes the rain-skip example)
OpenSprinkler

Researched from official documentation on 15 November 2026 (Australia/Sydney). This is a planning and how-to guide, not a claim that the exact hardware combination was assembled and tested on a live site. Please correct anything that has moved on.
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