- Crop profiles built in
- 29
- Weather refresh
- Hourly
- Irrigation outlook
- 7 days
- Prescription precision
- To the mm
See Your Whole Operation at Water Level
Three surfaces, one answer: where to send water, when, and how much
Farm map
Your fields, drawn once, ranked at a glance
- ✓Trace corners or drop a resizable pivot circle, then reshape it anytime. Try both on the demo map
- ✓Switchable heat layers shade every field by water status, deficit, or days to refill
- ✓Mapped acreage feeds volume math automatically
Soil water status
Demo data on real USGS imagery. Every field here is live: tap one to rename, re-crop, reshape, or remove it.
7-day outlook
Watch each field drift toward its refill point
- ✓Each line is one field's root-zone water, day by day. Fields you draw on the map join live
- ✓The refill line marks the moment stress begins
- ✓Scrub the week or tap a field to see exactly when it comes due
7-Day Water Outlook
Every field on the map, including any you draw up there, if no one irrigates. Scrub a day, tap a field to isolate it.
Saturday: no rain forecast. Tap a field above to follow one line.
Morning digest
The day's watering plan, before you reach the truck
- ✓Every field's status and exact amount, in one email
- ✓Amounts grossed for drip, sprinkler, pivot, furrow, or flood
- ✓Daily or weekly, your choice, straight to your inbox
Not a Guess. A Calculation.
Every recommendation is auditable arithmetic from weather physics to pipe: the FAO-56 method agricultural institutions use, run for your fields every hour
1. Live weather
Hourly forecasts and recent conditions for each farm's exact location from Open-Meteo, including Penman-Monteith reference evapotranspiration. No station to buy, no gauge to empty.
2. Crop water use
Your crop's FAO-56 coefficient, adjusted for its growth stage since planting, converts reference ET into what the plant actually drinks today. 29 crops built in.
3. Root-zone balance
A daily checkbook for the soil: effective rain and logged irrigation in, crop water use out, bounded by what your soil texture can hold in the root zone.
4. Prescription
When depletion reaches the refill point, RainRule prescribes the exact depth to refill the root zone, divided by your system's application efficiency.
Equipment automation
From Prescription to Pump
Connect the controllers you already run and RainRule carries out its own schedule. No new hardware, no rip and replace, and you decide how much control to hand over, one field at a time. Built for the operations sensor platforms skip: market gardens, nurseries, hoop houses, and drip orchards on the controllers they already own
Start with recommendations
From day one RainRule prescribes when and how much, and your crew runs the valves like always. Nothing is connected until you decide it should be.
Graduate to review mode
Connect a controller and RainRule proposes each run with the exact depth and minutes, then emails you. One click approves or cancels. Nothing waters without your yes.
Go auto where you trust it
Field by field, let the plan run itself: runs queue inside your watering window and dispatch on schedule. Flip any field back to review whenever you like.
Guardrails a farm can trust
Automation that touches real water has to be paranoid. Every run RainRule dispatches is bounded, confirmed, and logged.
- ✓Watering windows, max runtime caps, and rain-skip thresholds bound every run
- ✓The planner stands down when rain is forecast, the water balance is stale, or the controller is unreachable
- ✓A start command that times out is never retried. RainRule marks the run failed and emails you, because a blind retry could water a field twice
- ✓Completed runs are logged to the field's water balance automatically, so tomorrow's prescription accounts for today's water
- ✓Stop water from the dashboard at any moment
- ✓Controller credentials are sealed with AES-256-GCM, and webhook commands are signed and timestamped
Works with
Rachio
Cloud API connection with zone discovery
Hunter Hydrawise
Cloud API connection with zone discovery
OpenSprinkler
Talks directly to the controller
Custom webhook
Pump relays, PLC bridges, and other hardware behind one signed endpoint
Zones are discovered from the controller and mapped to your fields in one screen
Equipment data API
Plays Well With Probes, Tractors, and GIS
Automation drives your controllers; the data API covers everything else. A documented REST API brings sensor readings into the same water balance your crew already reads, and exports your boundaries to the tools your agronomist uses.
- ✓Scoped API keys you can revoke per integration
- ✓Soil moisture, rainfall, flow, and temperature ingest
- ✓Boundary export as GeoJSON or ISOXML (ISO 11783-10)
- ✓OpenAPI spec included for code generation
curl -X POST \
https://rainrule.com/api/rainrule/v1/ingest/readings \
-H "Authorization: Bearer rr_live_..." \
-H "Content-Type: application/json" \
-d '{"readings": [{
"field_id": "0d5f...",
"source": "probe-7",
"reading_type": "soil_vwc",
"depth_cm": 30,
"ts": "2026-07-04T05:00:00Z",
"value": 0.24
}]}'
{"received": 1, "inserted": 1, "duplicates": 0}Precision Irrigation Without the Guesswork
Science-backed scheduling and hands-off execution that save water, protect yields, and cut costs
Weather-Driven Scheduling
Automatic ETo calculations from live weather data using the FAO-56 Penman-Monteith equation. Know your daily water demand without leaving your desk.
Soil Water Balance Tracking
Daily tracking of root zone moisture deficit in millimeters. See exactly when to irrigate and how much to apply.
29 Crop Profiles Built In
Pre-loaded FAO-56 crop coefficients for corn, wheat, soybeans, vegetables, fruits, and more. Select your crop and go.
7-Day Irrigation Forecasts
See upcoming weather and plan irrigation events in advance. Avoid water stress before it impacts your yield.
Interactive Farm Map
Draw field boundaries on satellite or street view and see every field color-coded by irrigation urgency, so one glance shows where to send water today.
Charts for Every Field
Water balance history, a 7-day action outlook, cumulative demand vs. supply, and soil sensor trends. Spot problems as curves, not table rows.
Runs Your Existing Controllers
Connect Rachio, Hunter Hydrawise, or OpenSprinkler in minutes, or drive pumps, relays, and PLC bridges through a signed webhook. RainRule discovers zones and maps them to your fields.
Review Mode or Full Auto
Choose per field: approve each proposed run with one click, or let runs queue inside your watering window. Rain-skip thresholds and max runtime caps guard every dispatch.
Closed-Loop Run Logging
Every completed run is logged to the field's water balance automatically, and a failed command emails you immediately. Tomorrow's prescription already knows about today's water.
Open Equipment API
A scoped-key API ingests soil probe readings, and boundaries export as ISOXML (ISO 11783-10) for tractor terminals or GeoJSON for GIS tools.
Multi-Farm, Multi-Field
Manage all your farms and fields from one dashboard. Perfect for operators running multiple sites across a region.
Morning Email Digest
Wake up to a per-field summary: current deficit, days until irrigation, and exactly how much to apply, in your inbox before you're in the truck.
Built on Proven Science
RainRule implements the FAO-56 Penman-Monteith equation, the global standard for estimating crop water requirements, published by the Food and Agriculture Organization of the United Nations. This is the same methodology used by agricultural research institutions and irrigation districts worldwide.
FAO-56
Penman-Monteith reference evapotranspiration
Open-Meteo
Live forecasts from global weather models
Hourly
Automatic refresh of every field's water balance
Simple, Transparent Pricing
One plan with everything included. Start with a 14-day free trial (up to 3 fields, no card required)
Soil sensor platforms
$275 to $1,100
per probe, per year
- Probes to buy, install, and maintain
- Data only where the probes sit
Pivot telemetry plans
$200 to $450
per pivot, per year
- $1,000 or more of hardware per machine
- Covers only the equipped pivots
RainRule
$49/mo flat
every field, one price
- No hardware to buy or install
- Runs the controllers you already own
Sensor and telemetry figures are typical published list prices for those categories, rounded. Already run probes? RainRule charts their readings at no extra cost.
What's Included in Every Plan
- ✓Live weather data, no hardware required
- ✓FAO-56 water balance calculations
- ✓7-day irrigation forecasts
- ✓29 crop profiles with Kc coefficients
- ✓Farm map with boundary drawing & satellite view
- ✓Water balance, outlook & soil sensor charts
- ✓Controller automation: Rachio, Hydrawise, OpenSprinkler & signed webhooks
- ✓Review or auto mode per field, with rain-skip & runtime caps
- ✓Equipment API with GeoJSON & ISOXML export
- ✓Multi-farm & multi-field support
Monthly
$49/mo
Billed monthly, cancel anytime
- ✓Up to 100 fields across unlimited farms
- ✓Up to 5 controller connections
- ✓Daily or weekly digest emails
- ✓Email support
Annual
Best Value$490/yr
Save $98, 2 months free
- ✓Everything in the Monthly plan
- ✓Priority email support
Run Your Own Numbers
One season of water and time savings against a full year of RainRule, with every assumption yours to move
Your operation
Pumping energy or district rate
Deciding, starting, checking
Assumptions you control
Scheduling studies commonly report 10 to 25 percent. The default stays at the low end.
One season, your numbers
- Water savings (on a $3,840 water bill)
- $384
- Time returned (32 hours)
- $640
- Total seasonal savings
- $1,024
- RainRule for a full year
- $490
- Net for the season
- $534
At these numbers the subscription pays for itself 2.1x over in one season.
Estimates, not promises. Every number above is yours to change, and the defaults deliberately sit at the conservative end. Actual savings depend on your crop, soil, weather, and how you irrigate today.
Questions Growers Ask
Who is RainRule for?
Growers who irrigate through equipment they already own: market gardens, hoop houses, plant nurseries, and drip orchards or vineyards running on residential or open-source controllers, plus row-crop operations that want FAO-56 scheduling without a sensor subscription. If your water runs through a Rachio, Hydrawise, or OpenSprinkler, or a pump relay you can put behind a webhook, RainRule can run it. And with nothing connected at all, the recommendations still work.
Do I need soil sensors or a weather station?
No. RainRule runs entirely on live weather data for your farm's location, so recommendations start the day you sign up. If you do run soil probes or flow meters, the equipment API ingests their readings and charts them next to the model.
How does RainRule know how much water to apply?
It implements FAO-56, the irrigation standard published by the UN Food and Agriculture Organization. Reference evapotranspiration comes from Penman-Monteith weather physics, your crop's coefficient scales it by growth stage, and a daily root-zone water balance tracks the deficit in millimeters. When the deficit reaches the refill point for your soil and crop, the prescription is that deficit divided by your irrigation system's efficiency. Every number is auditable arithmetic, not a black box.
Where does the weather data come from?
Open-Meteo, which blends national weather models into hourly forecasts for any coordinates. RainRule pulls conditions and 7-day forecasts for each farm's exact location and refreshes every field automatically through the day.
Which crops does it cover?
29 crops ship with FAO-56 coefficients, stage lengths, and rooting depths: corn, soybeans, wheat, cotton, alfalfa, common vegetables, orchard fruit, and more. You can tune the allowable depletion and root depth per field if you manage differently.
Does it fit my irrigation setup?
Drip, sprinkler, center pivot, furrow, and flood each carry their own application efficiency, so the prescribed depth reflects what must leave the pipe, not just what the soil needs. Prescriptions display in millimeters or inches, with total volume for the field's mapped area.
Can RainRule start my irrigation for me?
Yes. Connect a Rachio, Hunter Hydrawise, or OpenSprinkler controller, or point the signed webhook at your own pump relay or PLC bridge. RainRule discovers the zones, you map them to fields, and each field runs in review mode (you approve every proposed run by email or dashboard) or auto mode (runs queue inside your watering window). Recommendations keep working with nothing connected at all.
What keeps automation from overwatering a field?
Every run is bounded by your watering window, a max runtime cap, and a rain-skip threshold you set per field. The planner refuses to schedule when rain is in the forecast, the water balance is stale, or the controller connection is failing. And if a start command times out, RainRule never retries it blindly, because it cannot know whether water started flowing. The run is marked failed and you get an email immediately.
Do I need to replace my irrigation hardware?
No. RainRule sends commands to equipment you already own: Rachio and Hydrawise through their cloud APIs, OpenSprinkler directly, and anything else through an HMAC-signed webhook you can terminate at a relay, PLC bridge, or vendor gateway. There is no proprietary base station to buy and no subscription tied to hardware.
What happens when the free trial ends?
The trial is 14 days with up to 3 fields and no card required. When it ends, editing pauses but your farms, fields, and history are kept. Subscribe and you pick up exactly where you left off.
Can my agronomist or software talk to it?
Yes. Scoped API keys expose fields, schedules, and water balances over a documented REST API, accept sensor readings in batches, and export boundaries as GeoJSON for GIS tools or ISOXML for tractor terminals.
Water Smarter Starting Today
Join growers who replaced guesswork with forecast-driven precision, and cut water costs in the process
No credit card required. All weather data included free