Retrofit or Replace? A Contractor's Guide to Adding Smart Control to Existing Irrigation

Most smart irrigation upgrades start with a customer who wants their sprinklers to stop running in the rain. Whether you retrofit the system or swap the controller depends on what is already in the wall and in the ground.

What does CuraTech add for your customers?

CuraTech is a retrofit that turns a customer’s existing system into sensor-based watering plus automatic treatments, with refill revenue for you:

• No rip-out. It retrofits onto the existing irrigation with no new tubing. The CuraTech controller replaces the customer’s existing controller, and the valves, wiring, pipe and heads stay. A certified dealer confirms fit first, then installs it, typically in about a day.
• Not limited to one or two sensor terminals. Wireless soil moisture sensors, up to 100 per property.
• Treatments through the same heads. A multi-pod dispenser meters mosquito, deer repellent, fertilizer, crabgrass prevention and more into the zones the owner chooses.
• Rules built in. It waters and fertilizes only when the soil needs it, respects local watering days and fertilizer blackout dates, and logs every decision and its reason in the app.
• Repeat business. Dealers earn on the install and on treatment refills for the life of the system.
• Less water. We estimate about 40% less water.

Founding dealer spots are limited. See the dealer program.

When is a controller swap unnecessary?

A new controller is not always the best answer. If the box works, the wiring is sound and the customer’s goal is simple, an add-on can do the job for less labor.

EPA’s WaterSense program says both weather-based and soil moisture-based controls can be “add-on” or “plug-in” devices used with an existing clock-based controller. That is the core of a retrofit irrigation system job. You keep the controller and add the intelligence around it.

Use this table on the first visit.

If most answers land in the left column, start with a retrofit. If two or more land on the right, quote a replacement as well.

What does a smart irrigation retrofit involve?

A retrofit adds inputs to a controller that already runs the valves. The common pieces are:

• Rain and freeze sensors. Wired or wireless shutoff switches tied to the sensor terminal.
• Soil moisture sensors. Buried in the root zone. They allow or block a scheduled cycle based on what the soil holds.
• Wi-Fi modules. Some controllers take a plug-in module. Rain Bird says the ESP-TM2 can become a Wi-Fi controller by installing its LNK2 module, and that adding the LNK2 and a WR2 rain sensor gives it EPA WaterSense certification.
• Flow meters. Installed on the mainline after the backflow. They report water use and catch breaks.

Labor depends on how hard the controller and mainline are to reach. A wireless rain sensor is a short visit. A buried soil sensor means trenching a sensor cable or using a wireless unit. A flow meter means cutting into the mainline. Walk the site before you quote, and price each piece as its own line.

Why do most residential controllers take only one or two sensors?

Residential controllers are built for a simple shutoff. Most give you one or two sensor terminals, and that limit shapes every retrofit.

The math gets tight fast. On a two-input controller, a flow meter takes one input and a rain sensor takes the other. Rachio’s support page says it cannot support more than two flow meters on one controller. If the customer wants soil sensors too, you are out of terminals.

That is when a replacement or a separate add-on system starts to make sense. Check the spec sheet for the exact model on site before you promise anything.

How do two-wire systems and decoders change a retrofit?

A conventional system runs one wire per valve back to the controller, plus a common. A two-wire system runs a single cable path. Decoders at each valve listen for their address and open the solenoid.

Two-wire is common on larger and commercial sites. Rain Bird’s ESP-LXD is one example. It manages up to 50 stations out of the box and expands to 200. It also uses decoders for sensor and flow inputs, which gives you more room than a residential box.

For a retrofit, the rule is simple. Match the decoder brand and model to the controller. Two-wire decoders are not interchangeable across brands. If a past owner mixed parts, fault-finding can eat the job’s margin. Diagnose the path before you quote add-ons.

How do flow sensing and leak detection work?

A flow meter turns a controller into a monitor. It reports how much water each zone uses, and the controller compares runs.

Hydrawise controllers accept any reed pulse-based flow meter on their sensor inputs. Hunter’s HC Flow Meter comes in four sizes, from ¾ inch to 2 inch, with maximum recommended flows from 15 to 105 GPM, per the same spec page. Size the meter to the system’s real flow, not just the pipe.

The payoff is service work you can see. A high-flow alert points to a broken head or lateral. A low-flow alert points to a clogged nozzle or a valve that did not open. Both turn into repair tickets with data behind them.

Which rebates help pay for an irrigation controller upgrade?

Florida water managers fund smart controllers, but the rules differ by program. Most require WaterSense labeled equipment.

Tampa Bay Water Wise adds two conditions that matter to you. Installations must be done by a licensed irrigation contractor participating in the program. Homes on reclaimed, well or pond water are not eligible.

Notice what this means for retrofits. The Tampa Bay controller rebate pays for a replacement, not an add-on. If a customer’s main goal is the rebate, the replacement quote may win. Funding and rules change each year, so confirm with the program before you put a rebate on a quote.

Alabama has no statewide equivalent we could verify. Ask the local water utility.

What does Florida require you to check on every job?

Florida law puts the rain sensor on your checklist. Florida Statute 373.62(2) says a licensed contractor who installs or performs work on an automatic landscape irrigation system “must test for the correct operation of each inhibiting or interrupting device or switch on that system.”

If the device is missing or broken, the contractor must install or repair it and confirm it works “before completing other work on the system.” The statute also directs a model ordinance with penalties, which local governments may adopt.

In practice, every Florida service call is a sensor check. That is a natural opening for a retrofit conversation. This is a summary, not legal advice. Confirm local requirements with your county or water management district.

Alabama is different. The Irrigation Association’s state licensing guide does not list Alabama among the states that license irrigation contractors. It notes Florida offers a voluntary license. Check city and utility rules in Alabama, especially for backflow work.

How should you price and position a retrofit?

Sell the outcome, then the parts. Customers do not buy a sensor terminal. They buy a system that skips the rain and tells them when something breaks.

A simple structure keeps quotes clear:

1. Diagnostic visit. Test valves, wiring and the shutoff device. In Florida you are already required to check that device.
2. Good, better, best. For example: a rain or soil sensor on the current controller; that plus a flow meter; or a new WaterSense labeled controller with sensors.
3. Rebate line. Show any program the customer qualifies for, with the program’s name and conditions.
4. Service plan. Seasonal checks and alert response.

The retrofit option keeps the price lower and the old controller in place. The replacement option may qualify for a rebate and adds app control. Let the customer choose with both on the table.

The bigger value is the relationship. A system with sensors and flow data creates reasons to come back. Each alert is a reason to call.

Where does CuraTech fit?

CuraTech is built for the case where the customer wants more than a shutoff, and you do not want to rip anything out. You swap the controller for ours and leave the rest of the system in the ground. Owners reorder refills in the app. First installs with founding dealers start in Q1 2027 in Florida and Alabama.

Read how soil moisture sensors and fertilizer through the sprinkler system work, or point homeowners to early access. See the contractor page for founding dealer details.