Why flow sensors make sense for smart irrigation

By Laura Ory on July 1, 2019 in Blog8 Comments

Why flow sensors make sense for smart irrigation graphic

As the cost of water rises and more people strive for smarter water use, flow sensors are becoming an important addition to irrigation systems.

A flow sensor measures your irrigation water use and flow and can work with an irrigation controller to:

  • Stop sprinkler geysers
  • Alert you to broken pipe and other leaks
  • Prevent plant loss from over or under watering
  • Measure and monitor irrigation water use

Today, many smart irrigation controllers have the ability to read flow sensor data. The flow sensor sends a digital pulse to the controller and the controller interprets the information to measure water use, and alert you to a “no flow” zone, a leak or other issues.

Large parks and golf courses have been using flow sensors and controllers that monitor flow for years, but now this technology is more affordable and easier to install for homeowners and other irrigation users that want to be smart about their irrigation water use.

What’s the difference between a water meter and a flow sensor?

Water meters typically only measure the total water use on a property, both indoor and outdoors.

A flow sensor or flow meter, however, can measure your irrigation water use separately, as well as the rate of flow. This is useful for detecting high or low flow rates that may indicate a problem, such as a broken valve or a leak.

How can a flow sensor help save water?

If your goal is to reduce water use, then a flow meter can help you track the success of your efforts and help you figure out if the strategies you are using in the landscape are reducing your water use over time.

It can also prevent water waste due to leaks. Even a very small irrigation leak can waste up to 6,300 gallons of water per month, which could cancel out your other water conservation efforts!

Any new irrigation system should have three things installed to prevent major water loss from leaks: a smart controller, a master valve and a flow sensor.

Master valves are placed before any zone valves. In case of a water line break or a valve that won’t close, the master valve can be used to shut off the water supply to the irrigation system.

Many smart irrigation controllers have compatible flow meters or flow sensors that can be used to detect leaks. These new technologies are more affordable than ever before and make it easy to prevent damaging leaks.

How do I select a flow sensor?

Flow sensors are offered in various sizes, but should be selected based on the high and low flow rates that need to be measured, not the pipe size.

Most often, the minimum flow rate is more important to consider, especially on systems with water-efficient rotors and drip irrigation that reduce irrigation zone flow rates.

For example, a 2-inch flow sensor can easily handle the design flow rate of a 3-inch pipeline without exceeding maximum flow rate and will also measure flow at more critical lower flow rates than a larger sensor would.

New Flow Sensor Technologies

Flow sensor technologies are continuing to improve for use in residential systems, from technology to improved affordability.

For example, the FLOMEC QS200 Insertion Ultrasonic Flowmeter, a best new product winner at the 2018 Irrigation Show, is able to accurately read flow rates using new ultrasonic technology to detect low flow leaks that most other sensors can’t detect.

Featured Flow Sensor: Enhanced Low Flow Sensor (ELF) by Creative Sensor Technology

CST ELF Flow SensorThe new Enhanced Low Flow (ELF) sensors from CST measure rate of flow .20 to 20 GPM, make it possible for one sensor to measure the demand of small drip zones as well as multi-zoned residential and commercial landscape sites.

The ELF sensors are available in a 3/4-inch PVC socket or 1-inch threaded Noryl versions,  are compatible with most smart irrigation controllers.

The ELF also eliminates the need for straight pipe sections up and downstream of the sensor and solenoid valves may be connected directly to the downstream end of threaded ELF model for a flow sensor/master valve for installation in tight spaces.

Why flow sensors make sense for smart irrigation graphic
Laura Ory
Find your nearest Ewing location at

8 Responses to Why flow sensors make sense for smart irrigation

  1. Vipul Patel December 15, 2016 at 3:05 am #

    Flow sensors are extremely useful for measuring irrigational water usage. It is very informative blog. Flow sensors must be used for measuring water as it can help a lot to carry out proper irrigational activities.

  2. Nathan Gant February 22, 2017 at 7:46 am #

    2-wire pulse-output flow meters can be used on irrigation mainlines. You can push flow data to cloud with wireless pulse counters and cellular or ethernet gateways. Also 3-wire hall-effect flow sensors are much cheaper and can also be used with some additional low-cost hardware.

  3. tony October 25, 2017 at 10:13 am #

    must i have a flow sensor for every zone…or can i use one flow sensor just before the valves ?
    do i need a flow meter and a flow sensor? thx

    • Ewing Irrigation & Landscape Supply October 25, 2017 at 3:29 pm #

      Hi Tony,

      Flow sensors/meters monitor flow through your system. You just need one. You need a single flow sensor before the zones near the point of connection (POC), like this: POC > Master Valve (optional) > Flow Sensor > Zone Valves.

  4. Randi October 3, 2020 at 9:00 am #

    I need a smart flow meter for my hatchery

    • Robyn Hazen October 5, 2020 at 2:26 pm #

      Hi Randi – Here is a link to find the Ewing branch near you. Swing by and we’d be happy to talk about smart flow meters:

  5. Joshua Monroy December 21, 2020 at 9:40 am #

    Do flow sensors shut down a master valve when a hose bib is being used? Do you need a separate mainline for hose bibs when using a flow sensor and master valve.

    • Robyn Hazen December 23, 2020 at 2:19 pm #

      Hi Joshua – If a hose bib is put in the mainline after a master valve, the flow sensor may trigger shut down of the master valve. Opening the hose bib could be triggered to the flow sensor as a leak. Best practice is to separate the hose bib from the master valve and flow sensor. Either the hose bib should go before the master valve and flow sensor in the line or use a separate mainline. One reason for placing the hose bib before or separate from master valve is after winterizing your irrigation system, you do not want to re-start the whole system again to use the hose bib.

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