Flag Drip Emitters


Flag Drip Emitters

Flag Drip Emitters

DIG Flag Drip Emitters have a unique style that includes a barbed outlet to extend a 1/4″ micro tubing to the plant area. They are available with a flow of 1, 2 and 4 GPH and an operating pressure range of 10 to 25 PSI (the higher the pressure, the higher the flow). The flag drip emitters are available in packs of 5, 25 and 100, each with a 1/4″ self-tapping barbed inlet and barbed outlet. The flag drip emitter’s two-piece construction allows it to be taken apart for cleaning, by twisting the flag part counter clockwise and pulling it apart. Use for an individual plant, planter boxes, small to large pots, groundcovers, shrubs and trees on short runs, level terrain or low-pressure gravity feed drip irrigation installations.


  • Available in three colors so that it is easy to identify flow rate
  • Self-tapping barbed inlet for easy installation
  • Outlet barb for use with 1/4″ micro tubing
  • Spiral flow through a large-flow-path water passage reduces likelihood of clogging
  • Twist-open top with lock for secure operation under pressure and for easy cleaning
  • Durable high-impact plastic
  • Resistant to chemicals and fertilizers used in landscape application
  • Constructed of UV-resistant, durable plastic material to withstand the most adverse conditions


How to Order
1 GPH Black
FN1A 1 GPH Flag Drip Emitter (pack of 5)
FN1B 1 GPH Flag Drip Emitter (pack of 25)
FN100 1 GPH Flag Drip Emitter (pack of 100)
2 GPH Green
FN2A 2 GPH Flag Drip Emitter (pack of 5)
FN2B 2 GPH Flag Drip Emitter (pack of 25)
FN200 2 GPH Flag Drip Emitter (pack of 100)
4 GPH Red
FN4A 4 GPH Flag Drip Emitter (pack of 5)
FN4B 4 GPH Flag Drip Emitter (pack of 25)
FN400 4 GPH Flag Drip Emitter (pack of 100)


  • Operating pressure range: 10 to 25 PSI
  • Recommended operating pressure: 25 PSI (use with model D46 25-PSI pressure regulator)
  • Flow rates and color codes:
    • 1 GPH (4 L/H) color code – black
    • 2 GPH (8 L/H) color code – green
    • 4 GPH (16 L/H) color code – red
  • Inlet side: 1/4" self-tapping barb
  • Outlet side: 1/4" barb
  • Filter requirement: minimum of 150 mesh
  • Material: body and cover: polypropylene

Flow rate in gallons per hour @ 5 to 30 PSI

Color Black Green Red
Nominal flow rate 1 GPH 2 GPH 4 GPH
5 PSI .5 .77 1.72
10 PSI .79 1.21 2.81
15 PSI 1 1.61 3.61
20 PSI 1.22 1.95 4.29
25 PSI 1.39 2.19 4.92
30 PSI 1.55 2.44 5.51

Maximum number of 1 GPH black drip emitters on 1/2" drip tubing with .600 ID

Drip emitters spacing 1' 2' 3' 4'
Flow rate @ 25 PSI 1.39 1.39 1.39 1.39
Maximum length 124 192 249 304
Flow rate in GPM 2.87 2.22 1.92 1.76
Flow rate in GPH 172.4 133.4 115.4 105.6
# of drip emitters 124 96 83 76
Velocity (f/s) 3.26 2.52 2.18 2.0
Total head loss in PSI 5.5 5.19 5.05 5.23

Maximum number of 2 GPH green drip emitters on 1/2" drip tubing with .600 ID

Drip emitters spacing 1' 2' 3' 4'
Flow rate @ 25 PSI 2.19 2.19 2.19 2.19
Maximum length 91 144 186 224
Flow rate in GPM 3.32 2.63 2.26 2.04
Flow rate in GPH 199.3 157.7 135.8 122.6
# of drip emitters 91 72 62 56
Velocity (f/s) 3.77 2.99 2.57 2.32
Total head loss in PSI 5.2 5.22 5.09 5.07

Maximum number of 4 GPH red drip emitters on 1/2" drip tubing with .600 ID

Drip emitters spacing 1' 2' 3' 4'
Flow rate @ 25 PSI 4.29 4.29 4.29 4.29
Maximum length 59 94 120 148
Flow rate in GPM 4.22 3.36 2.86 2.65
Flow rate in GPH 253.1 201.6 171.6 158.7
# of drip emitters 59 47 40 37
Velocity (f/s) 4.79 3.81 3.25 3.01
Total head loss in PSI 5.1 5.38 5.02 5.31
*Based on around 90% flow uniformity and 0% slop


The 1, 2 and 4 GPH Flag Drip Emitters consist of two parts, the top flag (wing) insert with a large spiral water passage that can be twisted to open and remove for cleaning, and the body. The large-water-path design allows particles to pass through the drip emitter’s water passage, providing reliable performance and a longer life. One of the main features of these drip emitters is their ability to operate under very low pressures and with lower flow rates making them ideal for gravity feed systems. The three models have preset flows of 1, 2 or 4 GPH at a nominal pressure of 15 PSI and can operate under a pressure range of 5 to 25 PSI.

The emitters may be installed using one of three methods; either directly into the drip tubing, into the drip tubing and extended with micro tubing to the plant and secured to the ground with stabilizer stake or at the end of the micro tubing. Within the layout, we highly suggest that a minimum of two drip emitters should be placed on opposite sides, under the plant canopy, centered between the plant trunk and the plant canopy edge.

When using single drip emitters, it is important to select the correct flow rate in order to achieve a wetted pattern shape that can cover at least 70% of the plant root zone. In sandy soil, water tends to drain quickly (gravitational force) with little lateral movement, so applying a higher flow rate over a given time period will produce a wider pattern. Using .5 GPH drip emitters for one hour will provide a smaller wetted area then using 1 GPH emitters for the same time, due to the soil characteristics.

One of the most common installation errors in installing drip irrigation is using too few emitters. All too often only a single emitter with preset flow is placed at the base of a newly planted tree, shrub or roses. In clay soils, a single drip emitter can wet a three to four foot diameter; on sandy soils, the same layout using the same drip emitter will only wet an area of few inches only. Given the fact that plant roots can grow up to a few feet a year depending on the plant and location, after one year the diameter of the root system would be much larger than the area covered by the one drip emitter. A single drip emitter per tree or shrub could restrict root development as early as the first year after planting if flow is not adjusted or a drip emitter is not added. We highly recommend adding more than one drip emitter per plant, depending on plant size.

Installation suggestions

Basic installation recommendations for this product include first reviewing the area and then making a drawing of the garden or site with your preferred layout. If automation is required, use one of DIG’s hose end timers or battery operated controllers. The ideal controller should have flexible scheduling and two to four start times per day for added flexibility.

Start the installation from a PVC pipe or to pipe thread

Recommendations: Wrap all male pipe thread fittings with Teflon tape. Do not use pipe cement on the valve as it will damage the valve and void the warranty.

  1. If the system installation is started from a PVC pipe, first shut off the main water supply.
  2. If an automated system is preferred, we recommend installing a 3/4″ ball or gate valve before the battery operated controller or AC valve (if used). This ball valve can be very useful as an emergency backup to turn the system off. This type of arrangement is used by professional installers.
  3. Turn the water supply on to flush the line and then shut the water supply off using the new ball or gate valve.
  4. Install an AC valve or battery operated controller, wrapping TEFLON tape on the male pipe thread fittings.
  5. Turn the water supply on again to pressurize the system. The unit will open momentarily and then will shut off.
  6. Test the valve or the battery operated controller and make sure that it is working correctly.
  7. After the AC valve or battery operated controller, add a 3/4″ screen filter with 155-mesh (model D55). The screen filter is used to protect the drip system. Then, add a preset 25 PSI pressure regulator (model D46P) or adjustable pressure regulator (model PRV075). The pressure regulator is used to lower the pressure to the suggested operating pressure for a drip system. Follow with a 3/4″ swivel adapter (model 50001) to the drip tubing or 3/4″ PVC thread x slip adapter to the PVC line.

Start the installation from a faucet or hose thread

  1. If an automated system is preferred, install a hose end timer.
  2. Test the hose end timer and make sure that it is working correctly.
  3. After the timer, add a backflow device (model D45) and then a 3/4″ filter (model D57A) to protect the drip system. Next, install a 25 PSI pressure regulator (model D46) to lower the pressure to the drip system, followed by a swivel adapter (model C34) to connect the drip tubing.

Product installation

  1. Using the drip tubing as the main lateral or as a sub lateral, lay out the drip tubing per your layout drawing. Secure the drip tubing to the ground using stakes (model R60) in key areas and add more stakes as you unroll the drip tubing. Add stakes every 20′-30′ and at the end of each section, or as needed. An extra 1% of drip tubing length should be added to each lateral to compensate for contraction at low temperature.
  2. Throughout the installation and per your drawing layout, add, if needed, 1/2″ fittings, such as tees (model C35) and elbows (model C36), leaving the end of the drip tubing open. To install the 1/2″ compression drip fittings, cut the drip tubing with a hand pruner, being careful to keep dirt from entering the line. Hold the fitting in one hand and the drip tubing in the other and force the drip tubing into the compression fitting by wiggling it from side to side.
  3. The drip emitters are installed along the drip tubing at varying or specific intervals. The distribution uniformity of water from the drip emitters along the line depends on the incoming pressure, number of drip emitters used per lateral and the length of the laterals. Special care should be taken to ensure high uniformity of water along the laterals by not exceeding the product recommendations (see Product Specifications).
  4. To install the drip emitter, you may use one of the options suggested:
    • Option 1: Punch a hole into the drip tubing using the small punch (model D44) or the gun punch (model 16-035), and snap the barbed side of the drip emitter into the drip tubing
    • Option 2: Install the drip emitter into the micro tubing by cutting a length of two to four feet (we highly recommend not exceeding four feet) of 1/4″ micro tubing (vinyl – models B38 for 50′ and B38100 for 100′, or poly – models B38P for 50′ and B38100B for 100′). To the micro tubing end, insert a 1/4″ barb (models H80A for pack of 10 and H80B for pack of 50). To the other end of the micro tubing, insert the barbed side of the drip emitter, add a stabilizer stake (model P35B for pack of 10) and secure to the ground. Punch a hole into the drip tubing using the small punch (model D44) or the gun punch (model 16-035), and insert the 1/4″ barb at the end of the micro tubing into the drip tubing.
  5. Turn the water on and flush the line.
  6. Close the end of the drip tubing using the hose end (model Q58) or figure “8” (model F68B).
  7. Pressure-test the system to identify leaks in the drip tubing laterals, fittings and micro tubing and then program the hose end timer or battery operated controller.