Designing Your Drip Irrigation System
- How far can I run the 1/2” drip poly tubing (mainline)?
The maximum drip mainline run is determined by the flow rate, water pressure, the number of emitters on the line, and distance between the emitters. Our 700 tubing has a maximum flow rate of 240 gallons per hour. We recommend a 20psi or 30psi drip regulator.
For most residential drip irrigation systems using a hose bibb (faucet, spigot, hydrant) as the water supply, follow these guidelines:
Maximum drip mainline run: 500 ft
Maximum emitter output: 240 gallons per hour
Since a typical hose bibb delivers 240 gallons per hour, you can put 240 1 gallon-per-hour emitters on the line (or 480 1/2 gallon-per-hour emitters or 120 2 gallon-per-hour emitters).
This works up to a point. If you run your drip poly tubing over 500 feet, there will be some pressure loss, limiting the number of emitters that you can install. For a maximum length run chart and more details read our tutorial on Installing Drip Tubing and Fittings.
- How far can I run the drip emitter tubing (dripperline)?
The maximum run varies with the size of the tubing and the spacing of the emitters.
Emitter Tubing Guidelines Tubing Size & Emitter Spacing Pressure Compensating Emitters? Max psi Max Run per branch Max Run Total (1/4" is fed from 1/2" mainline) 1/4" Tubing - 6" spacing 1/2 gal/hr No 30 19 ft 200 ft 1/4" Tubing - 12" spacing 1/2 gal/hr No 30 33 ft 400 ft 1/2" Tubing - 12" spacing 1/2 gal/hr Yes 50* 450 ft 1/2" Tubing - 18" spacing 1/2 gal/hr Yes 50* 500 ft 1/2" Tubing - 18" spacing 1 gal/hr Yes 50* 350 ft * We recommend operating at 20 - 30 psi
Pressure Compensating Emitters
- Deliver the stated gph (gallons per hour) even if pressures range is 10-50 psi
- Works well with elevation changes
- Self-flushing to reduce clogging
- Output will vary with changes in pressure & elevation
- Works best with flat landscapes
- Excellent for gravity-fed drip systems
1/2" Compression Fittings
- Recommended pressure: 10-30 psi
- Max pressure: 60 psi
- How many emitters can I put on a mainline?
The number of emitters you can put on a single drip system varries with your available water flow, drip tubing size, and emitter water output. This tutorial will detail how many emitters you can put on a drip mainline.
Our Drip Tubing Maximum Run Chart (PDF) will help you compare different scenarios. The maximum pipe run will increase if you use low-output emitters (1/2 gallon-per-hour). Increasing pressure regulator size from a 20 psi regulator to a 30 psi regulator will also extend the distance that you can run drip main line.
- How do I add on to my existing drip system?
We have a great selection of drip tubing coupling adapters for varying sizes of drip tubing. They are color coded. The first step is to determine the Outer Diameter (OD) of your tubing.
Common OD dimensions are:
.700 inches (called “700") Black fittings - 700 Compression Coupler
.620 inches (called “620”) Green-ringed fittings - 700 x 620 Compression Adapter
.710 inches (called “710”) Blue-ringed fittings - 700 x 710 Compression Adapter
.580 inches (called “580”) Yellow-ringed fittings - 700 x 580 Compression Adapter
.455 inches called "455") Red-ringed fittings - 700 x 455 Compression Adapter
If you find that your existing tubing is not 700, simply add the appropriate coupling adapter to your order to go from your tubing to 700.
View our Installing Drip Tubing & Fittings tutorial for more details.
- Can I bury my drip tubing?
We do not recommend burying drip tubing in the soil. However, a layer of mulch on top will extend the lifespan of the drip tubing. Buy Drip tubing here.
- Can I combine emitters (drippers) and micro sprays on the same line?
You can combine drip emitters, adjustable drip sprayers, and drip micro sprays all on the same poly tubing (mainline) as long as your total gallon output does not exceed the flow rate available. Drip sprayers can use in excess of 30 gallons per hour so keep track of your water output when designing your drip system. For more details, check out these tutorials:
- How do I retrofit my existing sprinkler system to drip irrigation?
There are a few ways to go. Some options require digging down to supply lines and others involve swapping out parts above ground. For details and photos, please read our "Retrofiting Sprinklers for Drip Irrigation" tutorial.