Free Landscaper Calculator

Irrigation Flow Calculator

Design irrigation zones correctly — calculate total flow, recommend pipe size and get run time for summer watering requirements.

Zone Details

Frequently Asked Questions

How many sprinkler heads per zone?

For typical residential supply (25 L/min at 300 kPa), pop-up rotary heads at 2 L/min each allow up to 12 heads per zone. Pop-up spray heads at 0.8 L/min allow 30+ heads per zone. This calculator shows total flow so you can compare against your water supply.

How long should I run my irrigation system in summer NZ?

Lawn typically needs 25 mm of water per week in summer. For pop-up rotary heads with 10 mm/hr precipitation rate, that is 2.5 hours per week, or about 22 minutes per day with daily watering. This calculator shows the recommended run time per zone.

What pipe size for irrigation mains?

For up to 15 L/min, 15 mm poly pipe is adequate. 20 mm handles up to 30 L/min and is the standard main line for residential systems. Commercial systems with multiple simultaneous zones should use 25–32 mm mains.