Designing a 1-Acre Irrigation System from a Point Well: Mainline Layout and Wiring

Key Design Principle: Distributed Valves Along a Mainline

Don't centralize all valves at the well. Run a mainline (1" or larger PVC) down the center of the property. Install valve manifolds at intervals, each serving a zone perpendicular to the mainline. This minimizes pipe runs and wire pulls.

Well Capacity Determines Zone Size

Critical unknown: well output (GPM at pressure). Example: 20 GPM well + 4 GPM heads = 5 heads per zone. Measure actual GPM before finalizing design.

Wiring Strategy

• Use 18-gauge multi-strand direct-burial wire (2–15 conductors).
• For a 3-valve manifold: run 18/5 wire (3 hot + 1 common + 1 spare).
• Pull wire with the pipe puller when installing mainline — attach wire to pipe head.

Zone Layout Example

• Mainline to backyard: valves for back zones.
• Mainline to front yard: valves for front zones.
• Mainline to side yard: valves for side zones.

This approach balances hydraulics, reduces trenching, and simplifies troubleshooting.