DIY Irrigation System: Complete Planning and Installation Guide

An irrigation system is the single best investment you can make in your landscape's long-term health. Plants watered by drip irrigation grow 30-50% faster than hand-watered plants because they receive consistent, deep moisture right at the root zone.

Here's how to design and install one yourself for $200-$800 (vs. $2,000-$5,000 professionally installed).

Step 1: Map Your Zones

The fundamental rule of irrigation design is hydrozoning — grouping plants by water needs:

Zone 1 — High Water (Spray/Rotor):

• Lawn areas, annual flower beds, vegetables
• Water 3-4x per week, 30-45 minutes
• Use spray heads (small areas) or rotary nozzles (large areas)

Zone 2 — Medium Water (Drip):

• Most perennials, shrubs, established hedges
• Water 2x per week, 60 minutes
• Use 1/2" drip tubing with emitters every 12-18"

Zone 3 — Low Water (Drip, Infrequent):

• Native plants, ornamental grasses, drought-tolerant species
• Water 1x per week (or rain-only once established)
• Use 1/4" drip tubing with emitters every 24"

Never mix spray heads and drip on the same zone. They require different pressures and run times.

Step 2: Calculate Water Supply

Before designing anything, measure your available water:

1. 1Place a 5-gallon bucket under your outdoor spigot
2. 2Turn the spigot full on
3. 3Time how long it takes to fill (usually 30-90 seconds)
4. 4Calculate: (5 gallons ÷ seconds) × 60 = gallons per minute (GPM)

Most residential supplies provide 5-15 GPM. You need to know this to size your zones — each zone can only use a portion of your total supply.

Step 3: Design the Layout

Spray Zone Layout

• Head-to-head coverage: Each spray head's radius should reach the adjacent head. If heads are spaced 12 feet apart, use heads with a 12-foot throw radius.
• Types: Fixed spray (4-15ft radius), rotary (15-35ft radius), impact (25-50ft radius)
• Spacing: Square pattern for rectangular areas, triangular for irregular shapes
• GPM per head: Fixed spray = 1-3 GPM, rotary = 0.5-1 GPM

Drip Zone Layout

• Mainline: Run 1/2" poly tubing as the main loop around planting beds
• Emitters: Pressure-compensating drip emitters at each plant (1 GPH for small plants, 2 GPH for shrubs, 4 GPH for trees)
• Inline drip: For groundcovers and mass plantings, use inline drip tubing with built-in emitters every 12-18"
• Trees: Dedicated emitter ring at the drip line (outer edge of canopy), not at the trunk

Step 4: Parts List

Every irrigation system needs:

• Backflow preventer (required by code) — $30-80
• Timer/controller — WiFi-enabled recommended ($80-200). Rain Bird, Rachio, or Hunter are top brands
• Valves — One per zone ($15-30 each)
• Valve boxes — Protect underground valves ($10-20 each)
• Pipe — 3/4" PVC for mainline, 1/2" poly for laterals
• Spray heads/rotors — $3-15 each
• Drip tubing + emitters — $0.50-1 per linear foot
• Wire — 18-gauge direct burial wire, 1 conductor per valve + 1 common

Step 5: Installation

1. 1Mark sprinkler locations with flags before digging
2. 2Dig trenches 6-8 inches deep for PVC mainlines, 4-6 inches for laterals
3. 3Install valves in accessible valve boxes near the water source
4. 4Connect mainline PVC with primer and cement (let cure 2+ hours before pressurizing)
5. 5Run lateral pipes to each head location
6. 6Install spray heads/rotors at grade level (flush with soil surface)
7. 7Lay drip tubing on soil surface under mulch (do not bury)
8. 8Run valve wire in the same trench as pipe, 6 inches deep
9. 9Connect controller and program zones
10. 10Test each zone — adjust heads for full coverage, check for leaks

Step 6: Programming

Morning watering (6-8 AM) is best. Less evaporation than midday, less fungal disease risk than evening.

Run time formula: Total plant water need (GPH) ÷ emitter output (GPH) = minimum run time in hours.

Seasonal adjustment:

• Spring: 75% of summer schedule
• Summer: 100% (baseline)
• Fall: 50%
• Winter: 0-25% (depending on region)

Rain sensor ($25-50): Automatically skips watering when it rains. Required by law in some states (FL, TX, NJ, CT, MN). Saves 20-30% on water annually.

Cost Breakdown

Your Yardcast design pack includes an irrigation zone map showing which plants go on which zone, with head type recommendations.

Get your design with irrigation plan →