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. Place a 5-gallon bucket under your outdoor spigot
2. Turn the spigot full on
3. Time how long it takes to fill (usually 30-90 seconds)
4. Calculate: (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. **Mark sprinkler locations** with flags before digging
2. **Dig trenches** 6-8 inches deep for PVC mainlines, 4-6 inches for laterals
3. **Install valves** in accessible valve boxes near the water source
4. **Connect mainline PVC** with primer and cement (let cure 2+ hours before pressurizing)
5. **Run lateral pipes** to each head location
6. **Install spray heads/rotors** at grade level (flush with soil surface)
7. **Lay drip tubing** on soil surface under mulch (do not bury)
8. **Run valve wire** in the same trench as pipe, 6 inches deep
9. **Connect controller** and program zones
10. **Test 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
| Component | DIY Cost | Pro Install |
|-----------|---------|-------------|
| Timer/Controller | $80-200 | $200-400 |
| Valves + Boxes | $60-120 | $150-300 |
| Pipe + Fittings | $100-300 | $300-800 |
| Heads/Emitters | $50-200 | $200-500 |
| Backflow + Misc | $50-100 | $200-400 |
| **Labor** | **$0 (your time)** | **$800-2,000** |
| **Total** | **$340-920** | **$1,850-4,400** |
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 →](/design)