An irrigation zone is a group of sprinklers that operate simultaneously from a single valve. Proper zone design is critical — it determines how evenly your landscape is watered and how efficiently water is used.

Why Zones Are Needed

Your water supply has a limited flow rate. A typical ¾" residential meter provides 30–55 l/min, while a 1" meter provides 55–95 l/min. You cannot run all sprinklers at once — they would each get insufficient pressure and flow. Zones let you water sections sequentially.

Additionally, different parts of your landscape have different water needs: sunny turf areas need more water than shaded shrub beds. Zones let you customize run times for each area.

Zone Grouping Rules

Follow these five rules for effective zone design:

  1. Same head type per zone — Never mix spray heads (30–50 mm/h) with rotors (10–15 mm/h) or drip emitters on the same zone. Different precipitation rates cause uneven watering.
  2. Same sun exposure — Group full-sun areas separately from shade. Sun areas need 30–50% more water.
  3. Same plant type — Turf zones separate from shrub zones. This is called hydrozoning.
  4. Stay within flow budget — Total flow of all heads in a zone must not exceed 75% of available supply (safety factor).
  5. Similar slope — Flat areas and slopes should be separate zones to prevent runoff on slopes.

Calculating Available Flow

Use the bucket test: open an outdoor faucet fully, fill a 20-liter bucket, and time it. Flow (l/min) = 20 ÷ seconds × 60. Multiply by 0.75 for your design flow.

Example: Bucket fills in 25 seconds → Flow = 20 ÷ 25 × 60 = 48 l/min → Design flow = 48 × 0.75 = 36 l/min per zone

Sizing Zone Valves

Choose valve size based on maximum zone flow:

  • ¾" (20 mm): up to 25 l/min
  • 1" (25 mm): up to 55 l/min
  • 1½" (40 mm): up to 115 l/min
  • 2" (50 mm): up to 190 l/min

Valve pressure loss is typically 1.4–2.8 m of head (2–4 psi). Include this in your pressure budget.

Zone Flow Budget Example

For a zone with 6 MP Rotator heads at 6 l/min each = 36 l/min total:

  • Static pressure: 3.5 bar
  • Water meter loss: −0.35 bar
  • Backflow preventer: −0.52 bar
  • 15 m mainline (32 mm PE): −0.03 bar
  • 1" zone valve: −0.14 bar
  • 20 m lateral (25 mm PE): −0.23 bar
  • Fittings (10%): −0.02 bar
  • Elevation +1.5 m: −0.15 bar
  • Available at head: 2.06 bar (above 1.7 bar minimum for MP Rotators ✓)

Hydrozoning for Water Efficiency

Group plants by water needs:

  • Very high (Kc 0.7–0.9): Cool-season turf, annual flowers
  • High (Kc 0.5–0.7): Warm-season turf, tropical plants
  • Moderate (Kc 0.3–0.5): Most shrubs, perennials
  • Low (Kc 0.1–0.3): Native plants, succulents

Hydrozoning combined with smart controllers can reduce water use by 35–50% compared to single-zone systems. Читайте також: nozzle selection guide. Читайте також: hydraulic calculations. Читайте також: water conservation.

Design in SmartPluvia

Our SmartPluvia planner automatically validates zone flow budgets and warns when you mix head types. Draw your zones visually and let the software check your hydraulics.