Florida Water Star
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Florida Water Star Technical Manual

Irrigation system criteria

Distribution (application) uniformity

Sprinkler spacing


Distribution uniformity is increased by head-to-head spacing. This occurs when sprinkler heads are located a distance of 50% of the nozzle throw diameter from the adjacent head. In other words, a sprinkler head with a 10-foot throw should be spaced 10 feet from the adjacent head. This spacing must occur in all directions that the nozzle is throwing.

Head-to-head spacing of sprinklers

Head-to-head spacing of sprinklers.

Example of head-to-head spacing

Example of head-to-head spacing.

Requirements and certification

Head spacing does not exceed 50% of the nozzle’s throw diameter.







Sprinkler head zones must have head-to-head spacing with no more than 1-foot variance. The following should also be considered:

  • Narrow side yards graded for drainage and adjacent to similarly landscaped zones may have single-row spacing.
  • Every corner area should have an irrigation head.
  • An irrigated rectangular landscape area should have head spacing that is equal to its width.
Rectangular spacing of sprinkler heads

Rectangular spacing of sprinkler heads.

Triangular spacing of sprinkler heads

Triangular spacing of sprinkler heads.

  • Triangular spacing, while potentially more uniform in some situations, can create significant overspray when used in small areas and adjacent to impervious surfaces.

Irrigation drawings must depict head-to-head spacing, and any notes associated with design drawings should confirm this requirement. The Florida Water Star Inspector will visually inspect for this prerequisite while each zone is running.

When irrigating turf in side yards or right of way areas 4 feet wide or greater, it can be possible to use a single row of sprinklers if ALL of the following conditions are met:

  1. There is adequate slope away from the single row of sprinklers to provide surface water movement.
  2. The sprinkler spacing is reduced to a maximum of 40% of radius (closer than head-to-head) to compensate for the lack of a second row of sprinklers and increasing the precipitation rate slightly to assist in the surface water movement.
  3. The sprinklers are on a separate zone in order to time this specialty application separately from all other zones AND the runtime and cycles for that zone are correct to minimize wasted water.
  4. The sprinklers are adjusted to minimize overspray beyond the zone.

Notes: FWS allows a one foot variance on location in this criteria. All areas less than 4 feet wide must be irrigated with micro spray or drip. If turf is not required to be in these areas, consider a groundcover species and microirrigation.

Program tip

Locations that consistently receive greater wind speeds might require even closer spacing. Designers and installers should be aware of any such locations and make changes accordingly.

St. Johns River Water Management District
4049 Reid Street, Palatka, FL 32177