Rotary, Spray, & Drip: Understanding 3 Common Types of Lawn Sprinkler Heads

How pop-up sprinkler heads work

The common style on residential systems is the pop-up. When the zone is off, the head sits flush with the soil, out of sight and out of the way of mowers and foot traffic. When the zone turns on, water pressure pushes a riser up above the turf and the nozzle sprays. When the zone shuts off, a spring pulls the riser back down.

Standard pop-up height is four inches, which clears a typical lawn mowed at three to three and a half inches. Taller bodies are available up to twelve inches for planting beds, ornamental grasses, and anywhere the spray would otherwise be blocked. The nozzle screwed into the head determines the throw distance and the pattern, and the nozzle is usually the cheapest and most consequential part of the whole assembly.

The three main types

1. Spray heads

Spray heads cover smaller areas, typically with a throw of 5, 10, or 15 feet. They are fixed rather than rotating, spraying a set pattern determined by the nozzle: a quarter circle, half circle, full circle, or a strip pattern for a narrow bed.

Because they water their whole pattern at once, spray heads apply water fast. That is useful for small areas and it is also why they cannot share a zone with rotors, which apply water several times more slowly. Run them on one schedule and one group gets far too much or far too little.

If you have an older system, you may have original style spray nozzles that throw a heavy sheet of water and apply it faster than most soils can absorb it. Newer rotating nozzles, which look more like a set of fingers than an umbrella, break the stream into rotating streams and apply water at a much lower rate. The result is less runoff, more even coverage, and less wasted water. Upgrading nozzles is one of the cheapest improvements available on an existing system.

2. Rotary heads

Rotary heads throw the farthest and are built for large open areas. A single rotor can cover 30 feet or more, and the arc is adjustable from a narrow 30 degrees up to a full 360.

Here is the counterintuitive part. Homeowners with small yards often assume a couple of long throwing rotors will cover everything cheaply. Fewer heads, less money. In practice, a small or oddly shaped yard usually costs more per square foot to irrigate, because it needs more heads with shorter throws to fit the shape without throwing water where it does not belong.

Think about the strip of grass between the sidewalk and the street. A rotor there sprays into the road. That strip needs several short throw spray heads instead, and more heads means more trenching, more fittings, and more cost.

3. Drip irrigation

Drip is not a sprinkler head, but it is the third major delivery method and often the right answer. Instead of spraying, drip uses tubing with emitters that release water slowly, directly into the soil at the base of the plant.

Drip uses less water than spray irrigation for the same result, because nothing is lost to evaporation or wind drift and nothing lands on pavement. It is ideal for shrub beds, foundation plantings, and narrow strips where even a short throw spray head overshoots. It works in porch and patio planters too, which solves the daily watering can routine.

One limitation: drip is a poor match for a bed you till regularly, since tilling cuts the lines running just under the surface or the mulch.

Are stainless heads better than plastic?

Mostly no, and it is worth understanding why. On a pop-up head, the stainless refers to a steel sleeve on the riser. The internal components, the seal, the spring, the nozzle, and the body are generally the same as the plastic version. Stainless risers are useful in gritty or sandy conditions where abrasion is a problem, but on a typical residential lawn you are paying for a material difference that does not change performance. The nozzle selection and the spacing matter far more than the riser material.

The mistakes that cause brown spots and soggy areas

Most head problems on homeowner installed systems come down to a handful of errors.

• Wrong head for the area. A spray head where a rotor is needed leaves the far side of the area dry. A rotor in a small area throws water onto pavement and the house.
• Mixing head types on one zone. Rotors and spray heads apply water at very different rates. On the same zone, one group is always wrong.
• Too many heads for the available flow. Every zone has a flow budget in gallons per minute. Add a fifth head to a zone sized for four and pressure at each head drops, throw distances fall short, and in bad cases heads do not fully pop up.
• Wrong nozzle. The nozzle sets both the pattern and the volume. The wrong one leaves a gap in coverage that shows up as a brown crescent in August.
• Poor adjustment. Each head has to be set so the arc and throw land water where it is needed and nowhere else. Adjustment methods differ by brand, and some require a specific tool.

Landscape changes matter here too. Add a bed, move a walk, or plant a tree that grows up into a spray pattern, and heads need to be moved, added, or re-nozzled.

Keep the heads working with regular tune-ups

Heads take abuse, and a Wisconsin or Minnesota winter supplies most of it. Frost heave lifts and shifts them over four or five months of frozen ground, so they come up in spring spraying the driveway instead of the lawn. Soil settles and leaves a head low enough that turf blocks the pattern. Seals wear and leak. Mineral residue and grit flow down the line and clog nozzles. A snowplow or an edger takes a head off at the riser.

None of that announces itself. You find it when an area turns brown or the water bill jumps. Seasonal irrigation maintenance catches it, because someone is running every zone and watching each head perform.