Help & Advice

Impact Sprinklers: What are they and how do they work?

Impact sprinklers ensure efficient, precise watering, keeping gardens vibrant and healthy throughout the year.

Impact sprinklers, also known as impulse sprinklers or impact rotors, feature one of the most common and recognisable sprinkler heads. These user-friendly sprinklers are a favourite among gardeners across the UK. For a lush garden and a green lawn in the summer months, impact sprinklers are a popular garden sprinkler option. In this guide, we discuss the pros and cons of impact sprinklers, how they work, and whether they are the right sprinkler for your gardening needs.

Explore our full range of garden sprinklers today.

What are impact sprinklers?

When it comes to reliability, durability and ease of use, impact sprinklers are a great choice for residential lawns, home gardens, and even professional use. Impact sprinklers feature a type of irrigation sprinkler head that operates by spinning and creating a rotating stream of water. They are often adjustable and can be set to water a partial area or a full circle. Due to their ability to efficiently cover large areas, it’s common to see these sprinklers used in agriculture, sports grounds, and large lawns.

Impact sprinklers normally feature one nozzle and one to two arms that are attached to the head. The base can vary, but the most common impact sprinkler bases are tripod, sled, and spike bases.

Learn more about different types of sprinkler bases in our Ultimate Guide to Garden Sprinklers

How does an impact sprinkler work?

Featuring an outer-facing water jet and a rotary arm, impact sprinklers are designed with ease of use in mind and only require the force of water to operate. Once connected to a water source, water pressure builds in the hosepipe to emit a water jet from the sprinkler head. This jet will hit the rotary arm, an action that rotates the sprinkler head and scatters the water in a neat arc, ensuring an even spray.

As the arm hits the water stream, it returns to its original position, before repeatedly interrupting the jet of water. This back and forth spring-action creates the characteristic clicking noise and ensures repetitive, consistent watering for your lawn.

How to adjust an impact sprinkler

You may need to adjust the height, range, and spray pattern of your impact sprinkler to get the best sprinkler performance for your garden irrigation needs. You can modify the direction and rotation pattern on your impact sprinkler, as well as the range and how powerful the jet is. Each impact sprinkler modelwill be slightly different, but you can usually adjust the rotation pattern between 15 degrees and 360 degrees. Usually, you can adjust the water jet stream on an impact sprinkler using the diffuser pin, with jet stream settings operating between a fine mist to a heavy jet.

You can download the instructions here, or see the instructions below.

1. Diffuser Pin

The diffuser pin is a large screw on the sprinkler head used to difuse the jet of water as it exits the nozzle. If you want to dispurse the water as it exits the sprinkler, screw the pin in a clockwise direction until it disrupts the jet of water. For a more concentrated stream that will go further, unscrew the pin all the way out.

The diffuser pin breaks up the stream, causing it to fan out in a delicate spray or mist. The further the pin projects over the opening, the shorter and wider the spray will be.

2. Deflector Shield

Raise or lower the deflector shield. Swivel the flat metal square attached to the body of the sprayer head (just beside the diffuser pin) up or down. To block the spray from throwing to far, raise the deflector to the upper position.

If you’re trying to water from one end of your lawn or garden to the other, keep the deflector in the lower position. This will allow the stream to travel in a higher arc and cover longer distances.

3. Adjust Arc of Sprinkler

Use the collars to alter the spray pattern. Twist the metal clamps that wind around the base of the sprinkler head into different positions to determine the movement of the sprinkler head. The closer together the collars are, the narrower the watering range.

As the sprinkler turns, the trip pin at the base of the head will run up against the collar clamps, causing the sprinkler to reverse direction.

4. 360° Coverage

Flip up the trip pin for full 360-degree coverage. If you want the sprinkler to rotate all the way around, simply lift the trip pin until it rests up against the sprinkler head. It will then be able to send out water in a smooth, radial motion.

Getting the trip pin out of the way can be helpful if your sprinkler system is located in the centre of the area you’re watering.

Are impact sprinklers good?

Although impact sprinklers are often used for agricultural purposes, they can also be an ideal choice for home gardens. Impact sprinklers easily attach to garden hoses and can connect to a more complex automatic irrigation system with ease. While they are not perfectly suited for every garden, impact sprinklers are an excellent choice for gardeners looking for a reliable and robust irrigation system.

Shop garden sprinklers or explore our Claber, Hozelock and Gardena sprinkler products.

Impact sprinkler advantages:

Highly durable and long-lasting - Impact sprinklers are designed to withstand harsh weather conditions and heavy usage, making them a reliable option for long-term use. The body of the sprinkler is usually made of sturdy materials, such as metal or plastic, and the internal mechanisms are built to last.
Large Coverage Area - Impact sprinklers are capable of efficiently watering large areas - such as large lawns, bowling greens, horse riding surfaces, cricket greens and other large lawn areas. They can cover over 20 meters in diameter, and are especially useful for agricultural irrigation, professional gardening, and the horticultural trade.
Fully adjustable - With adjustable spray distance, pattern, and direction, impact sprinklers are incredibly versatile and suitable for a variety of terrains and irrigation needs.
Easy to maintain - Impact sprinklers are easy to use and easy to maintain. Unlike other sprinklers, such as oscillating sprinklers, impact sprinklers generally feature only one nozzle that is resistant to clogging. They don’t have any small and delicate parts that could become damaged and they are easily cleaned with a damp cloth or soft brush.

Impact sprinkler disadvantages:

Water Waste - Depending on the shape of your garden, the climate, and what needs watering, impact sprinklers may be less efficient than other types of sprinklers. They produce large droplets that are prone to evaporation and wind drift. This can result in uneven watering and water waste.
Noise - The clicking noise created when an impact sprinkler is in use can be noisy. Other sprinklers, such as rotary sprinklers, may be much quieter.
Limited Coverage Patterns - Impact sprinklers are typically designed to cover circular areas. They can be adjusted to spray in different patterns, but they may not be as flexible as other types of sprinklers. If you have a rectangular or square-shaped lawn, an oscillating sprinkler may be more appropriate.

Learn about oscillating sprinklers in our oscillating sprinkler guide.

What is the best impact sprinkler?

I have a few favourite impact sprinklers from varying brands, but my absolute favourite is the Pro Garden Skid with Impact Sprinkler. An all metal construction, it is stable, easy to maneuviure and is very robust. I bought mine about 10 years. It's still working great to this day.

Below is a selection of my top choices for Impact Sprinklers.

Sean's Recommended Impact Sprinklers

Lawn Sprinklers Garden Skid Sprinkler - Pro

Impact sprinkler FAQs

Are impact sprinklers efficient?

Yes, depending on what you are watering, impact sprinklers can be highly efficient as they distribute water evenly over a large area without excessive waste.

How far does an impact sprinkler spray?

The jet spray distance of an impact sprinkler depends on the exact product design and model you buy. It can also depend on the performance of the water source. Typically, an impact sprinkler jet spray will range between six and fifteen metres.

Which is better, an impact or rotor sprinkler?

The choice between an impact and rotor sprinkler depends on the specific needs of your garden. Rotor sprinklers are better for smaller areas and more precise watering. If you are watering a larger area, an impact sprinkler will be better.

Do impact sprinklers need to overlap?

Yes, it is recommended that impact sprinklers overlap by at least 20% to ensure even coverage of the intended area. For best coverage, I recommend having an overlap of 50% (head-to-head).

How do you position an impact sprinkler?

For large areas, position your impact sprinkler in the centre of the area you want to water for maximum coverage. For smaller areas, place the sprinkler on the edge or in the corner of the area and set the sprinkler arc to match.

Adjust the spray pattern to your preferred calibration, and make sure that the sprinkler is completely level. This will help ensure even water distribution.

How long should I water my lawn with an impact sprinkler?

The length of time you should water your lawn with an impact sprinkler depends on factors such as the type of soil and weather conditions. As a general rule, it is recommended to water heavily but infrequently, with a target of putting down 25mm of water. To acheive this, we recommend watering your lawn for about 30 - 60 minutes at a time, once or twice a week with an impact sprinkler.

Discover our complete selection of impact sprinklers in our garden sprinkler collection, otherwise explore our sprinkler products from leading brands including Claber, Hozelock and Gardena. For additional guidance on garden irrigation, please see our Help & Advice page, and do not hesitate to reach out to us with any questions!