Deciding on which sprinkler heads are best for you and your lawn is an important decision to make when setting up an above ground lawn irrigation system. It can be difficult to choose between impact sprinklers and rotating sprinklers that are gear driven because they both have their own distinct advantages.
Both rotary and impact sprinklers will work just fine to properly irrigate a lawn but they do have differences that can make one style perform better than the other in different situations. Let me explain briefly before we get into this topic even deeper.
Rotary sprinklers are driven by internal gears that disperse the water exactly where you want it in the desired volume. For this reason rotating sprinklers are usually the best sprinkler for water conservation as a fine tuned sprinkler system can waste very little water. Impact sprinklers cannot be fine tuned as much so they tend to use more water to cover the same area, however an impact sprinkler can usually cover more area than a single rotor sprinkler head.
Another quick thing to mention is the durability of these two types of sprinklers. Impact sprinklers tend to be better made – assuming you stay away from the cheap plastic versions.
For instance, I want to first point you towards this impact sprinkler by Orbit. It’s extremely durable and doesn’t cost too much for something so durable. Most notably I want you to take a look at the reviews – they are super high.
In comparison, this popular hose-end rotary sprinkler by Rain Bird may cost a little less but it’s reviews are not quite as good.
From my experience this is a trend that I see in these product types. Basic impact sprinklers are built to last and they work great. You pay for that quality though.
If you are truly looking for the highest quality though then you should consider looking into the smart gear drive sprinkler market. These are sprinkler heads that not only dispurse water exactly where you want it but also adjust to different fluid radius distances around the arc. Basically, the smart heads can throw water anywhere from around 5-feet to 30-feet at each point around the circumference of a sprinkler zone so that the pattern can adjust for diagonal lines in paved surfaces, garden beds, or rounded lines.
Only a minority of companies make sprinkler heads like this, but they are the most durable of them all and they use the least amount of water of them all too. I use the heads from Irrigreen but a couple other companies like Otto Lawn make similar alternatives. You can see my experience installing Irrigreen sprinklers, along with video footage of how the pattern looks, here for more context.
Of course, setting up a well-designed rotary sprinkler system can also be a challenge and because impact sprinklers can usually be adjusted more than most people realize it’s hard to encourage everyone to opt for rotary sprinklers so let’s look closer into their differences and I’ll try to explain when one type of sprinkler may be better suited than the other for various common situations.
The Main Differences Between Impact & Gear Driven Sprinklers
Impact sprinklers are more basic between the two types even though they look somewhat complicated. They move due to the momentum and force created by the stream of water flowing through the head. The water moves an arm that’s which is what cases the water pattern and the impact of that arm creates the rotation of the head while it’s in use. It’s basic physics but it looks complicated.
The water impact simply makes the sprinkler head rotate across the desired area of the lawn; this causes the spray pattern to become very predictable and consistent, although it can also look and feel a bit unsteady due to the method of motion.
The arc pattern for impact sprinklers can usually be set anywhere up to 360 degrees however there are usually lower limitations on the arc size which vary from model to model. 22.5 degrees is a common lower threshold. This versatility usually allows you to cover most of (or all of) a given section of your lawn or yard.
As for spray distance, most impact sprinklers have a spray radius ranging anywhere from 20 to 150 feet depending on how much the water is restricted and how high the water pressure is.
Impact sprinklers are known to be a little noisy due to their method of motion and may require regular maintenance as a result. In addition, impact sprinklers use a little bit more water than gear drive sprinklers, due to the extra water required to make them move across their arcs. This can be good or bad depending on the terrain; certain ground types need a lot of water all the time and will benefit, but slopes or places with a lot of clay will suffer beneath such a heavy torrent.
Gear drive sprinklers are a bit more complicated and sometimes more expensive. It’s also hard to tell how they work since all the gears are hidden from plain sight.
For instance, if you compared the price on this top of the line wheeled impact sprinkler to this sled based gear driven sprinkler you’d see that although the price is similar there are many more options to choose from in the impact style making them a better overall value… also you’d see that customer reviews are typically higher for the best quality impact sprinklers in comparison to geared models.
The gear drive sprinklers use an internal mechanism (a gear) instead of an arm to move the sprinkler through its watering arc. This allows the sprinklers to move without as much noise or “shaky” motion that is typical of impact sprinkler heads. Gear drive sprinklers can also be quite reliable and consistent.
Gear drive sprinklers usually have an enclosed body design that makes it so that less maintenance is required; dirt and debris will get inside the sprinkler less frequently than an impact sprinkler. Gear driven sprinklers usually have an arc between 40 and 360 degrees and a range between 18 and 55 feet.
It’s more difficult to find gear driven sprinklers in general and especially in variable types. Finding sprinklers of this type is more difficult because of their relative newness when compared to the staple that is the impact sprinkler. As time passes, gear driven sprinklers may become more common and easier to find in greater variety.
How They Work
How Impact Sprinklers Work
The impact sprinkler is the typical sprinkler that you hear going “chk-chk-chk” which is the sound generated by the impact hammer hitting the back plate. They may be referred to as impact rotors as well but this is not common.
These sprinklers are designed to shoot out a large stream of water. Due to pressure imparted by the water stream they will trigger the hammer to turn into a spring allowing water to shoot out of the sprinkler head. The spring then sends the hammer back to the stream casing an impact which slightly turns the sprinkler head. The stream of water then pushes the hammer yet again causing the cycle to repeat over and over.
Because the stream of water is not restricted the coverage area can be quite large. In fact impact sprinklers are well known for their good coverage of large areas. If you are managing a big backyard you can sometimes get away with using a single impact sprinkler that you move occasionally between one or two locations. You can also efficiently water a large area using an impact sprinkler and a basic garden hose.
These sprinklers can even be adjusted to control the path and the distance to control your water usage.
Impact sprinklers come on a variety of different bases. The tripod, spike, and flat rectangle base. I find the flat rectangle base and the tripod base end up being the best base for an impact sprinkler for a homeowner that is going to be moving the sprinkler around the yard. If you can install the spike styles into the couple of locations you need to create zones that completely cover your grass that is the best way to use impact sprinklers so you don’t have to adjust the range and arc after you get it set for the location. Move the hose or use a splitter and run a garden hose to each of your zones during the months of the year that you need to irrigate the most.
Impact Sprinkler Pros
- Cover Large Areas – Impact sprinklers can provide a high output of water allowing you to adequately soak your lawn during the dry months.
- Affordable – There are many different models available, but due to their simple classic design even lower end units will work well for most homeowners.
- Well Water/ Hard Water – Impact sprinklers can last longer with hard water due to the limited number of parts and the simple sprinkler head designs.
- Maintenance – The simple designs make these easy to conduct maintenance on as needed and keep them well tuned for your needs.
Impact Sprinkler Cons
- Low Water Pressure Situations – Impact sprinklers require good solid water pressure in order to work effectively and create the nice arc pattern and water coverage that you expect from an impact sprinkler and low water pressure makes this very difficult.
Make sure to see this post to see some of my recommendations for low water pressure impact sprinklers.
How Gear Drive Rotary Sprinklers Work
Rotating sprinklers or rotor sprinklers are also referred to as gear driven rotors or rotary nozzles. The sprinklers are commonly found in the pop-up irrigation systems prevalent in many North American lawns.
Rotary nozzles are a type of spray head that is very efficient compared to other pop up irrigation spray heads. A rotary nozzle typically has a radius between 15 and 40 feet depending on the brand / product and your water pressure and can usually cover anywhere from 15-360 degrees around depending on the nozzle you install.
Many rotor sprinklers come as the single black tube looking sprinklers that fit into a pop-up irrigation system. These pop-up rotor sprinklers come in a myriad of models so make sure and read the details closely so that you understand the range, radius, and the inlet size for the sprinkler head.
You don’t have to get them as popup sprinklers though. There are also many options for these designed to be connected to the end of a garden hose and staked into the ground while they are in use.
By selecting the right distance nozzle and the desired spray pattern it can be possible to fine tune your watering much more-so than you could with an impact sprinkler system to avoid watering concrete paths, fences, cars, neighboring properties, or any other undesirable area which can help significantly in conserving water.
Rotating Sprinkler Pros
- Better Radius – A gear driven rotor sprinklers best quality is the better radius and, in some models, better distance and better spray distribution.
- More Efficient – Many rotary sprinklers will be more efficient than other forms. However, with all irrigation selecting the right head with the distance and arc that it provides is going to determine how efficient your watering ultimately is.
- Low Water Pressure – If your house water pressure is less than 40PSI than rotary sprinklers are the right choice.
Rotating Sprinkler Cons
- Can Sink or Tilt – If the rotor sprinkler in a pop-up system gets sunk or tilted it will overwater close to the head and not water at all in the further areas for the arc leaving dry patches.
- Servicing System –Depending on the problem but a break in the irrigation system can be a real pain to get fixed.
What Sprinkler Types Conserves Water Best
A well-tuned irrigation system with rotary nozzles will likely be very efficient in the water that is used to maintain a lush green lawn. It is worth the time and investment to have a professional help you install and fine tune an irrigation system, but even doing it yourself is very doable. An Impact sprinkler system can be adjusted to be pretty good, but do the high flow of water to work effectively if you do not have a timer set up or watch your clock it is very easy to overwater and use up a lot really quickly.
What Sprinkler Type Provides the Best Coverage
It used to be no question impact sprinklers had the best coverage but, rotor sprinklers are getting better and better every year and there are many models that have all the distance that you ever need to cover large areas. A similar size gear driven rotor is now capable of being better than an impact sprinkler due to a bigger radius and ability to cover more distance.
However, if you are most concerned with distance then absolutely go for an impact sprinkler – even better check out these impact sprinklers mounted on tripod bases, they will offer you the most coverage hand-down.
My Recommendation Impact Sprinkler vs Rotor Sprinklers
If you can set up a complete irrigation system for your lawns than rotor sprinklers are the way to go. They have the most overall control and the higher end options can outmatch any traditional impact sprinkler. A rotor sprinkler system is very efficient and conserves water while allowing you to keep a deep green grass all summer long.
Homeowners that are less focused on having the most perfect lawn or not ready to install a complete irrigation system just for nice grass can keep a healthy lawn all summer with a quality garden hose and impact sprinkler. Using the sprinkler that is on a stake will allow you to move it around the yard so you can break the lawn up into a couple of zones and make sure you have no dead spots. The impact sprinklers will lay down a large volume of water in a short period of time so it is possible to water your whole yard relatively quickly even if you need to manually move the garden hose and sprinkler once or twice to the other zones.
Both sprinkler heads will get the job done and you really need to just decide what type of watering do you want to do manual or automated. The price of rotor nozzles has come down significantly and all of the components for an irrigation system are easily available online, so with a little planning upgrading your watering plans to include a real irrigation system with a controller and rotor nozzles may be the right long term plan for your house.