Piston vs Diaphragm Backpack Sprayer: Choosing The Right One

Have you been looking for a backpack sprayer for your yard or garden? With so many backpack sprayers to choose from, selecting one for your needs can be confusing and stressful.

Most landscapers and gardeners use diaphragm and piston backpack sprayers. Though they are both effective and work well, they function differently and have their own pros and cons.

Let’s take a closer look at both sprayers types to determine the best choice for you?

What Is the Difference Between a Diaphragm and Piston Backpack Sprayer?

Diaphragm and piston backpack sprayers technically have the same use. The main difference between them is the kind of pump they use. The diaphragm backpack sprayer relies on a diaphragm pump, while the piston backpack sprayer has a piston pump.

This fundamental difference provides each with different strengths and weaknesses. Let’s learn more about these two sprayers in detail to help you decide what kind of sprayer is right for you.

What is a Piston Backpack Sprayer?

A piston backpack sprayer is used for a variety of agricultural and horticultural purposes. They’re typically used for spraying pesticides and fertilizers in small orchards, lawns, and home gardens.

Piston backpack sprayers rely on piston pumps that generate considerable force for each spray. Piston backpack sprayers are generally more affordable and have simpler mechanisms that make them easy to fix.

Piston Backpack Sprayer

Unfortunately, piston sprayers aren’t as durable and chemically resistant as diaphragm backpack sprayers. In terms of popularity, piston pump sprayers have the edge over diaphragm backpack sprayers.


Piston pumps generally create higher pressure levels than diaphragm pumps with a maximum of 6 bars of pressure. This means that the droplet size produced by pistons pumps is smaller and travels longer distances.

This makes piston backpack sprayers a better option for spraying trees or shrubs since they allow droplets to reach plants that are farther away and harder to reach.


As the name suggests, both sprayers can be strapped to your back to make them easier to use and carry around. The main difference is the type of pump that these sprayers contain.

The pump inside a piston sprayer has a cylindrical housing that creates a spray whenever the piston moves in an up and down motion.

Resistance To Chemicals

While piston backpack sprayers are able to launch droplets over a greater distance, they are not suitable for syrupy, gritty, and corrosive liquids. They should also never be used with bleach solutions or wettable powders. These substances can permanently damage your pump.

Additionally, piston backpack sprayers aren’t completely sealed, so you may come into contact with dangerous chemicals if you use them with your sprayer.

Repair And Maintenance

Repairing and maintaining a piston pump is a breeze. All you need to do is remove a few screws, and you can get down to business.

Best Use Of Piston Pumps

The characteristics of piston pumps make them ideal for low-viscosity spray liquids like insecticides and herbicides.

What is a Diaphragm Backpack Sprayer?

Like the piston sprayer we’ve just covered, a diaphragm backpack sprayer is also used for agricultural and horticultural purposes. Could a diaphragm backpack sprayer be better for you? Let’s find out.

Diaphragm Backpack Sprayer


These sprayers contain flat diaphragms that are tightly held down by screws. A diaphragm sprayer functions in the same way as the one that sits inside our chests in the sense that they contract and relax to produce a spray.

Diaphragm pumps are more durable than piston pumps because there is no contact between the liquid you’re spraying and the cylindrical housing which contains the pump.


Unlike piston-based sprayers, diaphragm sprayers can only produce 4 bars or 60 pounds per square inch of pressure, considerably less than piston backpack sprayers. However, they are still extremely efficient, particularly when spraying plants that aren’t too far away. They are well suited for tasks like weed killing.

Resistance To Chemicals

As previously mentioned, piston pumps feature closed systems where the pumping mechanism has no contact with the cylinder wall. This means that the diaphragm pump is more durable and offers a higher level of chemical resistance. Wettable powders, bleach solutions, and corrosive chemicals can be safely used with diaphragm sprayers.

Repair and Maintenance

While piston pumps have only two screws, diaphragm sprayers have 12. Their closed designs make diaphragm pumps harder to maintain and repair since accessing the diaphragm is more challenging to access and more time-consuming.

Best Use Of Piston Pumps

Since their sprays don’t travel as far, diaphragm backpack sprayers should be used up close. They are effective for areas that require corrosive and abrasive solutions since the pump doesn’t come into contact with the liquid being sprayed.

Choosing The Right One

Both sprayers are equally beneficial as long as they’re used for the right purposes. Certain scenarios require piston sprayers, while others demand a diaphragm sprayer.

If you need to access hard-to-reach areas with less abrasive chemicals, piston backpack sprayers are your best option since they have stronger sprays that travel farther.

If you need to spray corrosive or dangerous chemicals within areas that aren’t that far away, diaphragm sprayers are your best bet since they provide more control over the spray. Their closed systems also help keep harmful chemicals away from you while keeping the pumping mechanisms within them safe.

Considerations Before Purchasing Backpack Sprayers

Now that we know how to distinguish piston backpack sprayers from diaphragm backpack sprayers let’s look at important aspects that will help you decide between products.

Tank Materials

Since sprayers are often exposed to abrasive or corrosive materials, look for heavy-duty and durable tanks. Try purchasing tanks that have UV and other corrosion-resistant substances.

Tank Size

Look for a tank with a large capacity for most tasks, so you don’t have to keep refilling it. Large tanks are also less likely to have spillovers when refilling. However, be careful that you don’t purchase a tank that’s too large because it will add unnecessary weight to your back.


Look at the nozzles included with your sprayer. Ensure that the tank you buy comes with replaceable nozzles because you might require different kinds.


As mentioned earlier, backpack sprayers often entail working with corrosive and dangerous chemicals. Therefore, you should check if the backpack you’re looking to buy comes with safety features like locks and shutoff valves.

Picking Out the Perfect Backpack Sprayer

Not all sprayers are created equal. While they’re ultimately used for the same purpose, each tank has different features to match various needs. Now that you know how to pick one out to suit your purposes, you can confidently find the perfect backpack sprayer for you.