DeWalt 4 gal. Cordless Backpack Sprayer

Why I reached for a cordless backpack sprayer

I’ve used just about every flavor of pump-up and manual backpack sprayer over the years, and I finally wanted one thing: consistency. No more cadence of pumping and spraying, no more pressure drop-off while walking fence lines. I picked up the DeWalt cordless backpack sprayer to see if a battery-driven pump and adjustable flow control could give me even coverage for fertilizing, weed control, and perimeter pest treatments without wearing me out.

Build, fit, and comfort

The first impression is that this is built like a tool, not a toy. The tank is thick HDPE with a wide, secure cap that makes filling and adding dye or surfactants far less messy. The stainless-steel wand is a legitimate upgrade over the usual poly tubes—rigid, precise, and confidence-inspiring when you’re brushing past shrubs or loading in a truck.

The harness is better than most consumer sprayers I’ve strapped on. The padded shoulder straps are broad, and the hip belt actually transfers weight off your shoulders when you cinch it properly. With four gallons on board, you’re wearing roughly 35–40 pounds. That’s heavy, and no amount of padding changes physics, but the harness makes longer sessions realistic. If you’re smaller-framed or working on slopes, two to three gallons at a time is the sweet spot.

The battery compartment sits in a shrouded, water-resistant pocket with a positive latch. I used it in a light mist and during dewy mornings with no issues.

Controls and pressure management

The Variflo dial is the standout feature. The knob sits on the left side where you can reach it mid-pass, and the sprayer responds quickly. Dial it down for a gentle fan when you’re around ornamentals and bump it up for fence lines or jetting into cracks for pests. Consistent pressure is the whole reason to go cordless, and this sprayer delivers that in a way hand pumps simply can’t.

Noise is impressively low. The pump hums more than it buzzes—quiet enough that you can hear your pattern and the surroundings, which matters on residential sites.

Wand, nozzles, and spray quality

The included nozzles cover the bases: an adjustable brass cone, several fan options for high/low volume and width, a foaming nozzle, and a jet. The brass cone, in particular, gives a clean, predictable cone without spitting. The fan tips put down uniform sheets useful for pre-emergent applications along driveways.

The stainless wand hits a nice length—long enough for reach without getting unwieldy. There’s a nickel-plated swivel at the hose-to-wand interface that helps keep the hose from fighting you as you change angles. The wand’s shutoff has a lock-on that’s glove-friendly. It’s functional, though the trigger feel is a bit mushy compared to some pro-grade valves. I didn’t experience dribble at the tip when releasing the trigger; the system closes cleanly.

Hose and ergonomics: good and not so good

The hose is reinforced and resists kinks, which is great. The trade-off is stiffness. It has more “memory” than I’d like, and it can tug the wand as you walk. At 50 inches, it also feels a touch short when the tank is full and riding high on your back; a longer, slightly more supple hose would increase working comfort and reduce stress on fittings. The swivel helps, but I’d love to see a ball-swivel at the handle and an extra foot of length.

I did notice a light weep at the lower hose connection after a few tanks. Reseating the fitting and ensuring the clamp was properly aligned solved it, but this is a connection worth inspecting during clean-out. A drop of water at your hip isn’t the end of the world; a drop of chemical is unacceptable.

Priming and startup behavior

Out of the box, my unit self-primed after filling and venting the cap. After sitting idle for a few weeks, it needed help to purge air once. Tilting the unit forward, setting the dial high, and running the trigger got it moving within seconds. Ideally, a sprayer at this price should prime itself every time without user tricks. Once it’s moving fluid, it stays consistent, but the initial pull can be finicky after storage.

Filtration and clog resistance

Debris is the enemy of smooth spraying, so I like the triple filtration scheme: inlet, in-line, and handle screens. With dyed pre-emergent and a foaming agent, I didn’t encounter clogs at the nozzle, and the screens captured the expected flecks during cleaning. Rinse the tank promptly after use and clean the screens; that regimen keeps the system performing.

The Viton seals are appropriate for harsher chemicals. I ran typical lawn herbicides and permethrin-based mixes with no swelling or stiffness—just rinse and flush as you should with any sprayer.

Battery platform and runtime

Running on DeWalt 20V Max packs is a practical advantage. I used a 5.0Ah pack and easily cleared multiple gallons per session with plenty of charge left. The pump only runs when you spray, and it shuts off instantly when you release the trigger, so runtime stretches much longer than tools with constant draw. If you already own DeWalt batteries, the economics make sense, and the travel weight is lighter without a gas engine or separate battery pack.

Maintenance and parts

Cleanup is straightforward thanks to the wide cap and accessible screens. The water-resistant battery bay keeps electronics out of the rinse zone, and the shroud prevents errant splashes.

Where this package could be better is parts clarity. Consumables like hoses, clamps, shutoff valves, and seals should be easy to source by part number. I found the common wear items, but not everything is as plug-and-play as I’d expect from a major brand. If you plan on heavy commercial use, confirm availability of the specific hose and valve parts you prefer.

Field use results

• Lawn herbicides: With the low-volume fan tip and mid dial setting, I got an even, controllable sheet with minimal drift. The consistent pressure keeps application rates honest.
• Perimeter pest control: The cone nozzle at higher pressure lets you reach soffits and eaves cleanly. The jet tip is useful for cracks but easy to overuse—dial back and shorten burst times.
• Fertilizers and surfactants: No foaming eruptions out the cap, and the foam nozzle lays down a visible trail on hardscapes for reference.

Fatigue is lower than with manual sprayers simply because the pump does the work, but don’t underestimate the weight when fully loaded. Use the hip belt and keep the load under four gallons when working longer stretches.

What I’d change

• Add a longer, more flexible hose and a true ball-swivel at the handle.
• Improve self-priming after storage so it always pulls without intervention.
• Tighten up the shutoff feel; less travel and a crisper valve would be welcome.
• Make wear parts and hose assemblies easier to identify and order.

The bottom line

The DeWalt cordless backpack sprayer delivers what matters most in the field: consistent pressure, quiet operation, and a genuinely useful range of spray patterns. The harness and hip belt make the weight manageable, the stainless wand and Viton seals inspire confidence with tougher mixes, and the water-resistant battery compartment keeps the electrics out of trouble. The Variflo dial is not a gimmick—it’s the difference between fighting drift and getting clean edges.

It’s not perfect. The hose is stiffer and shorter than I’d like, priming after downtime can be temperamental, and parts sourcing could be clearer. Those drawbacks are real, but for my use—regular lawn care, periodic pest rounds, and small commercial jobs—the strengths far outweigh the quirks.

Recommendation: I recommend this sprayer, especially if you’re already on the DeWalt 20V platform and value pressure consistency and ergonomics over absolute lightness. If you need a featherweight rig or demand long, ultra-flexible hoses and pro-grade shutoff feel out of the box, you might look at higher-end commercial units. For most property owners and many pros, this strikes a smart balance of build quality, runtime, and spray control.