The Milwaukee M18 Switch Tank Interchangeable Sprayer and Water System starts at a power base and connects to a tank designed for water, pesticide and concrete applications. It's an interesting concept powered by the M18 battery platform.
What's interesting about this system is the two areas it covers – concrete construction and landscaping. There are legitimate uses for both, and it's an interesting way to use one power base to expand in both industries.
The best part is that you are looking for a battery operated backpack sprayer. You can say goodbye to the days of manual expression.

This is a two-part system. The power base is where the battery connects and the motor runs. The tank assembly holds the pump, hoses, fittings and stores fluid. It might seem odd to separate the motor and pump, but that's why Milwaukee is able to get different flows for different applications.
This separation also means you can change tanks without worrying about cross-contamination. As a mason, put different sealants in different pots. As a gardener, have a different tank for each pesticide and herbicide.
Each kit comes with a 3.0Ah battery—enough to hold up to 12 tanks or 48 gallons of product. If you want longer run times, any Milwaukee M18 battery will fit in the battery compartment, including the 12.0Ah high output battery.

Milwaukee M18 Switch Tank Water Supply
In construction, the Switch Tank watering system is mainly for concrete cutting and drilling. It gives you adjustable pressure between 20 and 60 PSI with 5 adjustment settings.
The tank has a double diaphragm pump and a wide mouth with filter.

- Milwaukee 2820-21WS
- 20 – 60 PSI with 5 adjustment settings
- 0.16 – 1.13 GPM flow rate
- Uses up to 12 tanks per charge with 3.0 Ah battery
- Nitrile seals
- 10' Hose with Quick Connect
- including water nozzle
- 18.45 lbs including battery, power base and fuel tank
- 3-year power base warranty
- 1 year water tank assembly warranty
- $449 ($164 for the 49-16-28WS tank only)
Milwaukee M18 Switch Tank Concrete Sprayer
This one is for professionals working in concrete and is built similarly to a pesticide sprayer. You get the same 20 – 120 PSI adjustable pressure with 5 settings and a spray distance of 25 feet. There are Viton seals throughout the tank.
The main difference is traffic. You'll get 0.14 – 0.82 GPM from your concrete system compared to 0.10 – 0.51 per minute from a pesticide sprayer.

- Milwaukee 2820-21CS
- 20 – 120 PSI with 5 adjustment settings
- 0.14 – 0.82 GPM flow rate
- 25′ spray distance
- Uses up to 12 tanks per charge with 3.0 Ah battery
- Viton seals
- 4' hose with sprayer handle and wand
- Lock/Open Mechanism on Sprayer Handle
- Includes large diameter adjustable nozzles and flat nozzles
- 18.3 lbs including battery, power base and water tank
- 3-year power base warranty
- 1 year water tank assembly warranty
- $449 ($164 for the 49-16-28CS tank only)
Milwaukee M18 Switch Tank Insecticide Sprayer
The Switch Tank Pesticide Sprayer System has 5 adjustable pressure settings ranging from 20 to 120 PSI and a maximum spray distance of 25 feet. Lower flow rates are designed to give you more control over small areas.

The tank has the same dual diaphragm pump as the others, with Viton seals in critical areas and Nitrile seals elsewhere. It also has a wide opening with a filter.
- Milwaukee 2820-21PS
- 20 – 120 PSI with 5 adjustment settings
- 0.10 – 0.51 GPM flow rate
- 25′ spray distance
- Uses up to 12 tanks per charge with 3.0 Ah battery
- Viton seals in critical areas, Nitrile in other areas
- 4' hose with sprayer handle and wand
- Lock/Open Mechanism on Sprayer Handle
- Includes small diameter adjustable nozzles and flat nozzles
- 18.3 lbs including battery, power base and water tank
- 3-year power base warranty
- 1 year water tank assembly warranty
- $399 ($149 tank only 49-16-28PS or $299 bare tool 2820-20PS)
Using the Milwaukee Switch Tank System
Performance
We primarily enjoy the Switch Tank with the insecticide sprayer, and we base most of our impressions on its use. Concrete injectors have higher flow rates and are slightly different, but the experience is pretty much the same. Water supply is where significant changes are delivered. We haven't had a chance to use it in this capacity yet.
Having said that, it only takes a few minutes to get used to the power and flow adjustments. They are really easy to reach and operate.

Once you fill up the tank or replace it, the system may need to be primed – something it does automatically.
Reviewer's note: In general, you always want to add chemicals to water when dilution is required. With the Milwaukee Switch Tank, you don't have to do the typical "shake the tank" dance with your hand sprayer. Instead, just add the chemicals to a filled switch can, then use the stick to stir for a minute or so. You get a self-stimulating system that saves you time…and your arms. When done, put the lid back on.
Our pest control specialists use the Switch Tank as a temporary installation. He can save time by simply grabbing the tank instead of dragging out a long hose. He even fills it straight from a larger tank, no need to deal with mixing chemicals.

Once everything is properly mixed and ready to go, just find the flow rate that works for you and get to work!
The sprayer has a range of 25 feet, making it perfect for tackling just about anything on your tree. The system easily reaches the soffits of taller residential buildings and can cover large areas of ground quickly and easily.

switch tank
This wouldn't be a complete Milwaukee M18 Switch Tank review if we weren't actually talking about Switch Tanks! This is a very simple process. A clip on the front and a clip on the back secure the tank. Once loose, the tank lifts up and closes.
The two downward facing tabs on the back of each tank slide over the harness frame and hold it in place while you lock the clip down.

When you close the tank, notice the 3 metal connectors – two silver and one gold. Keep an eye out for these and wipe them down from time to time. If your pump isn't working and you know your battery is good, one of these connections probably needs cleaning.

ergonomics
Hand backpack sprayers have a weight range of 7-12 lbs. You'll notice the extra 6 lbs that come with the system – add 4 gallons of fluid to add weight (approximately 32 lbs).
The harness secures the tank near your back. It balances the weight well and gives you plenty of adjustability. I had no issues fitting it nicely into my 6'2" frame.

The shoulder straps include some padding, but it allows for more padding on your shoulders. It's a little uncomfortable in there, but certainly better than most backpack sprayers I've used. The hip belt seems to hold the weight well.
One of the things our resident pest control specialist Brian likes about this system is how easy it is to take apart for storage. He was able to store the fuel tank upright in the back of the truck and store the bed and harness in the front.

wand storage
The most obvious place to store your wand is in the center of the tank handle. You also get a side storage location against the frame handle, with a point just below it to hold the tip.

These are great, but it takes some practice to get the wand back in either position while wearing the Milwaukee Switch vest. If you look closely at the belt on the right side, you'll notice an elastic loop that allows you to slip your wand through it like a holster. This works well when you need to cover long distances and want to keep your hands free.
Wands are usually a problem. You can easily bend or break cheap ones. While it's definitely possible to break the ones that Milwaukee has to offer, they look pretty solid. They even include locks and locks on the handles.

we shouldn't say it but we will
Use Milwaukee M18 Switch Tank only with chemicals for which it is rated. Each tank is specifically designed for the environment and job they say it does. Different tanks have different seals depending on the chemicals that are intended to be used. The bleach has run out. Flammable liquid has escaped (you have batteries for power). Margaritas are out…wait, eh? In any case, you'll also want to make sure you rinse the tank thoroughly before adding any new chemicals to avoid cross-contamination or potential reactions.

It's clear that Milwaukee has put some thought into building a tough design. Remember, they want you to get the most life and value out of this tool.
Learn more on Milwaukee's website!