The Milwaukee 3019-21WS M18 4-Gallon Water Supply Kit w/ SWITCH TANK is a battery-powered water supply system built for concrete cutting and coring. This is a cordless water supply kit designed for wet cutting, coring, and concrete dust management. Model Number: 3019-21WS. If you need a dependable way to feed water to your concrete cutting setup without stopping to pump by hand, this kit is the right kind of solution.

What makes this unit matter on the job is control. It delivers instant, constant, and adjustable pressure up to 60 PSI, with a 5-mode regulator that adjusts output from 20 to 60 PSI. That gives you a usable range for different tools and different cutting conditions, instead of a one-setting system that is either too weak or wasting water. For concrete cutting and coring, steady water delivery helps with dust suppression, blade cooling, and cleaner operation.

The SWITCH TANK design is the big story here. Milwaukee separates the powered base from the tank assembly, so the motor, battery compartment, and REDLINK electronics stay with the base while the tank assembly handles the pump, hose, and coupler. In real use, that means you can add, replace, and interchange tank assemblies instead of treating the whole unit like a one-piece setup. That is more flexible for crews that want one powered base and multiple application-specific tanks.

The 4-gallon tank is paired with a dual diaphragm pump for durability and longer pump life. Milwaukee also built in the little things that actually help on a muddy or dusty site: a wide-mouth opening for easier filling, a strainer to help keep debris out of the tank, and a premium adjustable harness with a carry handle for transport and storage. At 18.9 lb, it is not a featherweight, but it is meant to be carried as a jobsite tool, not babied like a shop accessory.

This kit is part of the M18 battery platform, so it runs on Milwaukee M18 batteries and ships with an included M18 REDLITHIUM XC battery and an M18/M12 multi-voltage charger. Milwaukee states runtime of up to 40 tanks per charge with the included battery configuration listed in the product data. If you are already on M18, that matters because you are not buying into a one-off battery system just to solve a water delivery problem.

For jobsite compliance and practicality, this unit is specifically called out as OSHA Table 1 compliant when used for concrete cutting and coring. Milwaukee also notes compatibility with pesticide sprayer tank assemblies in the SWITCH TANK line, which shows the value of the shared powered base concept. It is also shown as compatible with Milwaukee MX FUEL cut-off saw applications in the provided product imagery, making it a strong fit for concrete crews who need cordless mobility around the cut area.

Who should buy it? Concrete contractors, masonry crews, utility installers, and general contractors doing frequent slab cutting or coring will get the most out of it. It is also a smart pick for crews that move around active jobsites and do not want to drag a manual pump sprayer or unreliable improvised water setup behind them. If your work calls for controlled water delivery and fast setup, this is a purpose-built answer instead of a workaround.

Skip the pump-up bottle and use the right setup

The Milwaukee 3019-21WS M18 4-Gallon Water Supply Kit w/ SWITCH TANK makes a lot of sense for concrete crews that need cordless water delivery with real control and less fooling around.

• Who it's for: Concrete cutters, coring crews, masonry contractors, and general contractors who need portable wet cutting support on active jobsites.
• Why it stands out: The SWITCH TANK platform is the smart part. You get constant pressure, no manual pumping, and the ability to swap tank assemblies instead of buying a separate powered unit for every application.
• Worth knowing: This is a specialized jobsite tool, not a general-purpose sprayer. If you are not doing concrete work or another application that benefits from controlled pressurized water delivery, it is probably more system than you need.

• What kind of tool is this? It is a cordless 4-gallon water supply kit designed for concrete cutting and coring.
• How much pressure does it deliver? The system delivers adjustable pressure from 20 to 60 PSI, with a maximum of 60 PSI.
• Is it part of the Milwaukee M18 system? Yes. It runs on the Milwaukee M18 battery platform.
• Can the powered base be used with other SWITCH TANK assemblies? Yes. Milwaukee states the powered base is compatible with SWITCH TANK assemblies, including the 4-Gallon Sprayer Tank Assembly w/ SWITCH TANK.