Question:
I have a rainbow vacuum cleaner, the one with the water tank filter, cant find out if you can suck up water.?

Answer: Does the vacume tank have a float? If so you can use it as a wet vac. The float will not let water into the motor which would ruin it. For wet use you should use a float, for dry use you should use the filter. Like the float keeping water out, the filter will keep dust, etc. out of the motor and protect it.You can ruin the motor if you suck up more water than the tank can handle. You need an air barrier above the water to the vacuum. The vacuum air goes through the motor. The Rainbow keeps the water out of the motor by the reverse impeller in the tank. It spins so fast that the water cannot get through but allows the lighter air through. However, if the water gets too high the air barrier is gone and the all bets are off. The water will enter the motor and burn it out. Been there. Used to have one and ruined it doing that very thing trying to clear water from a sink. Didn't know about plungers at that time.