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Tank gallons are not the water you can pick up
Updated
The gallons in the title are the volume of the empty tank. Vacmaster's maker page says it directly: tank size refers to the actual tank volume and does not reflect the capacity available during operation. A float inside shuts off suction before water reaches the motor, so a wet pickup ends before the tank is full.
How the float works
Shop-Vac's FAQ describes it: once the water gets high enough in the tank, the float stops the air suctioning. The motor pitch rises and pickup stops. That is the vac protecting itself, not a fault. Empty the tank and carry on. No listing here says how many gallons its float allows, so we do not put a number on it.
What a full tank weighs
Water weighs about 8.34 pounds a gallon.
| Model | Tank | Water weight if filled to the listed size | Vac weight | Total | Drain port |
|---|---|---|---|---|---|
| CRAFTSMAN 16 gal | 16 gal | 133 lb | 26.0 lb | About 159 lb | Yes |
| Vacmaster 12 gal | 12 gal | 100 lb | 24.1 lb | About 124 lb | Yes |
| Vacmaster Beast 5 gal | 5 gal | 42 lb | 15.4 lb | About 57 lb | Not on the listing |
| DEWALT 6 gal | 6 gal | 50 lb | 14.77 lb | About 65 lb | Not on the listing |
| Stanley 6 gal | 6 gal | 50 lb | 13.4 lb | About 63 lb | Not on the listing |
| Vacmaster 5 gal steel | 5 gal | 42 lb | 11.66 lb | About 53 lb | Not on the listing |
| Armor All 2.5 gal | 2.5 gal | 21 lb | 10.99 lb | About 32 lb | Not on the listing |
- CRAFTSMAN 16 gal159 lb
- Vacmaster 12 gal124 lb
- Vacmaster Beast 5 gal57 lb
- DEWALT 6 gal65 lb
- Stanley 6 gal63 lb
- Vacmaster 5 gal steel53 lb
- Armor All 2.5 gal32 lb
The float keeps you under those totals, but the point stands. A 16 gallon vac near 159 pounds is not something to carry up basement stairs. That is what the drain port is for. Roll it to a floor drain or a door, open the drain, and let it run out. Both big picks here have one. The small vacs do not need one: 5 gallons of water is about 42 pounds.
Set up for water
- Take out the dry cartridge filter and any dust bag. The maker of Vacmaster says to remove dry filters and bags before vacuuming liquids.
- Fit the foam sleeve. Both Shop-Vac and Vacmaster's maker say foam is the filter for wet pickup.
- When you are done, the maker of Vacmaster says to remove the foam filter and let it dry completely before you fit a dry filter again.
Flooded basement: safety first
The CDC says that if you have standing water and can turn off the main power from a dry location, do that first, even if it delays cleaning. If you would have to step into standing water to reach the switch, it says to call an electrician. Once an electrician has determined it is safe to turn the power on, the CDC lists a wet/dry shop vacuum as one way to remove standing water, and says to wear rubber boots when running equipment in wet areas.
The EPA's flood cleanup guidance says to wear an N-95 respirator, goggles and gloves when you clean up, and warns that older homes may contain asbestos or lead. For deep water, a pump is the better tool. A shop vac is for the last inch and the puddles.
Run any listing through the peak HP calculator, match a vac to your job with the job checker, or compare all seven picks on the roundup page.