Model WD1851


  • 6.5 Peak HP Motor – Powerful suction picks up about 1 gallon of water per second
  • Scroll Noise Reduction® is a patented feature that provides quiet operation by precisely controlling the flow of air through the vac
  • Sturdy Cart, Push Handle, & Large Rear Wheels act together allowing the vac to travel easily up & down steps and across rough terrain
  • Quick Release Accessory Storage Bag keeps accessories close at hand but is quickly removable to make emptying debris from drum quick and easy
  • 2-Piece Drum Provides improved, more rugged construction to meet the higher demands found on the job site
  • 3-layer Fine Dust Filter captures fine dust particles such as dry wall dust
  • 7' Dual-Flex® Locking Hose resists collapsing and adds 180˚ flexibility at both hose ends. Hose locks onto vac for uninterrupted cleaning
  • Large Carry Handle allows easy lifting of vac into service vehicle
  • Long 20’ Cord wraps neatly around carry handle
  • Powerful exhaust airstream can be directed through the vac hose to blow debris from garages, decks, and sidewalks


Drum Size 16 Gallons (US)
Cord Length 20’
U.L. Listed Yes
Replacement Filters VF3502, VF5000, VF6000, VF7000
Accessory Size 2-1/2"
Shipping Weight 32.8 lbs.
Net Weight 28.2 lbs.


Peak HP 6.5
Air Watts 306
Voltage 120
CFM 203
Amps 12.0

Ordering Information

Catalog Number Model No. Description Weight
lb. kg
31693 WD1851  16 Gallon Contractor Wet/Dry Vac  32.8  14.90 

Rated 4.8 out of 5 by 5 reviewers.
Rated 5 out of 5 by better than the rest I use the shop vac to suck out grease traps ,open sinks, get toys out of toilets, open tub lines .This product has been thoroughly field tested. Passed with flying colors. March 30, 2014
Rated 5 out of 5 by Have owned many of these for Flooring I have had to use these for Flooring, and i must say, they do not disappoint. I never had one fail on me And if i did, its because someone did not clean out the filter. And that usually takes YEARS. i only had one die on me, and will be seeing how the process is handled for Warranties. I will keep you updated. January 27, 2014
Rated 4 out of 5 by Missing one feature Before even trying out the unit, which based on other RIDGID tools, will be outstanding, I found one great feature and one missing one. The great feature is the hose attachment points on top of the rear wheel shaft assembly. Specifically made for the hose to wrap around and secure, it is very innovative. However, using the attachment points for the hose does not provide any location to store/carry the 2 extension wands. I notice on other units, you have connection pieces above all of the wheels but nothing above the front castor wheels on this model. So one either has to store the wands where the hose should go and wrap the hose, which is not very good for the hose, or store the hose and jerry rig some way to store/carry the wands. December 28, 2013
Rated 5 out of 5 by Simply the best shop vacuums made. I've owned one of these for several years now, and it is simply the best vacuum I've ever used. It is also so quiet that you can hold a normal conversation while standing right next to it while it is running. I also own, and or have used shop vacs made by all of the other major manufacturers, and none of them even come close to the performance of the Ridgid vacuums. I liked mine so much that I have just bought another one, this one with the removable blower. I've also recommended these vacuums to my friends, and they have been just as happy with them as I am. December 2, 2013
Rated 5 out of 5 by Just the right size for our needs Easy to assemble. Crews likes the power. Great job on water pickup. Right size for our needs. Easy to empty at slop sinks. Cant beat life time warranty !!!!!! October 21, 2013
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1 Question | 2 Answers

Product Q&A

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2 answers


If a airwatts are 0.117354 * (CFM) * (inches water), then do I calculate correctly that this model no. WD1851 will lift water 12.8 inches high?

306 watts * (1/0.117354) * (1/203 CFM) = 12.8 inches of water

I feel like that number is way too low - I'm sure your product lifts water more than 1 foot high! I may have the calculation wrong or the pressure may be specified another way. What do the units of "G/h" mean?

Besides, it seems like an odd coincidence that this is almost exactly the inches for model WD4070 when the WD4070 is rated 5.0 peak HP and the model on this page is rated 6.5 peak HP.

Thank you for the help.
3 months, 4 weeks ago
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Indiana, USA
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According to our Product Manager, You need to first think of CFM and Inches of water lift in inches as two different and inversely related measurements. To maximize CFM, you need a wide open path with as little resistance as possible to move as much air as possible. To maximize inches of lift (or better recognize or measure) that flow of air needs to be restricted, or blocked. So to assume that our machines generate 203 CFM and 49 inches of lift at the same time is a miss-conception. The calculation you completed was “at 306 air watts and 203 CFM, what are the inches of lift being produced”… and the answer is 12.8. Essentially, you’ve identified the inches of lift at the rated max CFM and Air Watts. For example, if you solved for CFM at max inches (say 49) you get a really small CFM number, somewhere below .2 CFM. This is because at max inches (the hose is blocked) and there is “no” air moving through the hose.

We hope this helps. Have a good week ahead!

Thank you
3 months, 2 weeks ago
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Thank you, RIDGID! That really helped me understand how the pressure and CFM are related, and the calculation result of 12.8 inches makes sense now. I didn't realize the airwatts equation was NOT referring to "sealed" inches of water. Now I see why using sealed inches for calculating airwatts wouldn't make any sense.

You mentioned 49 inches a couple times. Is that the sealed lift this vacuum is rated for? If not, would you please share the max water lift rating?

Thank you again.
3 months, 2 weeks ago
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Indiana, USA
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