Check the manual for your exact vacuum. The old blanket rule that every shop-vac filter must come out for water is not safe to apply to every current model.
Why the advice sounds contradictory
Different wet/dry vacs use different filter systems. Current RIDGID information says it recommends a cartridge filter for wet/dry pickups and sells the VF7000 wet-application foam filter for high-volume liquid cleanup with debris on many 5-gallon-and-larger RIDGID vacs.
For a RIDGID WD1450 owner
RIDGID lists the WD1450 with a cartridge filter and shows the VF7000 as the optional wet filter in its product literature. That gives you a model-specific path instead of a generic internet rule.
What the wet filter is doing
RIDGID says the wet filter helps keep waterborne debris out of the blower wheel during heavy liquid pickup. That is different from using a fine-dust filter to catch drywall dust.
Do not use a dust collection bag for water
Collection bags are for appropriate dry pickup on models that support them. They are not water tanks.
Read the bag-vs-filter guide for dry cleanup.
Find the model number on the vac, then follow that model’s wet-pickup instructions. This is one of those jobs where a generic shortcut can be worse than spending one minute with the manual.
How to make the decision without guessing
- Find the vacuum model number.
- Open the wet-pickup section of that model’s manual.
- Check whether the standard cartridge filter stays on.
- Check whether the manufacturer offers or requires a wet filter for high-volume liquid pickup.
- Remove any disposable dry collection bag unless the manual specifically says otherwise.
Why a wet filter can be useful
Water often contains grit, pet hair, mud and other debris. A wet-application filter can keep that material away from the blower path without using a dry paper bag.
Dry the filter before going back to fine dust
A wet filter or damp cartridge and fine dry dust are a bad combination. Follow the cleaning and drying instructions before switching jobs.