No matter what type of vacuum cleaner or floor sweeper that you use, the dust and dirt you collect should only be placed in the garbage. Do not dump the contents of your vaccum bag or chamber in any public places, including waterways, swales, or storm drains. Seemingly harmless debris is actually considered stormwater pollution and can be very damaging.
If your appliance is water-based, please do not pour the water and dirt down interior or exterior drains. Filter debris and place that in the garbage. The remaining water (with only small amounts of dust and dirt) can be flushed down a toilet.