Disposal of latex paint, as a liquid, is commonly part of the Household Hazardous Materials events, but Ann Hamilton for the Green Hills Regional Planning Commission, says as a solid, it can be thrown in your household trash.
Hamilton says to first verify you have latex paint.
If clean-up is with soap and water, allow it to dry and dispose of it in your trash.
Oil-based and other paints that are not cleaned up with soap and water need to be taken to a Household Hazardous Materials collection event for disposal.