"Waterproof" and "Water resistant" are very common in our daily life, but some of unprofessional sales or consumers are confused and caused a bad purchase experience and misleading in result. Knowing the differences between the two is important for your comfort when your requirement is occurred. There is no good or bad between the two but the difference between the purpose of use and your acceptance of the price.
Water resistant boots are ideal for activities such as walking and gardening in light rain, snow or sleet -- any activity that doesn't involve submerging the foot for extended periods in water or snow. They are made with upper material that shed water because of their weave/fiber or because they have been treated. They are able to resist the penetration of water to some degree but not entirely.
Waterproof boots are specially constructed to protect your feet and lower legs from extended exposure to moisture, cold and harsh weather. Waterproof boots also protect you if you work in jobs where you're exposed to slippery floors or hazardous materials.They are impervious to water. Higher level waterproof shoes are typically made of PU or Thermoplastic Polyurethane (TPU) membrane. The membrane makes the shoes completely waterproof and cannot be penetrated by water so they are completely waterproof and not just water resistant.
Just as food labels are highly regulated, so is the sale of footwear that's marketed as water resistant or waterproof: The waterproof performance level of a waterproof work boot is tested on a dynamic (flexion) footwear water resistance machine. The waterproof safety boot is fixed onto a mechanical foot and set into a container of colored water to a defined water depth (approx. 20mm) above the work boot feather line. It is then flexed at a constant speed and angle, while the (potential) penetration of water into the waterproof work boot is reviewed at intervals.