Pet water fountains can be classified based on various criteria, including:
    Type of Fountain: Pet water fountains can be classified based on the type of fountain, such as electric, battery-operated, or manual.
    Material: Pet water fountains can be classified based on the material they are made of, such as plastic, ceramic, stainless steel, or glass.
    Capacity: Pet water fountains can be classified based on their capacity, ranging from small fountains for single pets to large fountains for multiple pets or commercial use.
    Design: Pet water fountains can be classified based on their design, such as freestanding fountains, wall-mounted fountains, or tabletop fountains.
    Filtration system: Pet water fountains can also be classified based on the type of filtration system they use, such as charcoal or carbon filters, mechanical filters, or UV sterilization systems.
    Additional features: Pet water fountains can also be classified based on additional features they offer, such as adjustable water flow, automatic shut-off, or multiple water outlets.
Overall, the classification of pet water fountains can be based on the type of fountain, material, capacity, design, filtration system, and additional features. Choosing the right pet water fountain for a specific pet or application requires careful consideration of these factors, as well as the pet's size, drinking habits, and any health concerns.Meanwhile,The structure of pet water fountains can vary depending on the specific model and manufacturer, but most pet water fountains typically have the following components:
    Reservoir: The reservoir is the main container that holds the water and can vary in size and capacity. It is typically made of plastic, ceramic, stainless steel, or glass.
    Pump: The pump is the main component that circulates the water and is usually located at the bottom of the reservoir. It can be electric, battery-operated, or manual.
    Water filter: The water filter is an optional component that helps to purify the water and remove impurities. It can be a carbon filter, mechanical filter, or UV sterilization system.
    Water outlet: The water outlet is the opening where the water flows out of the fountain and into a bowl or basin for the pet to drink from. It can be a single or multiple outlet design.
    Power cord: The power cord is the electrical cord that connects the pump to an electrical outlet and can vary in length and design.
    Bowl or basin: The bowl or basin is the container where the water flows into for the pet to drink from. It can be made of plastic, ceramic, stainless steel, or other materials.
Overall, the structure of pet water fountains can vary, but they typically have a reservoir, pump, water filter, water outlet, power cord, and bowl or basin. Some models may have additional components, such as adjustable water flow, automatic shut-off, or multiple water outlets.