It is safe to leave a water fountain on all the time. Fountains are designed with a flow control valve that maintains the correct water pressure, so there is no need to turn them off and on. In fact, turning fountains off and on can actually damage the equipment. Always make sure the power cord is unplugged when not in use.

You can leave a water fountain on all the time, but it's not recommended. Water fountains can be left on all the time, but it's not recommended because they use a lot of electricity and can be expensive to operate. It's also important to note that water fountains should only be operated by people who are knowledgeable about electrical wiring and circuitry, as there is a risk of electrical shock if the fountain is not properly installed or maintained.