Backyard Fountain losing water only when pump is on
Help! My husband and I just bought our first house about two months ago and it came with a fountain in our backyard. We have loved it and It has been working fine until a couple of days ago. We were outside with some friends and the pump was on and the fountain was completely full and then about 20 minutes later, we look in the fountain and the water was noticeably lower. We have come to the conclusion that the water only gets extremely low when the pump is on.
When the pump is off, the water seems to stay in. We really don’t know anything about backyard fountains so I thought I’d come here first before we attempted to fix it ourselves and then screw something up. Any help or advice would be so greatly appreciated. We are just worried the water is leaking towards our house or somewhere else that could potentially cost us some money.
Thanks in advance!!!