Buzzing

I went out into the kitchen to find something to eat for lunch and was hearing this loud buzzing noise, like an electrical kind of buzzing, kind of like, oh, I don't know what it was kind of like but it was loud and very very annoying.

Is it coming from outside? No. The refrigerator? No. The ceiling fan? No. The air conditioner? No. Is the house getting ready to explode? It gets louder over on this side of the kitchen, so it's not the ceiling fan. If I move over by the refrigerator it's not as loud. Back to the other side of the kitchen. Louder and more annoying and it's giving me a freaking headache! What is it? It's driving me crazy!

Oh. It's the cats electric water fountain drinking bowl (yes, they are spoiled and have a special cat fountain to drink from). When the water gets low it usually makes a horrible metallic gurgling sound but this time it's making a horrible high pitched humming buzzing sound. Add more water. Buzzing stops. But I feel really stupid.