Am thirsty mum

Why is it that cats (and dogs) drink from the most horrid places? Murph has three dishes of water around the house but he still insists on drinking from other places.
Favourites are
1. the bath- he sits and watches you in the shower and as soon as you step out he is in like a shot and licks the bath! I guess its the soap he likes, on the up side I don't get soap rings however these are replaced by dirty cat paws, I have a whire bath! (sometimes)

2. the glass beside my bed. I always have a glass of water at night and have been woken to the sound of slurping and the sight of Murphs bum as he drinks from my glass!

3. the pond, well more a tub full of rank water which I keep trying to turn into a bog pond but the water keeps going horrid and kills the plants I put in it. I followed all the instruction have purchased a number of oxygenating palnts but have yet to get it to work. Still gives murph something to dring out of!