Is it white? (cloudy) If so very much could be.
water change dude..you probably have high ammonia..
I agree had the same prob myself. Water from tap was 6ppm
I suggest to test tap and tank water first. If it's the tank. treat do a big waterchange after treatment. And use bio zyme or bio spira both work great for making a good biolodgical process.
If its the tap like mine buy a water filter from petsmart for 30 dollars. that will remove ammonia.