I have central air in my house. Last night I noticed water outside a kitchen window coming from a pipe. I am assuming that this was a overflow pipe from the air conditioner. I've looked in the top of the pipes next to the unit inside and noticed water inside the pipe. Is there supposed to be water visible in the pipe? I've been told to pour about a cup of bleach in each pipe once in a while to kill anything growing in it. Is bleach heavier than water? If I pour the bleach in the pipe will it flow through the water and out the other end or will it fill the pipe sitting on top of the water then overflow?