There has been some white stuff appearing on my garage floor along what looks like a narrow wet path or stain about 8" wide and 9 ft long. I thought it might be the beginnings of mold, so I sprayed it with bleach n water which immediately disolved it, but it still comes back every morning. It just started about a couple of weeks ago. Here.s is a pic, does anyone know what it is? Thanks.
01:17PM | 12/03/13
it is probably efflorescence (not mold) caused by water vapor coming to the surface of the slab and leaving mineral deposits.
01:34PM | 12/03/13
To stop it from reoccurring, you will need to seal the garage floor or at least that section and try to find out why there may be water coming from underneath.
12:53PM | 12/04/13
If it was me, I'd be concerned that there may be a plumbing water leak or a natural spring beneath the slab. When you clean off the mold, is there a fine crack in the floor allowing the seep? Mold such as yours needs water to form. Unless you have a large dog urinating in the same place on the floor, I'm afraid you have a water issue below the floor.
First step would be to take a look at your meter shut off for your house water. You will see a small red or blue (most of the time) spinner on the dial. Stop all use of water in the house and view the spinner for at least 5 min.. If it moves, you have a plumbing leak, if not you may have a ground water issue.