Moldy shower cault

My house is three years old. In my master bath we have an enclosed glass door square shower with one of those white plastic pans going up about three inches around the edge on the bottom and then the walls are tiled with basic 4inch tile. Last year the caulk between the edge of the pan and tile began to grow pink and green bacteria/mold (yuk!). I scraped it all out and did not use that shower for three days to let it dry out. I recaulked. Now a year later the mold is growing back, but only in one spot at least. I am worried water is getting behind there somehow. If so, how could I check that without removing the tile? I have to tile the bathroom floor this year, but re-doing the shower seems like a big job to prep (tiling it is the easy part). I would prefer not to have to recaulk the shower every year. Any suggestions on what to do about my mold problem?

 

Mold on the surface of the caulk does not mean water is getting behind the tiles. The only way I know to check for that is to inspect the flooring under the shower area if you have access.

The problem is usually because you may not have killed all of the existing mold and your shower has high humidity for too long. To remedy the first situation, after you remove the caulk, use a diluted bleach solution to kill all of the exisiting mold. Then buy the best caulk available. Search the web for caulking tips if you need to.

If you don't have a bathroom fan you may consider having one installed. I need to do this and I believe Fine Homebuilding and Family Handyman both had excellent articles on this recently although I have been told it's much easier to go out of the side of the house instead of through the roof (assuming you are DIY). You may also consider a timer switch on the fan that leaves the fan on for a while after turning off the light. I think most existing fans are undersized or noisy so you may want to make sure your is sized correctly or replace it- see the articles.