Shower – How to prepare the shower walls for tiling to prevent mold and mildew

To remove surface mold I use a 4:1 mixture of water:bleach. Spray on liberally and allow to sit for about 15 minutes. Rinse with water and wipe clean.

If you need to use a brush to scrape off heavy deposits, I recommend brushing away from your face or preferably wear an appropriate mask and goggles. The mold spores are probably more dangerous than the bleach at that point, but neither one is fun.

Commercial cleaners such as Tilex tend to do a reasonably good job as well.

Whichever way you go, make sure that you give yourself adequate ventilation as the fumes may be quite strong.

As you've already noted that you need to take remedial action to prevent future growth, I'll just echo BMitch's comment that you should investigate if the mold has spread into the walls as hidden growth can be a future problem.

What you describe requires major plumbing work and can cause devastating damage to your home. Your landlord should be responsible for fixing this because with moisture leaking behind the walls like this then it can quickly create major property damage to his rental unit and unhealthy mold.

Your landlords refusal to fix this on his own is creating a health hazard for you, and in many countries and states there are laws that protect tenants and give them certain rights in a landlord-tenant relationship. One of these rights is the right to a safe and hazard free home, which means you can and should be able to bring suit against the landlord in the event where he refuses to fix a situation with the property that is creating a signficant health hazard for you and your family.

To get rid of the mildew, talk to your landlord and tell him to fix the leak immediately.