Water moisture coming through a concrete wall can create a white crystal deposit on the wall. This process is called efflorescence. It is caused by salts in the concrete that migrates to the surface along with the water. As the water evaporates the salt crystals are left. This is not a structural problem and will not cause any damage to your walls. It does indicate that your foundation is not draining properly and water is making its way into your home. It may be due to a failing drain system that should be investigated before it gets worse. Puget Sound Waterproofing can help you determine the extent of your problem and what should be done. Give us a call for a free consultation.