• One final note on waterproofing: sealing only the interior basement walls is not a viable option, as water can still seep in through cracks in the foundation, even if moisture does not appear in your basement's interior. Ironically, this solution might actually trap water in the foundation walls and do more harm than good.
  
  Remember to call the Department of Building Inspection at (415) 558-6088 to see if a permit is required for your project. Before digging, also look out for your own safety by calling PG&E at 1-800-227-2600 to make sure that you will not be disrupting any underground utility lines. You must contact PG&E at least two days before the start of your project.
  
  
• Another option for dealing with your basement water issues — and one to use in conjunction with any of the two mentioned above — is to control the flow of water outside your home:
  
  
• Observe how rain falls from your roof, downspouts and gutters. You will want to make sure that this drainage system is working properly and that water is channeled substantially away from your foundation.
  
  
• Check that there is no pooling water near the edge of the house, since this could seep into the basement. You may need to add additional drainage to your yard if cleaning or improving the gutter-downspout system cannot correct any standing water problems.
  
  
• Make sure that the ground slopes away from your foundation at all points. If not, you may need to add extra soil to create a substantial enough grade.