[updated] Home exterior water leak / concrete porch damage [scott1960] Options

New information: 1. We did have that unusual snow a couple of weeks ago. 2. I reposted (below) my original message with a CORRECTED LINK to pics that should work
In my next post, I'll list the action plan based on everyone's response so far.
________________________________________ REPOSTED... (PICTURE LINK AT BOTTOM FIXED). Hopefully someone can help me with this.
Moved into this house in Las Vegas about 3 years ago. Started noticing some discoloration & deterioration of the concrete porch. In the desert landscaped rocks near the porch, and along the house, there's about a 12 inch width of wetness. This also appears along my neighbor's house, as well as the wall on the other side of my house. The dirt under the rocks is moist to muddy. No area of bubbling water. My sprinkler drip Rainbird has been off at the controller for the past several weeks. I turned it on to water only about 3 times.
My questions: 1. Has anyone seen this before? 2. Any ideas on the cause? 3. Any recommendations on the type of professional I should contact to diagnose what's going on? 4. Any other steps I should take?
Pictures located here: http://www.philtwo3and4.com/index.html?1231454057152

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