I've been living in my home for 28 years. It's brick on a cement foundation built in 1985. I had a patio poured at the back door in 1986. There is a approx. 1/16 inch crack that I should have sealed where the patio meets the brick but I never did and it has never been a problem. For the last week water has been seeping from the crack in a couple of areas close to each other enough to saturate an area of approx 3 ft. x 7 ft. This area has been constantly wet for a week now. Dont know if this is related but about a month ago the water pressure in my shower slowly decreased, got new shower head and had fair pressure for about a week and now it seem to be decreasing again. Checked water meter and it shows no water leaking when no water is being used. The shower is on the opposite side of the leak, and the ground is not wet anywhere else around the house. Can someone please tell me what this is?
OK, the water must be coming from somewhere:
Water from a leak. If you've been checking your meter and don't think you have any leaks inside that's good, but it's possible there is a crack or break in service line upstream of your meter. This might actually explain reduced water pressure in the house. If you suspect this is the problem I would call your water company and have them take a look.
Rainwater. If the water appears only during and shortly after a storm, then you probably have a drainage problem. Make sure all gutters are directed away from the house. You might also look at grading near the house to make sure water will flow away from the house. Is the porch at the bottom of a slope towards the house?
Groundwater. I would be a little surprised if this were groundwater welling up, but it's not impossible. Have you had a very wet spring that would've raised the water table level? Or done any serious landscaping / excavation / compacting in your area?
Septic system. An unhappy septic system can cause water to well up, although probably not so close to the house or clear / odorless. Do you have a septic system?
(I wouldn't beat yourself up too much about not sealing that gap. If water is pooling from below I doubt a little sealant would hold it off for long.)