Leak help

[streetneons]

I live in south florida, house built in 2005. I had a plumber come out for $300.00 to tell me why water is coming in the master bedroom. hours later after checking he told me I had negative grade around house and rain water is getting under slab. I had a hard time believing that since we did not have rain in weeks. So I started to notice a trend when water would come in, when I would run the dishwasher... which the kitchen is on the other side of the wall. After 15-20 minutes water would come up... so I stopped using it for a week, tried again and it would leak. I pulled the front panel and ran a cycle and did not see any signs of leaking from the back underneath. If the dishwasher shares plumbing from the sink I believe wouldn't it leak if I run the sink a long time, which I tried for about 40 minutes on hot, or cold and nothing from the sink and leaking. I do not want to keep paying companies $300 just to tell me try this or try that, or even worse tell me I have a slab leak spend 2k and still not fix the issue and no recourse since all a plumber really has to say is yeah it was leaking, now its a new leak you need a re-pipe. Not saying its common but I could easily see that happening. Any ideas on what I should try.

 

[johnjh2o]

The first thing you need to do is determine if it's a water line or waste that's leaking. Turn off the main water supply valve. Don't use any water for 10 min. or more. Then turn the main back on. If you hear water moving through the main when you turn it on chances are you have a leak in the water lines. You can also check your water meter. Most have what we call leak detectors. It's a small triangle in the center of the meter. If that moves when you're not using the water there is a water leak.
Just where do you see water coming up?

 

[streetneons]

I am on well water, so I do not have a box to look at. I have stopped using the machine for about 3 months now and no water in the bedroom. As for the leak, its in the corner of the room where the wall is shared with the kitchen. There is a hairline crack that was about 2 feet long and water was coming up from that crack it appears, but being so close to the wall its hard to say for sure.

 

[johnjh2o]

Being on well water you must have a valve on the house side of the pressure tank you can use.