Yes, water can leak from under your dash. There are seams on the outside sides of the wall. You would have to remove some body panels to get to the seams.
This is what happened with my Honda civic. here are some instructions
Answers.com From Seam Under Corner of Dash
(Supersedes 92-050, dated May 15, 1995)
SYMPTOM
A water leak into the footwell from under the left or right corner of the dash.
PROBABLE CAUSE
Not enough sealer on the cowl side of the panel-to-bulkhead seam.
CORRECTIVE ACTION
Apply sealer to the seams where the side panel joins the bulkhead. Refer to section 20 of the appropriate Service Manual for removal and reinstallation of body components.
1. Look for a leak from the lower comers of the dashboard while an assistant runs water over the windshield and cowl. Confirm which side is leaking.
2. Remove the Answers.com arms and the cowl cover.
3. Remove the side sill, the inner fender, and the front fender from the side that is leaking.
4. Insert a scraping tool through the access holes, and remove all loose sealer. For better visibility, shine a flashlight through the holes.
5. Before you reseal the seams, clean them with a wax and grease remover such as Prepsol.
6. Apply a generous amount of 3M Ultra Pro Seam Sealer (see REQUIRED MATERIALS) to the seams on the inner panel. Make sure you seal all of the seams.
NOTE : You may need to fasten a length of rubber tubing to the sealer spout when applying sealer to the upper parts of the seams.
7. Inspect the area at the bottom of the A pillar and around the hood hinge. Seal any gaps that you find in the sealer.
8. Driver's side only: Inspect the grommet around the hood release cable, and seal it if needed.
9. Retest the area for leaks.
10. Reinstall all removed parts.
REQUIRED MATERIALS
3M Ultra Pro Seam Sealer (order from 3M dealer):
P/N 051135-08302 (5 oz tube)
P/N 051135-08380 (310 ml foil pack, requires P/N 08398 flexible applicator gun)
busted raditator , check heater-core . most are found inside up under your dashboard . hope that helps you !
either ac drain is clogged or heater core is leaking
you may have a septic system leak or a water main leak
Typically that leak is caused by a leak in the heating system. The heater core is under the dashboard, just above the passenger side.
I have a water leak under slab concrete and it is coming off the walk into my yard. How do I get to it to fix it without breaking the sidewalk?
heater core
Perhaps there is a leak in one of the windows or sunroof; or perhaps from the engine compartment under the dashboard.(wild guess)
under the dashboard under the dashboard
water pump or seal gone bad
Check your heater under the dash, you mAY HAVE A LEAK FROM THE HEATER CORE UNIT.
A leak. It could be a plumbing leak; are there any bathrooms or other plumbing nearby? It could also be a roof leak; don't rule that out! Another possibility is a leak from high ground water or foundation leak. Check everything you can think of.
If you discover a leaking pipe under your sink, you should turn off the water supply to the sink, place a bucket under the leak to catch the water, and then either fix the leak yourself if you are able to or call a plumber for assistance. It is important to address the leak promptly to prevent water damage and mold growth.