I have a 1998 Chevy Suburban.whenever it rains the driver side floorboard becomes wet. door seals are good. where could the leak be coming from?

Check the door drain vents in the bottom of the door ensure they are not blocked, when it rains the rain travels through the door at the window seal and escapes through opening,
. Open the door and check underneath. If blocked water fills the door and gets into the car. Also if the car has a sunroof water may be coming through there. If not this try going through a car wash while in the car and seen if you can see it hear any water getting in my

Has it been raining? If so, you either have a hole in the floorboard or possibly a leaking door seal. If it hasn't been raining then either your heater core is leaking (the wet will smell sweet, like antifreeze) or your AC condensor pan is leaking (the wet will be a clear liquid)

it is getting in from somewhere run water over the car using a garden hose and you will find it.look for where its wet at the highest point and thats probably the spot.

Inspect the condition of the rubber door seals for tears . Age will make them stiff so they no longer seal around the door.

most likely cause is water intrusion through the cabin filter

pull the filter
if wet then you need to find something that diverts water away
many OEM's have had this problem but nothing on file for this vehicle

There is a great possibilty that there is a leak on the Left Side of the Windshield. It is most likely in the area of the upper left side.
The reason for this conclusion is:
The rain water is coming in the Left Upper Side; and either coming down the "A" Pillar, or traveling underneath the trim on the inside roof and coming down the "B" Pillar.
The only other explanantion is a torn, worn, cracked or dislocated Weather Seal on one or both of the doors, allowing rain water to come in. Inspect very carefully these Weather Seals, especially on the top front portion of the rear door.
To help you locate these after a hard rain:
Take the trim panels off the "A: and "B" Pillars and the Roof Line above both Doors. Check for wetness underneath the trim. Or take these trim panels off, and place folded paper towels under the trim panels; reattach the trim panels and wait until it rains. Afterwhich, take these trim panel off and check the paper towels for wetness.
The Windshield Seal is easily inspected for cracks and tears.
Let me know if this helped, or if you have additional information or questions. Feel free to contact me at FixYa.com!

Look for moisture on the glass of the windshield, as well as the passenger side door, if thebottom seal isnt making contact on the door glass water will run in threw the door

There are three possibilities, the winshield seal is leaking, the door seal is defective or the door window seal is leaking, sometimes you can find out by having an assistant inside the car observe the areas mentioned while you spray the car with the pressure washer at the car wash.

do you have a sun roof, if so start there, because there are two hoses at the back corners of the roof pan that allow water to drain, if they leak, they will soak the rear floorboards, and if not that check the door jam seals.(note that if the plugs on the floor are missing that will be verry hard not to have wet carpet)........let me know?

check out your door seals may need replacing. drive it thru a carwash to locate the spot.