Back passenger side only floor is soak and wet ..water squirting through matt wh on 1997 BMW 528i

Water squirting through matt whole also

1 answer 3 comments
You just need to seal it? Use undercarriage coat on the locations underneath and a waterproof marine style sealer inside vehicle like "Goop".
WHERE and WHAT EXACTLY do I suppose to seal..Thanks for the first response
Have to pull up carpet and find where the water is splashing through. Should be a visible hole or rust to follow. Then seal top at this spot and underneath.
I'll try asap....thanks