If the wall in my basement is leaking very slightly, is the main/only solution to the actual water issue to add grading outside? What else?
It is under a deck, which I can rip up a bit and fill with dirt, but is that likely to solve it?
We noticed from slightly bubbling paint and efflorescence.
As the other commenter said, water travels far and the route is rarely linear. If you can somehow be certain it’s rain water entering the basement, then at least you know the source. But if it’s a leaky pipe then it may have eroded a path underground which is now impacting your foundation.
I’m no expert. But it seems to me that adding any sort of soil or rock would only be a band-aid fix without patching the crack where water is entering. Maybe I’m wrong about that, but it seems logical.
Iirc, all basements leak if the ground is saturated. Basement walls are made if concrete or concrete block, which is porus. With enough water on one side, it will eventually start seeping through. This is why ground slope around the house is important, and adding soil and gravel is actually a ling term fix in most cases - as long as the water runs away from the house rather than pooling around it, it won’t saturate the ground and the basement won’t seep.
Caveat - I’m no expert. But friends had this problem, and proper drainage solved it