It is a very common belief that water should be prevented from entering a house from the outside of the foundation. This belief is valid and entirely true. Unless the home (with a basement) has already been erected and buried.
Replacing the foundation drains outside or trying to seal a subterranean concrete wall will never entirely succeed. We have never heard of a contractor giving lifetime warranties for exterior work while many interior waterproofer give lifetime warranties on their work. This is due to the fact that exterior systems under so many tons of wet dirt sand and clay will all eventually clog and any exterior sheeting will eventually leak due to shear pressure, and there is no way for exterior systems to prevent water from pushing up from under the foundation.