The basement walls inevitably develop cracks which can be both narrow as well as wide up-to 1.5". The cracks can be due to many reasons but main reasons include thermal movement and drying shrinkage. The narrow cracks seem innocent but over the time they cause lot of problems. All cracks start leaking at some or other time.
Now cracks can not give structural failures as there are easy ways to fill up the cracks. Pour-in concrete walls can be injected with low pressure epoxy or polyurethane foam. This permanent, cost-effective and reliable method is preferred by everyone. But a concrete block walls can't have epoxy injection. The cracks are fully filled and the treatment arrests the seepage of water. Drilling is not needed to inject the treatment. The injection is made from the inside the no digging is required. Basement is the diciest place from where the seepage occurs and the complete building decays. Thus basement walls have to be repaired at the earliest.