The answer to 'best leak repair' is to first identify the source of the leak and address it properly. For minor leaks, a sealant or epoxy putty may be sufficient. For more significant leaks, you may need to replace washers, gaskets, or other plumbing components. It's important to turn off the water supply before attempting any repairs to avoid further damage.
If the leak is in a pipe or a more complex area, it's generally best to call a professional plumber. They have the tools and expertise to properly diagnose and fix the issue, ensuring the repair is done safely and effectively.