Reputable roofing contractors tend to offer at least a one-year warranty that covers leaks due to workmanship problems. Manufacturers offer longer warranties from five to 30 years covering material defects. Within the warranty period, most leaks are fixed by the roofers without any additional charges to be paid. However, this still depends on the roofing system installed, the contract terms, and the type of leaks. Make sure you go over the fine lines of the contract before you sign.