Tarps are pretty capable of blocking out water, yet they are not meant to be a long-term solution for leaks. If a leak is left unresolved, it could lead to further damage and problems for a house. California has had its fair share of rainfall this season, and locals should not underestimate rainy weather, even if it brings nothing stronger than a drizzle.
Although leaks might seem small and harmless when they first manifest, they can get a lot worse if ignored. The water damage they cause can make wooden fixtures rot and ultimately ruin the insulation that lies between the roof and the ceiling. Leaks can also trigger mold growth that can further damage the house, as well as pose health hazards to occupants. In the absolute worst-case scenario, severe water damage can weaken a structure enough to cause the entire roof to cave in.