As for leaks, a plumbing specialist is what you will need because leaks under your sink may be the result of holes in the sink’s basin, worn out drain mechanisms, or damaged or loose pipes or valves. The cost of the repairs will be influenced by the accessibility of the sink’s plumbing as well as with the available repair options. Across the country, the average cost of a sink repair is $158. If the leak originates from the faucet, the plumbing specialist will repair or adjust the faulty faucet fixture without touching your home’s plumbing system and the rate is usually $102 to $120.