Repairing a kitchen sink leak is often a task that you can fix your self. The first thing you need to do is clear out the stuff stored under the sink and you will need a flashlight and a paper towel or, rag. I also like to wipe up any water in the bottom of the cabinet because nobody likes lying in a puddle looking for a leak and in some cases seeing a new puddle starting to appear can offer clues where the leak is. You will then need to get under the sink and find where the water is leaking. I always start with the sink faucet turned off and look for leaks in the water supply lines first. There should be a hot and a cold pipe coming either out of the wall or floor supplying water to the kitchen sink faucet, these supplies may also supply water to other appliances such as an icemaker or, dishwasher. I examine all the supply lines all the way up to the faucet looking for wetness and when I find wetness wipe it dry looking for the wetness to return. One of the things I do when checking for slow seeping leaks is use a sheet of toilet paper to touch the edge against a suspected leak. Even a very small amount of water seeping will leave a considerable water stain on the toilet paper which can be more thoroughly dried with the toilet paper and rechecked with a dry edge again and again. When doing this also look under the faucet for rust and the wood counters for signs of water stains and damage, which can signify water leaking from above. I examine all connections, valves, and the pipes themselves. I pay special consideration to valves under the handle where the stem comes out of the valve, which would signify a leaking packing on the valve. Frequently when icemakers are installed the installer uses the saddle valve that comes in the icemaker installation kit, which are bad news. Saddle valves are frequently the cause of leaks and you should consider replacing them with a valve like the ones normally for faucet and toilet supply valves.
Once the supplies have been thoroughly checked I turn on the cold water on the faucet and continue examining under the sink for leakage. With the water running watch for water leaking from the area under the faucet, check the side sprayer hose for water coming down the hose both from the either the connection at the bottom of the faucet or, the sprayer end. Turn on the hot water also and recheck and run both hot and cold together hard as well sometimes-large volume can be the key to making the leak. You also want to check the drain for leaks at the basket strainer, tailpiece, disposer, slip joint connections and so on looking for any drips or even wetness. Fill the sink with a large volume of water and reexamine the basket strainer with water standing in the sink giving it time to leak. Release the water from the sink allowing the water to drain reexamining all the drain components for leakage while the large volume of water is draining. You may also want to fill and drain the dishwasher to check the dishwasher drain for leakage.
After completing the checks below move topside and pull out the sprayer hose move the hose connection around to the sprayer continuing to check for a leaking connection. Use a wet sponge to wring out water around the faucet to check for leakage where the faucet attaches to the sink and recheck underneath where the faucet attaches to the sink. Finally wet the countertop surrounding the sink and against the backsplash again checking for leaks. Once you have identified where the water is coming from and exactly what is causing the leak you have completed the all important first step in repairing a kitchen sink. The actual repair of whatever leaking is going to have to be the subject of another article, which can specifically address your issue and the repair. Finding the leak is the first big step to repairing your kitchen sink leak.