u/UnusualArrival1327

(Solved)

The plumbing pipes under my kitchen sink offer three water outlets (one for my faucet, and the other two unused.) There are two valves also. One of the valves turns on the flow for the two unused outlets. When I recently tried to install my new washing machine in my kitchen, I was unsure what to do with the third adjacent water outlet. I got a pipe cap to close it, but there remains a leak where I screwed the cap.

Edit: I went ahead and purchased a gasket, and placed it inside the cap. It fixed the leak. Thank you all!