Tricks to Install Plumbing Underneath a Kitchen Sink Without Leaks

Leak Detection

• To prevent or fix leaks, you have to inspect the pipes under the sink. Wipe up any existing puddles of water under the plumbing and fill the sink with tepid water. Using cold water will form condensation on the pipes, which may look like leaks. Wipe the pipes dry and inspect the connections with a flashlight. If they don't show water droplet formation, open the sink drain to see if the water pressure in the pipes results in leaking and note the problem areas.

Pipe Alignment

• If you observe leaks, the cause may be misaligned pipes that sometimes get jostled by items stored in the cabinet or are shaken out of line by the vibration of the garbage disposal. Loosen but don’t remove the metal slip nuts, straighten the pipes and tighten the nuts. Use extra care when tightening plastic nuts as they will crack or break if over tightened. It helps to steady the pipe with pliers while you loosen and tighten the nuts. You may have to realign several connecting pipes to straighten other ones. If the leaks persist, the pipes may have deteriorated or the connecting threads have become stripped, both of which require pipe replacement.

Strainer Leaks

• If the pipes are free of leaks, the leaks may be coming from the basket strainer, which is located right under the drain on the underside of the cabinet top. Plumber’s putty, the main sealant for the strainer, shrinks, cracks and hardens over time. Minor leaks can often be fixed by tightening the nut holding the strainer in place. Persistent leaks may require putty replacement. You can just replace the putty around the old strainer if it’s in good shape, however, replacing the strainer with a new one will make the system more reliable and less apt to spring future leaks.

System Replacement

• In cases where the leaks are persistent or come from multiple locations, replacing all the plumbing under the kitchen sink may be the best option. Pipes deteriorate over time from minerals in the water, age and general wear, fasteners corrode and loosen, and sealants lose their waterproof components, so replacing everything at once is often more cost-effective and time-saving.