How to Fix Plumbing Supply Line Leak

A Crescent Wrench is often all that is Needed to Fix a Plumbing Supply Line Leak associated with a Kitchen or Bathroom Sink

By Mark J. Donovan

Mark Donovan of shows how to fix a plumbing supply line leak caused by a leaking faucet valve in this video.

Often a plumbing valve sitting just underneath the kitchen sink or bathroom sink is the culprit behind a small plumbing supply line leak.

The large brass nut associated with the plumbing valve is typically the source of the leak.

When twisting this particular plumbing valve open and closed, to service the faucet for example, it’s not uncommon for the large brass nut to become slightly loosened. As a result, a small plumbing line leak can occur around the nut. 

If you see mineral deposits around the nut, it’s a sure sign that this is indeed the source of your plumbing supply line leak.

In addition, particularly with the hot plumbing supply line, due to the repeated expansion and contraction of the plumbing valve as it heats up and cools down, the nut can slightly loosen up over time.

As the nut slowly loosens up, a slow leak can form around the plumbing valve and nut assembly.

To fix a plumbing supply line leak of this nature, a crescent wrench or adjustable wrench is typically all that is required.

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While holding the plumbing supply line securely with one hand use the crescent wrench to tighten the plumbing valve nut a quarter of a turn. Make sure to not over-tighten the nut or else you could damage the valve, and spring an even bigger plumbing line leak.

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