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Shut Off Water and Depressurize — Shut Off Main Water Supply and Drain Lines

Beginner

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How to Replace a Leaky Angle Stop (Shutoff Valve) Under Your Sink · Step 1 of 8

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The first and most critical step is to shut off the water supply. Locate the main water shutoff for the house or the specific shutoffs for the bathroom and turn off both the hot and cold water lines leading to the shower valve. After the water is off, turn the shower handle to the fully open position to drain any remaining water and release all pressure from the system.

Goal: Isolate Water Supply

  • Failure to open the valve after shutting off the water can lead to damage during disassembly, as pressure can still be trapped inside.
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FAQs

What's the most critical safety step before beginning the angle stop replacement?

The most critical step is always to shut off the main water supply to your house completely, not just the valve under the sink. This prevents potential flooding and ensures no water pressure is present while you're working on the pipe.

How long should a beginner expect this project to take, and what is the approximate cost?

For a beginner, this project typically takes 1 to 2 hours, allowing time for preparation and careful leak checks. The material cost is relatively low, mainly for the new angle stop and a new supply line, usually ranging from $20 to $40.

What tools do I need beyond basic wrenches for this project?

While adjustable wrenches and pliers are essential, 150-grit sandpaper is crucial for cleaning the copper pipe to ensure a good seal. You'll also need a bucket for draining water and plenty of absorbent towels (like WYPALL L40 or Scott Rags) to manage spills.

What's a common mistake beginners make that can lead to leaks after installation?

A common mistake is not thoroughly cleaning and preparing the copper pipe surface before installing the new compression fitting. Ensure the pipe is smooth, free of burrs, and clear of old compression ring residue using 150-grit sandpaper for a watertight seal.

Shut Off Water and Depressurize — How to Replace a Leaky Angle Stop (Shutoff Valve) Under Your Sink (Step 1, Video 1) | Stesso