4 Steps To Replace Shutoff Valve

The configuration: half inch copper pipe-to-water valve-to-(3/8 inch) flexible water supply pipe-to-faucet.

4 Steps To Replace Water Valve step 1: shut main valve. Step 2: drain remaining water out. step 3: remove water supply pipe. (with 2 wrenches) step 4: remove water supply valve (with 2 wrenches)

Install the new step 1: install water valve (insert nut first and then compression ring, and then the valve). Using 2 wrenches. step 2: install the water supply flexible pipe. tight the 1/2 inch with 2 wrenches. Step 3: tight the 3/8 inch end of the flexible pipe. Step 4: turn on the main valve.

Alternative Methods

Compression-fitting valve replacement is shown in the video. Here are alternatives.

1. SharkBite Push-Fit Shutoff Valve

When to use: Quick replacement without soldering, or on copper/PEX/CPVC pipe.

Pros: No soldering or special tools, push-on connection, works on multiple pipe materials
Cons: More expensive per valve, slightly larger profile, some codes restrict concealed use
Difficulty: Easy
Estimated cost: ~$15-25 per valve

2. Quarter-Turn Ball Valve (Soldered)

When to use: Permanent, reliable installation on copper pipe.

Pros: Full-bore flow, extremely reliable, long lifespan, compact
Cons: Requires soldering (torch, flux, solder), must drain and dry the pipe first
Difficulty: Medium to Hard
Estimated cost: ~$8-15 per valve plus soldering supplies

3. PEX Crimp or Clamp Valve

When to use: Homes with PEX supply lines rather than copper.

Pros: Fast installation with a crimp ring tool, inexpensive fittings, no heat required
Cons: Requires a PEX crimp tool (around $30-50 to buy), not suitable for copper pipe without a transition fitting
Difficulty: Medium
Estimated cost: ~$5-12 per valve plus crimp rings

4. Hire a Plumber

When to use: If you are uncomfortable cutting pipe or working near the main shutoff.

Pros: Guaranteed code-compliant work, handles unexpected complications, may replace multiple valves at a discount
Cons: Service call fee, scheduling
Difficulty: N/A (hired service)
Estimated cost: ~$100-200 per valve installed

Tips for a Leak-Free Installation

Shut the main valve completely and open a faucet downstream. This drains residual pressure from the line. Even a small amount of water inside the pipe can prevent a compression fitting from seating properly, and it makes soldering impossible.
Use the two-wrench technique. Always hold the valve body with one wrench while tightening the compression nut with the other. If you turn only the nut, the valve body spins and can kink the copper pipe or crack the fitting.
Replace the supply line at the same time. Flexible braided stainless-steel supply lines are inexpensive (around $5-8 each) and have a limited lifespan. If the valve has deteriorated enough to need replacement, the supply line is likely due as well. See our guide on fixing a leaky faucet for more on supply connections.
Do not over-tighten compression fittings. A quarter turn past hand-tight is usually sufficient. Over-tightening deforms the brass compression ring and causes leaks rather than preventing them.
Apply thread sealant tape on threaded connections only. Compression fittings seal metal-to-metal and should never have tape on the compression nut. Tape belongs only on the threaded outlet where the supply line connects.
Test with paper towels. After turning the main valve back on, wrap a dry paper towel around each connection and wait five minutes. Even a tiny drip will show as a wet spot on the towel, which is easier to see than watching shiny chrome fittings.
Know which type of valve you are replacing. Older homes often have multi-turn gate valves that wear out internally and stop closing fully. Replacing them with a quarter-turn ball valve is a significant upgrade because ball valves seal more reliably and are far less likely to seize from disuse.
Keep a second bucket under the work area for 24 hours. Even a perfectly installed compression fitting can weep slightly under the first few thermal cycles as the fitting seats. A bucket catches any slow drip before it damages the cabinet floor, and you can tighten the nut an additional eighth-turn if needed.
Label the shutoff valves after installation. Attach a small tag or write on the wall behind the valve: “kitchen sink hot,” “toilet,” etc. In an emergency, you want anyone in the household to find and close the correct valve without guessing. This small step takes seconds and can prevent significant water damage down the road.

Tools You Will Need

Tool	Purpose	Approximate Cost
Two adjustable wrenches (8-inch or 10-inch)	Hold the valve body and tighten the nut	$10-15 each
Bucket and towels	Catch residual water when disconnecting	$3-8
Teflon tape (for threaded connections)	Seal the supply line connection to the valve outlet	$2-3
Pipe cutter or hacksaw	Cut copper pipe cleanly if the old ferrule is damaged	$8-15
Deburring tool or fine file	Remove burrs from a freshly cut pipe end	$5-10
Flashlight or headlamp	Illuminate the tight space under the sink or behind the toilet	$5-15

If you already own basic wrenches, the total out-of-pocket cost for a compression shutoff valve plus a new supply line is typically $15-25.

When to Call a Pro

Replacing a shutoff valve is one of the most manageable plumbing jobs, but certain situations call for professional help:

The main shutoff will not close fully. If you cannot stop the water flow at the main valve, a plumber can install a temporary freeze plug on the pipe or replace the main valve itself. Working against flowing water will not produce a reliable seal on any fitting.
The copper pipe is corroded or brittle. Older homes sometimes have thinned copper that cracks or crumbles when you apply wrench pressure. A plumber can transition to new pipe and avoid a chain reaction of leaks.
You are converting pipe materials. Switching from galvanized steel to copper or PEX requires specific transition fittings and sometimes solder work. Our article on replacing galvanized pipe to copper covers the basics, but a plumber is recommended if multiple connections are involved.
Water damage is already present. If you notice soft drywall, mold, or warped cabinetry under the sink, the issue may extend beyond the valve. A plumber can assess whether the subfloor or wall framing needs repair before closing the area back up.
Multiple valves need replacement at once. If every shutoff in the house is original and decades old, a plumber can replace them all in a single visit, often at a reduced per-valve rate. Budget around $75-150 per valve for a bulk job. For a broader look at your home’s plumbing health, check our home plumbing guide.

For the full video tutorial, visit Genius Asian.

Always verify contractor licensing and insurance in your state. Cost estimates are averages and may vary by location.