How to Install Shutoff Valves for Your Sink

W**ater** damage is the silent thief of a homeowner's peace of mind, and the most common culprit is a leaky bathroom or kitchen faucet that refuses to be silenced because you can't isolate the flow. Installing dedicated quarter-turn shutoff valves—often called angle stops—is the single most effective way to modernize your plumbing and protect your subfloors from future disasters. When done well, this project takes a messy, frantic situation and turns it into a calm, controlled maintenance task. You want a leak-free, high-quality seal that doesn't just hold today, but holds for the next decade. Forget the old multi-turn valves that get stuck or crusty over time; we are going with quarter-turn ball valves that snap shut instantly.

  1. Kill the Water Supply First. Locate your home's main water shutoff valve, typically in the basement or utility closet, and turn it clockwise to stop all flow. Open the sink faucet handles to drain the remaining water from the lines.
  2. Strip Out the Old Lines. Place a small bucket under the current plumbing connections to catch residual water. Use a basin wrench or adjustable wrench to disconnect the supply lines from the wall stub-outs.
  3. Make the Perfect Cut. Use a pipe cutter to trim the copper or PEX supply line so it is square and free of burrs or old compression rings. You need a clean, straight section of pipe for the new valve to bite into.
  4. Polish the Pipe Bright. Use a piece of fine-grit emery cloth or plumber's sandpaper to clean the outside of the pipe stub-out. Remove all paint, oxidation, and mineral deposits until the metal is shiny.
  5. Seat the Valve Body. Slide the compression nut and then the brass ferrule onto the pipe, followed by the shutoff valve body. Hand-tighten the nut, then use two wrenches to tighten it an additional half to three-quarters of a turn.
  6. Verify the Seal Holds. Close the new shutoff valves, then slowly turn the main water supply back on. Inspect each new connection for leaks before opening the sink faucet to clear the air from the lines.