The Complete Guide to Valves

Ball valve: a hollow metal ball inside the valve body rotates 90 degrees. Handle parallel to pipe = open (ball hole aligns with flow). Handle perpendicular = closed (solid side of ball blocks flow). One quarter turn from full-open to full-closed. Gate valve: a metal gate (wedge or disc) raises and lowers on a threaded stem. Turn the handle counterclockwise to raise the gate (open). Clockwise to lower it (closed). Takes 5-10 full turns from open to closed. The gate sits in the flow path when partially open, causing turbulence and wear.

Ball valves almost never seize. The ball rotates on Teflon seats with minimal friction. Even after 10 years of non-use, a ball valve turns smoothly. Gate valves seize frequently. The threaded stem corrodes, mineral deposits lock the gate, and the packing around the stem dries out. A gate valve that has not been operated in 3-5 years often will not turn -- or turns halfway and sticks. This is why the main shut-off fails during emergencies: the old gate valve has been sitting untouched for years.

Ball valves (full-port design) have the same internal diameter as the pipe. Zero flow restriction when fully open. Standard-port ball valves have a slightly smaller opening -- adequate for branch lines but not ideal for main lines. Gate valves are also full-bore when fully open -- the gate retracts completely out of the flow path. Neither valve type restricts flow when fully open. The difference is in partial opening: ball valves should be fully open or fully closed (not throttled). Gate valves can throttle flow but the gate erodes when partially open.

Ball valves: $5-$20 for residential sizes (1/2 to 1 inch). Available everywhere. Brass is the standard material for water supply. Ball valves cost slightly more than gate valves at the same size -- $2-$5 more. Gate valves: $3-$15 for residential sizes. Also widely available, but increasingly found only in replacement stock (not new construction). The price difference is negligible -- $2-$5 more for a valve that is dramatically more reliable.

Use a ball valve for: every residential application. Main shut-off, toilet supply, sink supply, washing machine, water heater, outdoor hose bibs. There is no residential plumbing application where a gate valve is better than a ball valve. Use a gate valve only when: replacing an existing gate valve in a system where the connection type requires it and conversion to ball valve is not practical. Or in industrial applications where throttling flow is needed (not residential).

How to install a PRV to protect your plumbing from high water pressure.

How to replace an old main shutoff with a modern full-port ball valve.

How to swap old gate valves for reliable quarter-turn ball valves at sinks, toilets, and appliances.

How to install a thermostatic mixing valve for safe, consistent water temperature.

Why and how to periodically operate your shut-off valves so they work when you actually need them.

How to test and adjust your pressure reducing valve to protect your plumbing from high water pressure.

How to test the temperature and pressure relief valve on your water heater -- your most important safety device.

How to fix common valve leaks at the packing nut, handle, and body connections.

What happens financially when valves fail -- from seized shut-offs to PRV failures and burst hoses.

What it costs to replace a shut-off valve -- fixture valves, main shut-off, outdoor hose bibs, and why upgrading to ball valves is worth every dollar.

What plumbers charge to install or replace different types of plumbing valves.

What different plumbing valves cost -- ball valves, gate valves, check valves, PRVs, and mixing valves.

What it costs to upgrade all shut-off valves, add a PRV, and modernize your home's valve infrastructure.