Water Drips From Shut Valve

A leaky shut off valve can be a frustrating plumbing problem. Even a minor drip over time can waste hundreds of gallons of water and drive up your utility bills. Persistent drips after you've closed the valve indicate it's not functioning properly and needs repair.

What is a Shut Off Valve?

A shut off valve is an important plumbing component installed on water supply lines. It allows you to stop the flow of water to various fixtures and appliances like sinks, toilets, washing machines, outside hose bibs, and more.

These valves come in different types like gate, globe, ball, and butterfly valves. They work by physically obstructing the water's path when closed. Shut off valves have components like the valve body, stem, packing nut, seats, washers, and handle to control water flow. Typically you'll find them installed under sinks or near water meters.

Why Would Water Drip From a Closed Valve?

Ideally, no water should flow past a fully shut off valve. But valves are mechanical devices with wear and tear issues. Several problems can prevent them from fully closing and cause persistent water drips including:

• Damaged rubber washers
• Faucet seats filled with mineral deposits
• Partially closed valves
• High interior water pressure
• Corroded, bent, or cracked valve stems
• Loose packing nuts

Identifying the specific cause is essential for stopping those frustrating drips. Next, let's explore the common culprits in more detail.

Common Causes of Water Drips From a Shut Valve

1. Worn Out Rubber Valve Washers

Most shut off valves rely on rubber washers to make a watertight seal. These washers press against the valve seat when closed to stop water flowing down the supply line.

Over time hard water minerals, chlorine from treated water supplies, and normal friction during opening and closing wears down the washers. This allows water to pass the damaged seal. Replacing old valve washers is a quick plumbing fix for leakage issues.

2. Partially Closed Valves

Another common source of drips is valves that look closed but aren't completely. Some valves take multiple rotations to fully close. If prematurely stopped mid-turn, they never form an adequate seal and water leaks past.

This often happens with multi-turn gate or globe valves. Make sure to close any valves completely. Turning just enough for drips to stop isn't sufficient. Keep rotating the handle until you can't turn it any further for maximum shut off.

3. Excessive Water Pressure

Most residential plumbing systems operate at around 45-65 PSI of water pressure. But in some municipalities or buildings fed by gravity flow and tall water towers, pressures can reach over 100 PSI.

Such high pressure makes it difficult for valves to form a tight seal when closed. The immense force pushes water past the washers and valve seats. Installing a pressure reducing valve can help restrict flow to more normal levels.

4. Mineral Deposits

Hard water full of dissolved minerals like calcium and magnesium carbonate takes a toll on plumbing. Valves and seats become encrusted with lime and calcium deposits over time.

This buildup prevents valves from fully closing and seals from forming correctly. Water then leaks through tiny gaps around the valve parts. Descaling valves and seats helps remediate this common issue.

5. Damaged Valve Stems

The valve stem is what you turn to open or close water flow. These stems connect to washers and seats to control positioning. Like other components, stems suffer wear over decades of use and mineral deposits.

Excess friction can bend stems so they don't correctly pressurize washers for an airtight seal. Corrosion also damages valve stems and prevents smooth operation. Replacing bent, cracked, or broken stems is necessary to fix chronic leaks.

Troubleshooting Water Drips From a Shut Valve

Now that you know what typically causes water to drip from closed off valves, it's easier to troubleshoot your leaky plumbing. Follow these tips to inspect your system and determine why your valve isn't fully stopping flow:

Check Valve Washers and Seats

Worn out rubber washers are a convenient fix if they happen to be the source of your leaks. Start by fully shutting off the valve. Then disassemble it to expose the washers and inner components.

Inspect washers for cracking, misshaping, tearing, or extreme hardness from mineralization. Use your fingers to feel for pliability. If you can pinch or bend washers without damage, they may still function correctly.

Also inspect valve seats for debris, heavy mineral buildup, and irregular wear. A smooth, clean seat is vital for washers making flush contact to control water properly. Replace any damaged washers or clean/resurface seats as needed.

Confirm Full Valve Closure

Another quick check is verifying your valve fully closes. This is common with gate and globe designs requiring multiple handle turns. Slowly close your shut off valve while observing water movement past the handle shaft.

Keep turning until flow stops completely - this confirms closure. If drips continue, issue may lie with worn components. Multi-turn valves staying perpetually partly open is why many plumbers replace them with modern quarter-turn ball valves.

Check House Water Pressure

Determining your home's water pressure takes just minutes with an inexpensive gauge that connects to any exterior hose bib. High pressure over 80 PSI strains valve parts and complicates complete shut off.

Consult local building codes for pressure requirements. Many areas mandate regulator valves if levels exceed 80 PSI. Get pressure back to 50-65 PSI range for easier valve closure without leaks.

Inspect for Mineral Buildup

Check valve components like rubber seats and stems for heavy lime and calcium deposits which prevent smooth operation. Soaking affected parts in descaling acids like white vinegar or CLR breaks down this mineralization so valves function normally.

Prevention is key here too - installing water softeners and filters upstream stops scale forming in the first place. Maintain your water system to avoid future shut off valve grief.

Fixing a Leaky Shut Off Valve

Once you've diagnosed why water keeps dripping from a closed valve, it's time for repairs. Here are common solutions for resolving shut off leakage issues:

Replacing Valve Washers

If worn washers are confirmed as the culprit, replacement restores full water shut off. Bring the valve make and model to your local plumbing supply store to get the correct rubber washers and seals.

Use pipe wrenches to disassemble the valve and gain access to internal components. Clean mineral deposits and other debris from old washers before inserting fresh ones. Reassemble and confirm full water stoppage when closed.

Installing New Shutoff Valves

For gate, globe, saddle, or multi-turn ball valves more than 10 years old, replacement may be your best option. Modern quarter-turn ball valves are inexpensive, easy to install, and very reliable.

Measure the faulty valve connections and get an identical replacement. Close main water lines and cut out the old valve. Use joint compound and pipe wrenches to secure new valves meeting building code requirements.

Sometimes sticky or hard-to-turn valves prevent adequate closure and water stoppage. Special valve lubricating oil or sealant grease can make operation smooth again.

Apply lubricant to valve stems and sealant grease to washers and seats as directed on products. Allow time to penetrate before turning valves from fully closed to fully open repeatedly. This spreads the lubrication internally.