---
title: "Shut-Off Valve Under Sink Leaking? Fixes & Costs"
url: https://dominickplumbing.com/shut-off-valve-under-sink-leaking
description: "Leaking or stuck sink shut-off valve? Compare quarter-turn and multi-turn stops, repair options and Scottsdale pricing: $95 per stop, $225 minimum labor."
lang: en
---

All articles (https://dominickplumbing.com/blog)Plumbing Repair

# Shut-Off Valve Under Sink Leaking? Fixes & Costs

October 21, 2026 7 min read

**Shut-off valve under sink leaking? Stop using the fixture, protect the cabinet and close the valve gently if it moves normally. If it won't turn, won't stop the water or leaks more when touched, shut off the home's main water supply if you can safely operate it and call a plumber. A leak at the handle may come from the stem seal; a cracked valve or one that no longer shuts off usually needs replacement.**

Written by Casey Dominick (https://dominickplumbing.com/about), founder of Dominick Plumbing, with 7+ years of plumbing experience in Arizona. Dominick Plumbing's Arizona contractor license is ROC #350819. Updated October 21, 2026.

**Our typical angle stop replacement rate is $95 per valve, with a $225 minimum labor charge.** That means a single-valve visit is not a $95 job. See the examples below, and ask for a written quote that identifies parts and any additional work before approving the repair.

## First: contain the leak without making it worse

An angle stop is the small fixture shut-off valve where the water pipe meets a flexible supply hose under the sink. Most sinks have separate hot and cold stops. Its job is to isolate the fixture, not the entire house.

1. **Clear the cabinet.** Move cleaners, stored items and anything that can absorb water. Put a container beneath the drip and dry the surrounding surfaces.
2. **Avoid electrical hazards.** If water is near a disposal outlet, wiring or an appliance connection, don't touch wet electrical equipment. Keep clear and have power isolated safely.
3. **Try only gentle hand pressure.** A traditional multi-turn stop normally closes clockwise. A quarter-turn stop closes through a 90-degree movement. Follow the valve's markings; don't force it past its stop.
4. **Escalate if it keeps leaking.** A leaking valve body remains under pressure even when the handle is closed. Use the homeowner's main shut-off if accessible and working. Don't operate utility-owned meter equipment.
5. **Check for continued moisture.** A towel is containment, not a repair. Swollen cabinet panels, wet flooring or a steady stream need prompt attention.

In a condo or rental, contact the owner or building manager when the water supply is shared. Do not shut off another unit's water without coordination. If the main valve is also seized, stop rather than forcing it.

## Where is the water actually coming from?

Dry the valve and nearby hose, then look for the first point that becomes wet. Water can travel along a hose or pipe, so a drip beneath the handle doesn't automatically prove the handle is the source.

| First wet spot | Possible problem | What to do next |
| --- | --- | --- |
| Around the stem behind the handle | Worn stem seal or packing on a serviceable multi-turn valve | Have the model checked for a manufacturer-approved repair |
| Where the flexible hose connects | Supply connector or its sealing surface | Inspect both the hose and outlet; don't assume the valve needs replacing |
| Where the valve meets the wall pipe | Inlet connection, compression seal or damaged pipe | Isolate the water upstream before disturbing the connection |
| A crack in the valve body | Failed valve body | Replace the valve; tightening a nut won't repair a crack |
| Faucet still runs with the stop closed | Internal shut-off failure, or the other supply is still open | Check hot and cold isolation separately; replace a failed stop |
| Drain trap only becomes wet when the sink drains | Drain-side leak rather than supply-valve leak | Repair the drain connection, not the angle stop |

A dripping spout is a different problem. Our dripping faucet repair guide (https://dominickplumbing.com/dripping-faucet-repair-scottsdale) covers cartridges and faucet seals. A hose bibb outside is different again; see outdoor faucet leak repair (https://dominickplumbing.com/outdoor-faucet-leak-repair-scottsdale).

## Shut off valve won't turn: don't force it

An old shut-off valve may seize from corrosion, deposits or deterioration inside the valve. A handle that spins freely without moving the stem can also indicate a broken part rather than a stiff valve.

**Do not put pliers on the handle and muscle it closed.** You can break the stem, twist the pipe or turn a slow drip into a larger leak. Don't spray household chemicals into a drinking-water valve or heat it to loosen it.

If it won't move with gentle hand pressure, the safer path is to isolate the water upstream and replace or service it. The plumber should support the pipe while working and confirm that the new stop actually stops flow, not just that its handle turns.

## Quarter-turn vs multi-turn shut off valve

These descriptions refer to how the valve operates, not how it attaches to your pipe.

| Feature | Quarter-turn stop | Multi-turn stop |
| --- | --- | --- |
| Handle movement | 90 degrees between open and closed | Several rotations |
| Internal mechanism | Depends on the model; ball-stop designs use a ball and seats | Commonly a stem and washer arrangement |
| Day-to-day advantage | Quick isolation with short handle travel | Familiar operation; some models have serviceable stem components |
| Repair considerations | Some models are replaced as a unit | Compatible repair kits may be available for specific models |
| Replacement choice | A practical upgrade when replacing a failed stop | Can remain in service if sound and functioning correctly |

For example, BrassCraft's quarter-turn ball stop (https://www.brasscraft.com/product/1-2-in-nom-comp-inlet-x-3-8-in-od-comp-outlet-1-4-turn-angle-ball-stop-less-nut-sleeve/) uses a 90-degree handle movement. Not every quarter-turn valve has identical internal construction, so choose by the actual product specification, pipe compatibility and fixture connection—not the handle alone.

A quarter-turn valve isn't immune to leaks or seizure. Good installation and a sound pipe connection matter more than treating either style as maintenance-free.

## Repair the packing or replace the angle stop?

A serviceable multi-turn valve with a small stem leak may accept a compatible stem or packing repair. Home Depot's shut-off valve repair guide (https://www.homedepot.com/c/ah/how-to-rebuild-a-shut-off-valve/9ba683603be9fa5395fab90171ed02ac) explains why worn stem components can prevent proper closure. That does not make rebuilding suitable for every valve.

Replacement is usually the better discussion when the body is cracked, the valve fails to isolate water, corrosion is substantial or a previous repair didn't last. There is no universal rule to tighten every leaking nut by a particular amount: the correct procedure depends on the valve and connection. Overtightening can damage them.

Never loosen the valve's inlet nut, remove its stem or disconnect the supply line while it is still pressurized. Turning off that same leaking angle stop is not a reliable substitute for shutting off the upstream supply before removing it.

## Angle stop replacement cost in Scottsdale: 2026 pricing

Casey's typical rate is **$95 per angle stop replaced**, subject to a **$225 minimum labor charge**. For planning, the examples use the greater of $95 times the valve count or $225—not $225 added on top of every replacement.

| Number of angle stops replaced in one visit | Planning amount using the rate and minimum |
| --- | --- |
| 1 | $225 minimum |
| 2, such as one sink's hot and cold stops | $225 minimum |
| 3 | $285 |
| 4 | $380 |
| 10 | $950 |
| 12 | $1,140 |

These are planning examples, not a promise that every installation has the same final total. Ask what the written quote includes: valve parts, supply hoses, tax, access work and any damaged pipe repair. A simple accessible stop and a corroded connection needing pipe work are different scopes.

## Should you replace all shut off valves in house?

You don't need to replace every valve just because one leaks. Start with an inspection: identify which stops leak, won't turn or fail to shut off. Replacing those failures can be enough when the remaining valves are in good condition.

Replacing a group during one scheduled water shut-off may make sense when several same-age stops are failing, a renovation already exposes them or you want dependable isolation before leaving your Arizona home for an extended period. For seasonal homes, pair that inspection with our snowbird plumbing checklist (https://dominickplumbing.com/snowbird-plumbing-checklist-scottsdale).

Count the actual valves rather than estimating by bedroom count:

- Most bathroom and kitchen sinks have two stops, one hot and one cold.
- A toilet usually has one cold-water stop.
- A dishwasher, refrigerator or filtration system may have a separate valve or a shared connection.
- A whole-house main shut-off, water-heater isolation valve and pressure reducing valve are different components and are not automatically included in an angle-stop count.

Ask for a room-by-room list and a quote before approving a whole-house replacement. Ten angle stops produce a $950 planning amount under the stated rate; twelve produce $1,140. Replacing working valves isn't a substitute for finding an underlying pressure or pipe problem.

## What a replacement visit should check

The plumber should identify the pipe material and inlet connection, isolate and relieve the water pressure, remove the failed stop without twisting the pipe, and install a compatible replacement according to its instructions. Compression, threaded, soldered and other approved connections require different methods.

After restoring water slowly, check the inlet, outlet and stem for moisture. Test the valve closed and open, confirm normal fixture flow, and inspect the supply hose for damage. If several fixtures keep developing leaks, investigate the cause; our high water pressure guide (https://dominickplumbing.com/is-my-water-pressure-too-high-scottsdale) covers pressure testing without repeating it here.

For a leaking or stuck angle stop in Scottsdale or our surrounding service areas, call Dominick Plumbing at (623) 323-4538 or visit our plumbing repair service page (https://dominickplumbing.com/services/plumbing-repair). Tell us how many valves are involved, where the leak starts and whether the main water shut-off works.

## Frequently asked questions

**Why is the shut-off valve under my sink leaking?** Possible sources include a worn stem seal, the supply-hose connection, the inlet connection or a cracked valve body. Dry the area and find the first wet spot before deciding whether to repair the valve, replace it or fix the hose.

**What should I do if my shut off valve won't turn?** Don't force the handle with pliers. If gentle hand pressure won't move it, isolate the water at a working upstream shut-off and arrange a repair or replacement. If the main valve is stuck too, contact a plumber or the building manager.

**Is a quarter-turn shut-off valve better than a multi-turn valve?** A quarter-turn valve offers quick 90-degree operation and is a practical replacement option. A sound multi-turn valve can still work well, and some models are repairable. Pipe compatibility, product construction and correct installation matter with either style.

**What is your angle stop replacement cost?** Dominick Plumbing typically charges $95 per angle stop replaced, with a $225 minimum labor charge. One or two valves therefore reach the $225 minimum; three produce a $285 planning amount. Confirm parts and additional work in the written quote.

**Should I replace all shut off valves in my house?** Not automatically. Replace leaking, seized or non-closing stops and inspect the rest. A grouped replacement may make sense if several same-age valves are failing; count actual fixture stops and get a room-by-room quote first.

**Can I replace an angle stop without shutting off the main water?** Only if another suitable upstream shut-off fully isolates that pipe and pressure is relieved. Otherwise, shut off the main water supply before removal. Closing the angle stop being removed does not isolate its inlet connection.

**Will closing the leaking valve stop the leak?** It may stop water going to the faucet, but the inlet and parts of the valve body can remain pressurized. If the valve itself keeps leaking, isolate the water upstream rather than relying on its handle alone.

## Keep reading

- Water Heaters
  ### Tankless Water Heater Descaling in Scottsdale
  How often to descale a tankless water heater in Scottsdale's hard water, warning signs, DIY steps and 2026 descaling costs ($150–$250).
  https://dominickplumbing.com/tankless-water-heater-descaling-scottsdale
- Water Heaters
  ### Hot Water Smells Like Rotten Eggs After a Softener?
  Hot water smells like rotten eggs after installing a water softener? Why it happens and how a zinc-aluminum or powered anode rod fixes it.
  https://dominickplumbing.com/hot-water-smells-like-rotten-eggs-after-water-softener
- Water Heaters
  ### Why Does It Take So Long to Get Hot Water?
  Why hot water takes so long to reach your faucet, how long is normal, and how a recirculation pump fixes it. 2026 Scottsdale costs included.
  https://dominickplumbing.com/why-does-it-take-so-long-to-get-hot-water
- Leaks & Repairs
  ### Is My Water Pressure Too High? Signs & Fixes
  Is your water pressure too high? Signs, a 2-minute gauge test, the 80 psi limit, and 2026 Scottsdale PRV costs ($450–$850).
  https://dominickplumbing.com/is-my-water-pressure-too-high-scottsdale

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