Why Does My Outside Tap Won’t Turn Off Completely — and How Do I Stop the Drip?

If your outside tap won’t turn off completely, the good news is that it’s one of the most common — and cheapest — plumbing fixes you’ll ever do. In 9 out of 10 cases, the culprit is a perished rubber washer sitting on a corroded brass seat inside the tap. Outdoor taps (also called garden taps, hose bibs, sillcocks, or bibcocks) live a hard life: freezing winters, mineral-heavy water, grit from the garden hose, and years of being cranked shut with a bit too much muscle. All of that wears out the sealing washer until it can no longer press tightly enough to stop the flow. This guide walks you through exactly why it happens and how to fix it yourself, without a plumber.

Why won’t my outside tap turn off all the way — what’s actually broken?

Your outside tap won’t shut off because the seal that’s supposed to block the water has failed — usually the washer, sometimes the valve seat, occasionally the whole cartridge or spindle. Water is under constant pressure in your supply pipe, so even a tiny gap lets it push through as a steady drip or a thin stream.

Here’s what’s happening inside a traditional compression outdoor tap. When you turn the handle, a threaded spindle drives a small rubber or fibre washer down onto a machined brass ring called the seat. When the washer presses flat against the seat, the water stops. Over time three things go wrong:

• The washer hardens, cracks, or gets grooved. Rubber perishes with age, heat, and chlorine in the water. A washer that used to be soft and springy turns brittle, so it can’t form a tight seal even when fully closed.
• The brass seat corrodes or gets scored. Grit and mineral scale scratch the smooth ring the washer sits on. Now even a brand-new washer can’t seal against the rough, pitted surface.
• The spindle threads or O-ring wear out. If the tap feels loose, spins freely, or leaks from around the handle rather than the spout, the spindle O-ring or the headgear itself is worn.

Modern outdoor taps sometimes use a ceramic disc cartridge instead of a washer. Those fail differently — the discs chip or clog with debris — but the fix is similar: you swap the cartridge rather than the washer. If you’re not sure which type you have, don’t worry; the first steps below tell you how to find out. It’s worth understanding the part at the heart of the tap, and our guide on what a cartridge for a faucet is and when it needs replacing explains the difference between washer-type and cartridge-type valves in plain terms.

How do I fix an outside tap that keeps dripping — step by step?

To fix a dripping outside tap, shut off the water, open the tap to drain the line, unscrew the headgear, replace the worn washer or cartridge, and reassemble. Most people finish in 20–30 minutes with a single adjustable wrench and a $2–5 washer kit. Here’s the full sequence.

1. Turn off the water supply. Find the isolation valve on the pipe feeding the outside tap — often a small lever or screwdriver-slot valve just inside the wall, in a garage, or under a kitchen sink. If there isn’t one, close your main indoor stopcock. Turning off only the outdoor supply lets the rest of the house keep running.
2. Open the tap fully and let it drain. This releases the pressure and empties the last of the water in the pipe, so you won’t get soaked when you open it up.
3. Unscrew the bonnet / headgear nut. Grip the flat hexagonal nut just below the handle with an adjustable wrench and turn counter-clockwise. Hold the tap body steady with your other hand or a second wrench so you don’t twist the pipe in the wall.
4. Pull out the spindle and inspect the washer. At the very bottom of the spindle you’ll see a washer held by a small brass nut or screw. If it’s flattened, cracked, grooved, or gummy, that’s your leak.
5. Replace the washer. Undo the retaining screw, fit an identical new washer (the most common outdoor sizes are 1/2″ and 3/4″), and tighten the screw snug but not crushing.
6. Check the seat. Shine a light down into the tap body. If the brass ring looks pitted, green, or scratched, re-face it with a seat-grinding tool, or fit a nylon seating washer that molds itself to minor imperfections.
7. Wrap the spindle threads with PTFE tape, reassemble in reverse, and hand-tighten the bonnet, then a quarter-turn more with the wrench.
8. Turn the water back on slowly and test. Open and close the tap a couple of times. No drip? You’re done.

If, after all this, the tap still weeps and the seat looks badly corroded, it’s usually faster and more reliable to swap the entire tap or the headgear assembly than to keep grinding. Replacing the whole unit follows the same logic as swapping any threaded fixture — the approach in our walkthrough on how to replace a bath tap unit without flooding the bathroom transfers almost directly to an outdoor tap, since both are about isolating the water, breaking the old threaded joint, and sealing the new one properly.

What tools and parts do I need before I start?

You need very little: an adjustable wrench, a washer or cartridge kit that matches your tap, PTFE (plumber’s) tape, and maybe a seat-grinding tool. Total spend is usually under $15. Here’s a quick shopping list so you only make one trip to the hardware store.

• Adjustable wrench (or two) — to loosen the bonnet nut and hold the body still.
• Assorted tap washers — a mixed pack of 1/2″ and 3/4″ rubber and fibre washers costs a couple of dollars.
• Replacement ceramic cartridge — only if your tap is a lever-style ceramic-disc type.
• PTFE tape — to reseal the spindle threads and prevent handle-leaks.
• Silicone grease — a smear on the O-ring keeps the handle turning smoothly.
• Seat-grinding tool or nylon seating washer — for a scored valve seat.
• Old towel and a bowl — to catch drips.

Should I repair the washer, replace the cartridge, or fit a whole new tap?

Repair the washer if the tap body is sound and only the spout drips; replace the cartridge if it’s a ceramic-disc lever tap; and fit a whole new tap if the body is corroded, the threads are stripped, or it leaks from the base. The table below lays out which route fits your situation, the rough cost, and the skill level.

A simple rule of thumb: if the tap is less than 10 years old and the body is solid brass in good shape, repair it. If it’s an old chrome-over-pot-metal builder’s-grade tap that’s been through a decade of frost, spend the extra $30 and fit a quality frost-resistant replacement — you’ll likely be back out there next spring otherwise.

Why does my outside tap leak more in winter, and can frost cause this?

Yes — frost is a major reason an outdoor tap suddenly won’t turn off. When water trapped inside the tap freezes, it expands and can crack the internal seat, split the washer, or even fracture the body. So a tap that sealed fine in autumn can start dripping the moment it thaws in spring.

If you live somewhere with hard freezes, this is worth designing out permanently. A frost-free (frost-proof) sillcock places the actual shut-off valve 6–12 inches back inside the heated wall, so the water stops well behind the freeze line and the exposed pipe drains empty. If you keep replacing washers every spring, upgrading to a frost-free model is the real fix. Either way, always disconnect the garden hose before winter — a connected hose traps water in the tap and is the single most common cause of frost splits.

Is it safe to keep using a tap that won’t fully turn off?

You can use it short-term, but don’t ignore it — a constant drip wastes water, drives up your bill, and in freezing weather can lead to a burst pipe or water damage to the wall. A tap dripping once per second wastes roughly 3,000 gallons a year, so even a “small” leak adds up fast.

There’s also a hidden risk: water tracking down the pipe and into the wall cavity where it can rot framing or feed mold. If you notice damp patches on the interior wall behind the tap, or water pooling at the base, treat it as urgent. The same principle applies to any fixture leaking where you can’t easily see it — our breakdown of why a faucet leaks under the sink and how to trace it shows how to distinguish a supply-line leak from a valve leak, which is exactly the diagnostic skill you want here.

When should I just call a plumber?

Call a plumber if you can’t find or turn off the water supply, if the pipe feeding the tap is buried in the wall and turning the bonnet spins the whole pipe, or if you spot signs of a burst or hidden leak inside the wall. Those situations risk turning a $2 fix into a flooded wall cavity, and a pro has the tools to isolate and repair the buried section safely.

For everyone else — a standard wall-mounted or pipe-mounted garden tap with an accessible shut-off — this is a genuinely beginner-friendly job. If your tap is wall-mounted and you decide to replace it outright, the mounting and sealing steps mirror our guide on how to install a wall-mounted tap yourself without hiring a plumber, which covers getting the threads sealed and the escutcheon flush against the wall.

FAQ

Why does my outside tap drip even when it’s fully closed?

Because the rubber washer inside has hardened or cracked and can no longer press tightly against the brass valve seat. Water under pressure squeezes through the tiny gap. Replacing the washer is a $2 fix that solves this in the vast majority of cases. If a new washer doesn’t stop it, the valve seat itself is likely scored and needs regrinding or a nylon seating washer.

Can I replace an outside tap washer without turning off the mains?

No — you must isolate the water first, either at the outdoor supply’s isolation valve or the main indoor stopcock. Opening the headgear while the line is pressurized will send water spraying everywhere and could flood the area. Once the supply is off, open the tap to drain the residual water before you unscrew anything.

How much does it cost to fix an outside tap that won’t turn off?

If you DIY, expect to spend $2–15 on a washer or cartridge kit and PTFE tape. Replacing the entire tap runs $20–60 for the part. A plumber’s call-out typically starts around $80–150, so a washer swap is one of the best money-savers in home maintenance — especially since it takes most people under half an hour.

My outside tap handle spins freely and won’t shut off at all — what’s wrong?

The spindle threads or the internal headgear have stripped, so turning the handle no longer drives the washer down onto the seat. In this case a new washer won’t help. You’ll need to replace the headgear assembly or, more commonly, the whole tap, since the internal thread that does the actual sealing has failed.

How do I stop my outside tap from leaking every winter?

Disconnect the garden hose before the first freeze, drain the tap, and — for a permanent fix — upgrade to a frost-free sillcock that keeps the shut-off valve inside the heated wall. Repeated spring leaks are almost always frost damage from water trapped in the tap or an attached hose over winter.

Is a dripping outside tap an emergency?

A slow drip isn’t an emergency, but don’t let it linger. Beyond wasting thousands of gallons a year, a leak in freezing weather can burst the pipe, and water tracking into the wall can rot framing or grow mold. If you see damp inside the wall or water pooling at the base, treat it as urgent and shut off the supply.

About the author: This guide was written by the KES Faucet technical content team, drawing on hands-on experience installing and servicing residential faucets, valves, and outdoor taps. We test fixtures against real-world conditions — hard water, freeze-thaw cycles, and everyday wear — before we write about them.

About KES / kesfaucet: KES has manufactured faucets and bathroom fixtures for over 20 years, shipping to homeowners and trade installers worldwide. Our valves and cartridges are built to recognized flow and durability standards (including ceramic-disc cartridges rated for 500,000+ open/close cycles), and our fixtures are backed by a manufacturer’s warranty. When we recommend a repair or a replacement part, it’s grounded in the same standards we hold our own products to.