A water shut-off valve is a home-saver in an emergency – allowing you to quickly shut off your water supply and avoid damage to your home.

In this guide, we'll run through the prices for replacing a manual stop tap and how they compare to the cost of installing an automatic water shut-off valve.

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How much does it cost to replace a stopcock or water shut-off valve?

Replacing a manual internal stopcock (also called a stop tap or stop valve) typically costs £150 on average, including labour. Meanwhile, replacing a manual external stopcock works out slightly more, at around £225, including labour.

However, if you want an automatic water shut-off valve that detects leaks and cuts the water supply without you needing to act, prices climb.

Keep reading for a full breakdown of stopcock costs, so you know what to expect before you call a plumber.

But first, let's clear up any confusion over what a stopcock is - and how it differs from an automatic water shut-off valve.

What is a stopcock?

A manual stopcock (sometimes called a stop tap or stop valve) controls the flow of water into your home. You'll usually find it:

• Under the kitchen sink

• In an airing cupboard

• Under the stairs

• Outside on pavement or near a water meter (often the responsibility of a water company)

It works as simply as turning it clockwise to shut off your water supply, and anti-clockwise to turn it back on.

How much does a stopcock replacement cost?

Most main water valves should last around 10 to 20 years before rusting or failing.

But if the time has come to replace your existing internal stop tap, you can expect to pay between £100 and £200 for a plumber to replace it.

Meantime, budget between £150 and £300 for a plumber to install an external stop tap in your garden or property boundary.

That said, exactly how much you pay will depend on where the valve is located, and how tricky access is.

That's why we always recommend contacting a tradesperson directly to get an exact quote.

Why not download our free mobile app to connect with local plumbers we've checked and reviewed in your area?

Not quite ready to contact a tradesperson? Try our handy cost calculator below for an instant estimate.

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What is an automatic shut-off valve?

An automatic shut-off valve goes one step further than a manual stopcock by detecting leaks or unusual water usage in your water pipes and automatically shutting off the water.

This stops the leak in its tracks, preventing further damage to your property and possessions.

But, as you'd expect, this extra protection comes at a higher cost. Let's get into it.

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How much does an automatic water shut-off valve cost?

It usually costs between £200 and £420 to get a smart valve installed, depending on the features you need.

There are two main types of leak detection and automatic shut-off systems:

1. Moisture sensor automatic water shut-off systems

• How it works: Uses moisture pucks to detect moisture in the home where it shouldn’t be. The system will either alert you or automatically shut off your water supply

• Best for: Best for homes where you want targeted protection around high-risk appliances or rooms, as moisture pucks can be placed in each room

• Costs: Around £310

2. Flow-based leak detection systems with automatic water shut-off valves

• How it works: A continuous flow of water, rather than moisture, detects when something is wrong. For example, if the system notices that water has been running for 20 minutes non-stop, it will automatically shut off your water

• Best for: Busy households or second homes where leaks can be detected even when nobody is at the property

• Costs: Around £310

What affects the cost of replacing a stopcock?

The cost to install a shut-off valve will vary based on factors such as:

• Type of valve (standard or automatic?)

• Whether it’s installed by a professional (or whether you find a system suitable for DIY installation)

• Accessibility (if the stopcock is buried in the wall or under floorboards, labour time (and cost) goes up)

• Location (plumber rates vary across the UK)

Additional costs to consider

• Call-out fees (if it's an emergency)

• Pipework condition (an old or corroded pipe section near the valve may need replacing at the same time)

• Water damage repair work (if a leak has occurred)

Ultimately, the best way to get an exact steer on the costs of a stopcock replacement is to contact a plumber local to you.

On Checkatrade, you'll only find trades who meet our high standards and pass up to 12 checks.

How long does it take to replace a stopcock?

A standard internal stopcock replacement takes a plumber 30 minutes to 1 hour.

However, if the pipework nearby is corroded or difficult to access, allow up to two hours.

Meanwhile, an automatic leak-detection system takes a little longer to install and configure – typically one to two hours for a qualified plumber.

Every Checkatrade job is backed by our £1,000 guarantee

Up to £1000. Eligibility criteria and T&C’s apply.

Is replacing a water valve worth it?

A new stop tap might not be the most exciting home improvement job you'll make, but it's an important one.

Benefits of replacing your water shut-off valve include:

• Stops leaks quickly: Essential if a pipe bursts or an appliance starts leaking

• Helps prevent expensive damage: To floors, walls, furniture and belongings

• Makes maintenance easier: Quicker to isolate the water supply when carrying out repairs or installing new fixtures, like showers and taps

• Automatic systems offer extra protection: Smart shut-off valves can detect leaks and turn off the water automatically

• You may save on insurance: Some home insurers offer discounts for approved leak-detection and automatic shut-off systems

DIY vs hiring a plumber

Replacing a standard internal stopcock:

Fitting a manual stop tap is doable for a confident DIYer. You'll need to turn off the water at the street or outside stop tap, swap the old valve, and restore the supply.

But unless you're comfortable with basic plumbing, a checked plumber is the safer call.

Replacing an automatic water shut-off valve:

Fitting a smart water valve is slightly trickier. That's why we'd recommend it being fitted by a professional plumber. Incorrect installation can cause false shut-offs or, worse, fail to detect a real leak.

Why use Checkatrade?

• Checked - Every Checkatrade member must pass up to 12 checks and commit to upholding the Checkatrade Standard

• Guaranteed - Jobs booked through Checkatrade are covered up to £1,000 (T&Cs apply)

• Reviewed - Over 6.2 million verified reviews from real jobs have been published on Checkatrade on everything from communication, tidiness, timekeeping, and quality of work

Install a water shut-off valve: Cost checklist

• Try to get at least three quotes from tradespeople before agreeing to a job (so you know you're getting a fair price)

• Always hire a plumber who's been well reviewed

• Check what’s included in your quote (supply of new stop tap, removal of old stopcock, and installation?)

• Group smaller plumbing jobs together for one visit (instead of paying out for multiple call-out fees)

From installing a new tap and unblocking drains, to boiler maintenance and bathroom installations, take a look at our plumbing hub for help with all your plumbing needs.

FAQs

How much does it cost to replace a stopcock?

Replacing an internal stopcock (stop tap) typically costs between £100 and £200 , including parts and a plumber's labour. The exact price depends on where the valve is located and whether any nearby pipework needs replacing at the same time.

Do I need a plumber to replace a stopcock?

Most people hire a plumber, as it's the safer bet. A poorly fitted stopcock can leak or fail when you need it most. A qualified plumber will also check the surrounding pipework while they're there.

How do I find my stopcock?

Your internal stopcock is usually under the kitchen sink, in an airing cupboard, or under the stairs. If you can't find it indoors, there's also an external stop tap in the pavement outside your property.

Our how to turn off the water in your house guide has more handy tips. But if all else fails, your water company can help you locate it.

How long does a stopcock last?

A well-maintained stopcock should last 20–30 years, but older brass valves can seize up or start to drip. If yours is stiff or leaking, have a plumber inspect it – replacement is usually straightforward if caught early.

What is the difference between a stopcock and a stop tap?

A stopcock and a stop tap are the same thing. Both terms refer to the valve that shuts off your home's water supply. 'Stopcock' is more common in the trade. 'Stop tap' is what most water companies and homeowners say.

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