What Should You Check Before Calling a Plumber About a Leak?

Discovering a water leak at home can be stressful, especially when you’re unsure where it’s coming from or how serious the problem might be. Whether you’ve noticed a dripping pipe, water beneath the kitchen sink or an unexplained damp patch, knowing what to check before calling a plumber about a leak can help you take the right steps.

Some leaks are easy to identify, while others can remain hidden behind walls, beneath floors or around plumbing connections. Although you shouldn’t attempt repairs you’re not confident carrying out, there are several simple checks you can make safely.

In this guide, we’ll explain what to look for, how to limit potential water damage and when it’s time to contact a professional plumber.

What Should You Do First If You Find a Water Leak?

If you discover a water leak, the first priority is to prevent further damage where it’s safe to do so. Check whether you can identify the source and turn off the affected water supply using an isolation valve or your home’s main stopcock.

Before calling a plumber:

If water is escaping quickly, spreading through your property or affecting electrical fittings, prioritise safety rather than investigating the problem yourself.

5 Things to Check Before Calling a Plumber

1. Identify Where and When the Leak Occurs

Start by looking at common problem areas, including beneath sinks, around toilets, behind appliances and near exposed pipework.

Check whether the leak happens continuously or only when you use a particular fixture. For example, water appearing beneath a sink when the tap is running could indicate a problem with the waste pipe, tap connections or seals.

Remember that water can travel along pipes and surfaces, so the visible damp patch may not be directly beneath the source.

If you’re unable to locate the leak, avoid removing flooring or dismantling plumbing unnecessarily. A professional plumber can investigate further.

2. Check Whether You Can Turn Off the Water Supply

Knowing where your stopcock is located can make a significant difference when dealing with a leaking pipe.

In many homes, the internal stopcock is beneath the kitchen sink, inside a utility cupboard or near where the mains supply enters the property.

Turning it clockwise will usually shut off the mains water supply. Some fixtures also have individual isolation valves, allowing you to stop water flowing to a particular tap, toilet or appliance.

Don’t force a stiff or seized valve, and remember that turning off the mains won’t necessarily stop water already stored in tanks or heating systems.

If you’re unsure what to isolate, seek professional advice rather than attempting complicated adjustments.

3. Look for Signs of Hidden Water Leaks

Not every leak creates an obvious puddle. Some develop slowly behind walls, beneath flooring or inside cupboards.

Common warning signs include:

If you have a water meter, you can also check for unexplained usage. Turn off taps and water-using appliances, note the reading and check it again after a period without water use.

An unexpected increase could indicate a leak, although appliances and other factors may affect the result.

Persistent dampness doesn’t always mean a plumbing leak, but it’s worth investigating before further damage develops.

4. Check Your Boiler and Central Heating Pressure

If you’ve noticed water around a radiator, heating pipe or boiler, the problem may involve your central heating system rather than the mains water supply.

One possible warning sign is a boiler that repeatedly loses pressure. If your boiler has a pressure gauge or digital display, check whether the reading is lower than normal, using the manufacturer’s instructions as a guide.

A drop in pressure can sometimes indicate a leak, although other heating faults can produce similar symptoms.

Avoid repeatedly topping up the system without investigating the cause, and never remove your boiler casing or attempt internal gas appliance repairs.

If the problem involves your heating system, our boiler services and heating engineers pages explain the services we provide.

5. Take Photographs and Note the Symptoms

You don’t need to know exactly what’s causing the leak before contacting a plumber. However, a few useful details can help explain the problem.

Where it’s safe, take photographs of the affected area and make a note of:

For example, explaining that water collects beneath your bathroom sink whenever the tap runs is more useful than simply reporting a leak somewhere in the bathroom.

Clear information can help a plumber understand the symptoms and determine the appropriate next steps.

What Should You Avoid Doing When You Find a Leak?

Although it can be tempting to attempt a quick repair, the wrong approach may cause further damage.

Avoid:

A towel or container may temporarily catch dripping water, but it won’t resolve the underlying problem.

If water is near electrical sockets, switches or appliances, avoid contact with affected equipment. Where necessary, seek appropriate electrical assistance before using it again.

When Should You Call a Plumber About a Leak?

Some minor drips may allow time to arrange a convenient appointment, but certain warning signs should be addressed promptly.

Contact a professional plumber if:

Even a small leak can cause damage over time, particularly when water collects beneath flooring or behind fitted units.

If a ceiling is bulging or sagging due to water, keep clear of the affected area.

For homeowners and landlords in Heanor and surrounding parts of Derbyshire and Nottinghamshire, MD & BW Buxton Ltd provides plumbing repairs and maintenance.

We aim to attend on the same day or the following day where availability allows, although we don’t operate a dedicated emergency callout service.

Frequently Asked Questions About Water Leaks