Mains Water Leak Detection

Mains water leak detection is a job for specialist leak detection experts. 

There are symptoms of a Leak to look for and tests you can carry out before you need our expert mains water leak detection service.

  • Signs and symptoms to look for inside and outside your home
  • Simple DIY Leak Tests using your Stopcock and water main Valve to confirm a leak exists on your property.
  • Our Techniques to locate leaks on water mains pipes.
  • Water Supply Mains Leak Repair Service
ADI Leak Detection have been detecting water mains leaks since 2011. Our nationwide network of plumbing engineers are some of the most experienced and knowledgeable in the country.

Mains Water Leak Detection

What are the signs of a leaking water main?

Signs of a mains water leak can be present outside, inside your property or not visible at all. 

A mains leak will cause a spike in your water consumption which will lead to a high water bill. High water usage may lead to a section 75 notice from your mains water supplier.

There are many causes of water mains leaks, the responsibility for leaks varies.


  • Low incoming water pressure with the stopcock or valve fully open.
  • Water meter constantly spinning when no water is being used in your property.
  • Increased levels of humidity, condensation or a damp smell in a room.
  • A sudden increase in water softener salt without higher water consumption.
  • Mould, Damp, Mildew or water damage to floors, and walls.


  • Hissing or gurgling sounds from the incoming water mains pipe.
  • Surface water puddles or flooding with no obvious reason.
  • Subsidence or boggy ground without an explanation.
  • An area of grass or garden growing faster than the rest of the lawn.

You can confirm you actually have a leak or leaks by carrying out some DIY leak tests.

DIY Water Mains Leak Tests

DIY mains water leak tests will reveal if a water supply pipe is leaking.

Method & Whats RequiredSteps to take 

Water Meter Leak Test

You will need access to the Internal Stopcock, Mains Water Meter and stop valve at the property.
  1. Turn off your internal stop cock. The stop cock is usually located on the inside of an exterior wall.
  2. Locate the external stop valve for your property. The stop valve is located next to the water meter under a metal or plastic cover at the property boundary. The cover will be labeled “WATER”, “W” or “WATER METER”.
  3. Open the cover then turn the tap or valve to the off position. 
  4. Record the water meter reading.
  5. Wait 30 minutes
  6. Take a second water meter reading
You have a water leak if the second reading from the water meter is higher than the first reading.

Syphonic Cup Test

You will need two people, a pint-sized glass, and a water shut-off key (i.e. a toby key).

  1. One person fills the glass full of water from the cold water tap. Keep the end of the tap submerged under the water inside the glass for the duration of the test.
  2. The other person now needs to turn of the mains water supply at the external water meter /valve using a water shut-off key (Toby key). 
  3. Monitor the water level inside the Glass for the next 5 minutes.
You have a water leak if the water level inside the glass falls. A leaking in the water main will syphon the water from the glass back into the supply pipe.

If these tests confirm you have a leak then it’s time to call the expert leak detectives. Our engineers locate water mains leaks using non-destructive methods.

How Does ADI Leak Detection Find Water Supply Leaks?

Our expert leak detection technicians use advanced non-destructive techniques to locate leaks on water main supply pipes. The depth of water mains pipes can affect the leak detection process.

  • Thermal imaging cameras are used to identify areas of damp flooring.
  • Acoustic ground microphones are used to listen for the sound of water escaping from pipes.
  • Hydrogen / Nitrogen Tracer Gases are used to in conjunction with a gas sensor and acoustic listening devices to confirm the location of the leak.
  • Ferret Leak Detectors and a Leak Correlation are available to aid the process of pinpointing a water supply pipe leak.
Our water mains engineers provide nationwide same day leak detection and repair service. We provide insurance-approved reports to assist with your insurance claim.

Can you repair water mains leaks?

Water mains repairs can be carried out on the same day, if time allows.
Our fixed price leak detection service covers the cost of tracing the source of the leak.
A fixed price is given at the quotation stage for any repairs that can be carried out on the same day.

Leak repairs by our qualified and experienced plumbers are covered by our workmanship guarantee.


Our Reviews & Accreditation’s

Leak on a LEAD pipe supplying some flats!
CIPHE - Chartered Institute of Plumbing and Heating Engineering

ADI Leak Detection is accredited with The Chartered Institute of Plumbing and Heating Engineering.

ADI Leak Detection is registered with The Water Industry Approved Plumbers’ Scheme.

ADI Leak Detection is registered with The Water Industry Approved Plumbers’ Scheme.

ADI Leak Detection is a Watersafe Accredited contractor.

Contact ADI Leak Detection For Help With Water Mains Supply Leaks

ADI Leak Detection specialises in locating and repairing water leaks. Our underground water mains expertise set us apart from other leak detection companies.

We are proud to be the UK’s leader in non-invasive water leak detection services, with over 700 Trustpilot reviews!

If you suspect a water leak at your property, call the ADI team today. Our skilled team can carry out leak detection and often provide cost-effective repairs on the same day.

ADI Leak Detection Customer Service Team

Adrian Morgan

Adrian Morgan CIPHE RP RHP is the founder & Managing Director of ADI Pro Leak Ltd. Adrian is also the Head Plumbing, Heating & Leak Detection engineer at ADI Leak Detection.

Adrian CIPHE RP RHP is proud to be registered with the Chartered Institute of Plumbing & Heating Engineering, a Registered Plumber and a Registered Heating Professional.