Water pipe repairs and replacements
From the stop tap at the boundary of your property up to the connection inside your house: a single, seamless water supply replacement, less prone to splits and cracks.
External moling · Water main repairs · London
Lead pipe replacement, water supply repairs and leak detection across Greater London, using trenchless moling that passes under driveways, lawns and patios.
Approved, trained and insured for work on your water supply
How impact moling works
An old lead or steel pipe with a small bore. Low pressure at the taps, and more prone to leaks.
We dig a pit at the boundary stop tap and one by the house. Usually no more than 1 metre square and 1 metre deep.
A pneumatic piercing tool compacts and displaces the ground as it travels, under the driveway, lawn or patio.
A single new supply pipe from the boundary to the connection inside your house, with none of the risks of lead.
Disruption and reinstatement are minimal. Your garden and driveway stay as they were.
What we do
Specialists in water supply pipe repairs, replacements and lead pipe renewals within Greater London, for domestic, commercial and industrial clients.
From the stop tap at the boundary of your property up to the connection inside your house: a single, seamless water supply replacement, less prone to splits and cracks.
A pneumatic piercing tool creates the bore hole. The ground is compacted and displaced rather than excavated, so disruption and reinstatement are minimal.
Our moling equipment bores accurate, efficient channels for new pipe work without large scale excavation, saving time and money on water main replacements.
Leaking or burst pipes can turn into a disaster if not taken care of quickly. We offer a priority service whenever you find yourself dealing with one.
We supply and install all types and sizes of water main, plus a bespoke design service for smaller projects such as lead renewal, meter installations and diversions.
Design and installation of drainage systems for the private and public sectors, adhering to all of the relevant health and safety regulations.
Price estimator
Tell us about the job and see an estimate straight away. We confirm the final price after a free site visit, before any work starts.
Preview: these are example rates to show how the estimator works. Flow External Plumbing set their own prices before this goes live.
Send me this as a quote →Why moling

Old supplies, often lead, do not provide an adequate flow because of their smaller bore. A new pipe of 25mm or greater increases the pressure at your taps.
The mole burrows discreetly under gardens, patios and driveways, with no need for channels dug through your garden.
Our team have years of moling experience, for a lead pipe repair, a replacement, or an upgrade because of low water pressure.
We do the right job, at the right price, at a time that's right for you. We're happy to carry out a site inspection and discuss your options first.
Improved delivery to water dependent appliances helps reduce energy costs. Replacing a lead or steel supply can increase your water flow by up to 60%.
30 second check
Find the pipe where it comes into your home, usually under the kitchen sink by the internal stop tap, and answer three quick questions.
Was your home built before 1970?Lead was commonly used for water pipes until then.
Is the pipe dull grey, with swollen joints?Copper is bronze coloured; plastic is blue or black.
Scrape it gently with a coin. Shiny silver underneath?Lead is soft and marks easily.

Onsite case study
As this was a conservation area we needed multiple meetings with Thames Water, the Hampstead Garden Suburb Trust, the residents association and architects, providing detailed drawings, a method statement and a risk assessment.
The end result was the project being delivered on time and within budget.
How a job runs
One of our surveyors visits your property, takes precise measurements and explains the process.
A job can be won or lost at the planning stage. Potential issues are resolved and parts are ordered before we start.
Our installation and engineering teams arrive at the time agreed, on the pre-arranged date, and get to work right away.
If there are any issues down the line due to engineering faults, we repair or replace the work in line with our terms and conditions.
Recent works
Photos from our own jobs across London: small pits, new blue supply pipe, and surfaces put back.











Reviews
“As promised he was done in a day and barely left a trace. I wouldn't hesitate to recommend his services.”
“Karl did a great job with his moling equipment at my small terraced house.”
“It was a big job - a distance of almost 30 metres through hard ground the entire route and took almost two days. His work ethic, skill and attention to detail are impressive.”
“He carried out the moling work for us and did an exceptional job from start to finish. The work was completed to a very high standard, and everything was left incredibly clean and tidy.”
“Karl is excellent. Knowledgeable, friendly and reasonable prices. He was the only person we reached out to who came for a site visit and explained everything clearly. Recommended.”
“Very impressed with Karl's approach, knowledge and expertise in dealing with our mains lead pipe replacement. Completed in less than a few hours. Feel much safer drinking our tap water now.”
“Karl and his team are excellent. We had a water supply problem affecting 66 households. Karl was clear and communicative about what needed to be done and was very considerate to our residents.”
“He arrived on time, was very tidy and completed the job efficiently. Delight to deal with and would highly recommend.”
“All done in a day and for a reasonable price. Would highly recommend”
“He was very careful replacing our cobble driveway and stuck to the price that he had given which we felt was very reasonable.”
“Karl was very reliable, kept me well informed throughout the process, and followed up as promised as soon as the water company had completed their stage of the work.”
“Karl has been a pleasure to work with. Was very efficient and knowledgeable, especially when dealing with Thames Water. I would definitely recommend Karl and his team.”
“He was punctual, reliable, friendly and professional throughout.”
“Pure excellence! Incredibly professional! It was a pleasure having Karl's team over to do the job! The fee is fantastic too. Highly recommended!”
From client letters
“Within a week of the initial phone call the work was completed to a very high standard. Neighbours who saw the depth of the hole that you had to dig to get to the water main have commented that ‘you wouldn't have known your drive had been dug up’ as the block pavers were replaced to their original state (if not better)!”
“I was delighted that you were able to install the new inlet pipe by using the moling technology, thus avoiding excavating more of my driveway than the original inspection hole.”
“The work was carried out with the utmost efficiency. The finished job was of an excellent standard, and I was left with no mess at all.”
Google reviews are quoted from the Flow External Plumbing listing; letters are extracts published on flowxp.co.uk.
Where we work
Free quote
Tell us what is happening with your water supply. We're happy to visit, inspect the site and talk through your options before any work.