Water Main Survey

A burst or damaged water main isn’t just a repair job, it can mean flooding, water pressure loss, and unplanned repair costs. Before excavation, drilling or piling work begins, knowing exactly where water mains run beneath your site lets you plan around them with confidence, rather than finding out the hard way.

Why it’s important to Locate Water Mains

Water mains vary in size, depth and material depending on their age, and older pipework in particular isn’t always accurately recorded on utility plans. Striking a water main during excavation can cause significant water loss, damage to surrounding ground and structures, and service disruption for properties relying on that supply, sometimes affecting a much wider area than the immediate site. A water main survey removes the guesswork, giving your team confirmed information on pipe position and depth before the first cut is made.

How We Locate Water Mains

Our surveyors use a combination of electromagnetic detection and GPR to trace water main routes, adapting our approach to the pipe material and ground conditions on your site. Metallic water mains can often be traced using electromagnetic detection, while plastic or non-metallic pipework, increasingly common in newer installations, requires GPR to detect, since it won’t carry the electromagnetic signal that metallic pipes do. Combining both methods means we’re not relying on a single technique that could miss certain pipe types entirely.

Planning With Confidence

Following a survey, you’ll receive a report and drawing showing the location and approximate depth of water mains identified across the site, along with any other buried services detected during the same survey. This gives your project team a clear, reliable reference for planning excavation, drilling or piling work, rather than working from assumptions or incomplete records that may not reflect what’s actually in the ground.

Why Choose Subvision for Water Main Surveys?

Subvision Surveys is SSIP and ISO accredited, with a team of over 25 surveying professionals delivering water main and Buried Gas Main Surveys for contractors, developers and utility providers across London, the South East and nationwide.

Contact Subvision Surveys today to discuss your water main survey requirements, or speak to one of our experts on 0333 920 942.

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Water Main Survey FAQ’S

 

Water mains vary in size, depth and material depending on their age, and older pipework isn’t always accurately recorded on utility plans. Striking a water main during excavation can cause significant water loss, damage to surrounding ground and structures, and service disruption for properties relying on that supply, sometimes affecting a much wider area than the immediate site. Repairing a damaged main also brings work to a halt while the issue is addressed, adding cost and delay to a project that could largely have been avoided with a survey carried out in advance.

 

Yes. Metallic water mains can often be traced using electromagnetic detection, which follows the signal given off by metallic pipework, but plastic and other non-metallic pipes, increasingly common in newer installations, won’t carry that same signal. For these, we use Ground Penetrating Radar, which detects changes in the ground itself rather than relying on a conductive material. Combining both electromagnetic detection and GPR means we’re not limited to only finding metallic pipework, giving a more complete picture of water main routes regardless of the material used.

Accuracy depends on ground conditions, pipe depth and material, as well as the experience of the surveyor interpreting the results. Our surveyors use a combination of electromagnetic detection and GPR, adapting the approach to suit the specific site and pipe type, which improves reliability compared to relying on a single detection method. While no non-intrusive survey can guarantee absolute certainty in every ground condition, combining methods and drawing on experienced interpretation gives you a strong, reliable indication of pipe position and depth before excavation begins.

You’ll receive a report and drawing showing the location and approximate depth of water mains identified across the site, along with any other buried services detected during the same survey. This gives your project team a clear, reliable reference for planning excavation, drilling or piling work, rather than working from assumptions or incomplete records that may not reflect what’s actually in the ground. The information is presented in a format your contractors, engineers or project managers can use directly when planning groundworks.

Yes. Subvision Surveys often combines water main surveys with wider GPR surveys and PAS128 utility mapping, giving clients a fuller picture of a site’s underground infrastructure beyond just water mains. Because we carry out all these services in-house, this doesn’t mean coordinating between separate providers, our own team applies whichever combination of detection methods best suits your site. This is particularly useful on sites with multiple utility types present, where understanding the full picture of buried infrastructure matters more than focusing on a single service in isolation.

Water main surveys are used by contractors, developers, utility providers and local authorities ahead of excavation, construction or infrastructure work of any kind. Whether it’s a small residential extension or a large commercial development, understanding the position of water mains is an important part of planning groundworks safely and avoiding unexpected disruption once work is underway. Water companies and utility providers themselves may also require a survey ahead of maintenance or upgrade works to existing mains infrastructure, where accurate positioning is essential before any excavation takes place.

Have Any Questions?

If you have any questions regarding our services feel free to contact the Subvision team.