Service plans show the recorded positions of buried utilities such as gas, electricity, water, and telecoms. However, these plans are not always accurate. Services may have been diverted, incorrectly recorded, or installed since the plan was issued. Understanding how to read service plans and recognising their limitations is essential before any excavation work begins on site.
Key Hazards
Cable or pipe strike from relying solely on inaccurate or outdated plans
Failure to identify all services present due to incomplete plan coverage
Misinterpreting plan symbols leading to digging in the wrong location
Unrecorded private services not shown on any statutory utility plan
Control Measures
Obtain up-to-date service plans from all statutory utility providers before any excavation.
Cross-reference plans from multiple providers to build a complete picture of buried services.
Learn the standard colour coding and symbols used on utility service plans.
Treat all plan information as indicative only; always verify positions using CAT and Genny scans.
Mark the indicated positions of services on the ground using the correct colour spray paint.
Brief the excavation team on all services shown on the plans and their approximate positions.
Allow for a 500mm tolerance zone either side of the indicated service position.
Request additional plans for private services such as estate lighting and on-site drainage.
Keep a copy of all service plans at the excavation location for reference during work.
Remember
Service plans are indicative only and must always be verified with CAT and Genny scans
Obtain plans from all statutory utility providers before any excavation work begins
Mark indicated service positions on the ground using the correct colour spray paint
Allow a 500mm tolerance zone on either side of every indicated service position
Private services may not appear on statutory plans; request additional information separately
Applicable Legislation: New Roads and Street Works Act 1991 · HSG47 (Avoiding Danger from Underground Services) · CDM 2015 · PAS 128 (Underground Utility Detection)