Topographical Survey Harrow: What You Need
A topographical (topo) survey in Harrow (HA1 and HA2) maps the natural and man-made features of your land, including levels, contours, and boundaries — all tied to Ordnance Survey National Grid coordinates.
What Is Included in a Topographical Survey
| Category | Specific Features Surveyed | | --- | --- | | Terrain | Ground levels, spot heights, contours (typically 0.5m or 1m interval) | | Natural features | Trees with position and canopy, vegetation, water bodies, streams | | Man-made features | Building footprints and heights, fences, walls, boundaries, roads, paths, driveways | | Drainage and utilities | Manholes, gullies, drainage covers, visible utility markers, street furniture | | Georeferencing | OS National Grid coordinates (essential for planning and engineering) |
Not included: Underground or buried features — requires a separate utility survey with GPR.
2025 Costs in Harrow (HA1 and HA2)
| Site Size | Typical Use | Cost (ex VAT) | | --- | --- | --- | | Up to 0.25 acres | Residential plot, small garden | £350–£600 | | 0.25–0.5 acres | Medium residential | £795–£900 | | 0.5–1 acre | Commercial site, small development | £995–£1,200 | | 1–3 acres | Larger development | £1,500+ | | Minor survey (quick) | Small garden or land | ~£300 | | Day rate (8–10 hours) | Typical-sized site plus drawings | £500 |
Typical Deliverables
| Deliverable | Format | | --- | --- | | 2D CAD drawings | AutoCAD DWG at 1:200 or 1:500 scale | | PDF plans | For planning applications | | Contour lines and spot levels | With annotations | | 3D model or DTM | Digital Terrain Model — often in Revit or BIM format | | Optional: 3D point cloud | From laser scanning |
Key Questions When Comparing Quotes
- Is OS National Grid tie-in included?
- What contour interval (0.5m vs 1m)?
- Are invert levels for drainage included?
- Is travel included in the price?
- What equipment is used (total station, GPS, drone)?
When You Need a Topographical Survey in Harrow
| Project | Topo Survey Required? | | --- | --- | | Planning permission | Yes — required by Harrow Council for most developments | | New development | Yes — site layout and drainage design | | House extension | Required for sloping sites or complex boundaries | | Drainage and SuDS design | Yes — levels and drainage features | | BS5837 tree surveys | Yes — tree positions and RPAs for planning | | Rights to light | Yes — accurate levels for daylight assessment |
Timeline
| Stage | Duration | | --- | --- | | Site visit | 1–3 working days for most standard sites | | Drawing delivery | Within 1 week of survey | | Total | 1–2 weeks from instruction |
Frequently Asked Questions
Q: What accuracy is achieved on a topographical survey in Harrow?
±10–15mm for terrestrial surveys using total station or GPS. Surveys are tied to OS National Grid coordinates.
Q: What scale are drawings produced at?
1:200 or 1:500 for planning submissions. Confirm with your architect or Harrow Council planning department.
Q: Does a topographical survey include underground drainage?
No — underground or buried features require a separate GPR or drainage survey. Confirm scope with your surveyor.
Q: Can the survey include drone data?
Yes — drone LiDAR available as an add-on for large or complex sites.
Q: Is the survey georeferenced?
Yes — all surveys are tied to Ordnance Survey National Grid (OSGB36) and Ordnance Datum Newlyn (ODN).