By the Flow Connects team · Last updated 17 April 2026 · 5 min read
TL;DR
- STC25 is the WRc Model Contract Document for Manhole Location Surveys; it defines the structure, not the software
- Legacy STC25-based tools remain in use but struggle with mobile capture, 3D output and modern client delivery
- Modern MH survey software captures STC25-compliant data while adding mobile workflow, auto-sketch, 3D and client portals
- Compatibility matters: any replacement should export STC25 datasets to water company and WRc-aligned formats
- The question isn't "STC25 or not", it's "STC25 with 2005 software or STC25 with 2026 software"
Key takeaways
- STC25 is a standard, not a specific tool; any competent MH survey platform supports it
- The choice isn't between STC25 and something else; it's between legacy software that only does STC25 and modern software that does STC25 and more
- Data export to STC25-compliant CSV or database formats is table stakes for any replacement platform
- The fields STC25 defines (manhole reference, cover level, invert levels, pipe details) remain the spine of UK drainage asset records
- Moving off legacy STC25 software doesn't mean losing your historic data; it means making it usable
In this article
- What STC25 actually is
- Why legacy STC25 software is falling behind
- What modern software builds on top of STC25
- Data compatibility: the migration question
- When legacy tools still make sense
- Frequently asked questions
Introduction
STC25 has been a fixture of UK drainage survey work for over 30 years. It's the WRc Model Contract Document for Manhole Location Surveys and Production of Record Maps, and it defines the data fields that a standard UK MH location survey should capture. Dozens of firms have built software around it, and many UK drainage contractors still work in tools that haven't had a UX refresh since the Windows XP era.
STC25 the standard is fine. It's doing its job. STC25 the software, in its older incarnations, is the part that's showing its age. Platforms like Flow Connects keep full STC25 data compatibility while bringing the workflow into 2026 with mobile capture, auto-sketch, 3D output and client portals.
Here's how to think about the choice.
What STC25 actually is
STC25 is published by WRc as a Model Contract Document. It's not a piece of software, it's a specification:
- The data structure of an MH location survey (manhole reference, cover level, depth, invert levels, pipe details, benching, construction, condition)
- The level of detail expected at each quality tier
- The format in which records should be delivered (typically a structured database export plus plan drawings and photographs)
- Compliance with water company adoption requirements under Section 104 and similar arrangements
When a UK water company asks for an STC25 survey, they're asking for data captured to that standard, delivered in a format compatible with their asset management systems.
Software built for STC25 is software that captures this data structure and exports it in the expected format. Several products do this well. The older ones do almost nothing else.
Why legacy STC25 software is falling behind
Legacy STC25 tools (some still in use across UK drainage firms) typically share a few traits.
Desktop-only capture. Field teams still use paper cards, then type the data into the desktop software back at the office. Two data entry steps, two chances for transcription errors.
Limited photo handling. Photos sit alongside records as file attachments rather than being tied to specific fields within the inspection. Cover photos, pipe photos and defect photos all end up in the same folder with manual naming conventions.
No 3D output. Legacy STC25 tools produce 2D CAD sketches and tabular records. For 3D chamber visualisation, firms traditionally relied on expensive laser scanners.
No client portal. The deliverable is typically a database file plus a printed or PDF report. Clients download, save locally, and the firm has no visibility of how the data is used downstream.
No mobile workflow. The surveyor in the field has no direct access to the STC25 database. All synchronisation happens through paper and manual data entry.
Poor integration with the rest of the business. RAMS, job planning, equipment tracking and CCTV all live in separate systems with no connection to the MH survey records.
These limitations are historical. Legacy STC25 software was built when desktop was the only environment, broadband wasn't universal, and client expectations were lower. The software did its job for the time. It's the time that changed.
💡 STC25 compatibility, 2026 workflow Flow Connects captures MH data to full STC25-compliant structure, exports to database and CAD formats water companies accept, and runs on mobile with auto-sketch, 3D and client portal on top. Start free on Flow Connects - test STC25 output on your next project →
What modern software builds on top of STC25
Modern MH survey platforms start with STC25 as the data backbone and layer capability on top:
Mobile field capture. The surveyor fills the STC25 fields on a phone or tablet at the chamber, with validation, required-field checks, and photo attachment per field. No paper intermediate step.
Auto-sketch rendering. The IC or MH sketch generates automatically from the structured STC25 data, removing 15-25 minutes per complex chamber of office drafting.
3D chamber models. The same STC25 data drives a 3D model that clients can rotate, measure and view in browser. No laser scanner required.
Client portal delivery. The finished deliverable is a portal link, not a database file. Clients log in, navigate to the asset on a map, open the inspection record, and see the 3D model alongside the STC25 data.
Integrated workflow. RAMS, job planning, equipment tracking, CCTV records and client reporting all link back to the same project and the same assets. One pane of glass instead of eight.
API-first data access. Structured data is available via API for integration with client systems, GIS platforms, adoption bodies and asset management tools.
The STC25 data structure is preserved in all of this. A water company asking for an STC25-compliant deliverable gets exactly that. The internal workflow leading to it is the part that's modernised.
Data compatibility: the migration question
The question most firms ask when thinking about moving off legacy STC25 software is: "What happens to 15 years of historical data?"
The good answer is: it comes with you, and it becomes more useful. Modern platforms typically:
- Import legacy STC25 database exports (DBF, CSV, SQL dumps depending on source)
- Preserve the original record structure while mapping to the new platform's fields
- Re-link photos and drawings where file references are intact
- Flag records with missing or malformed data so they can be cleaned up rather than silently corrupted
The migration isn't instant. A typical UK drainage firm moving 10,000-50,000 historical MH records will spend 2-6 weeks on data migration, depending on how clean the source data is.
Once migrated, the old data becomes queryable in ways it wasn't before. Searching 15 years of MH records for every chamber over 4 metres deep, or every chamber with "collapsed benching" in the notes, is a minute's work in a modern platform. In legacy STC25 software, it's typically impossible.
When legacy tools still make sense
Legacy STC25 software isn't always the wrong choice. It still makes sense in specific circumstances:
- Very small firms (1-3 people) doing fewer than 10 MH surveys a month, where the overhead of platform adoption exceeds the benefit
- Firms whose clients explicitly require delivery in a specific legacy format that newer platforms don't match
- Firms with deep custom workflows built on top of specific legacy tools where migration cost is prohibitive
For the majority of UK drainage contractors (15+ staff, doing regular MH survey work, with clients who are increasingly asking for portals and 3D output), legacy STC25 software is a deprecating tool chain.
Frequently asked questions
Is STC25 being replaced as a standard? No. STC25 remains the WRc Model Contract Document and is still the UK reference for MH location surveys. What's changing is the software used to produce STC25-compliant deliverables, not the standard itself.
Can water companies accept digital-first MH survey deliverables? Yes, provided the data structure matches STC25 requirements. Most UK water companies now explicitly support digital delivery (structured database, CAD and portal access) alongside traditional PDF and printed formats.
Does modern MH software support the full STC25 field list? Reputable platforms support all core STC25 fields and typically add more (geolocation, detailed condition ratings, pipe material catalogues, benching variations). The standard is the floor, not the ceiling.
What format should STC25 data be delivered in? Depends on the client. Water companies typically accept CSV, DBF or direct database integration. Private clients typically accept CAD (DWG/DXF) plus a PDF report. Modern platforms export to all of these from the same underlying record.
Do I lose anything by migrating from legacy STC25 software? If migration is done properly, no. Historic records, photos and drawings transfer with the data. What you lose is the user interface pattern your team is familiar with, which is a short-term retraining cost.
How long does a typical STC25 platform migration take? For a firm with 10,000-50,000 historical records, allow 3-6 months end to end. Most of that is data cleaning, not the technical migration. The smaller and cleaner your source data, the faster it goes.
STC25, modernised
STC25 the standard is doing its job. STC25 in 20-year-old desktop software is slowing your business down. The right question to ask when looking at MH survey software isn't whether to support STC25, it's whether the tool does STC25 and everything else your 2026 operation needs.
Flow Connects captures and exports full STC25-compliant MH data, with modern mobile capture, 3D output and client portal included as standard.
Start free on Flow Connects - run an STC25-compliant inspection today →
Sources:
- WRc Model Contract Document for Manhole Location Surveys (STC25)
- Water UK Sewerage Sector Guidance (SSG)
- Section 104 adoption guidance (water companies)
Disclaimer: This article is general guidance for UK drainage and utility survey professionals. STC25 requirements vary by water company and client; always verify the specific delivery format required for each project.
Internal link suggestions:
- /blog/manhole-inspection-software-3d-uk-guide (Pillar 1)
- /blog/auto-sketch-inspection-chamber-software (Spoke 1.1)
- /blog/all-in-one-survey-platform-uk-2026 (Pillar 3)
Image suggestions:
- Hero: Side-by-side of legacy STC25 interface vs Flow Connects mobile capture (alt: "Legacy STC25 software versus modern mobile MH survey capture")
- Mid-article: STC25 data structure with modern overlays (3D, auto-sketch, client portal) (alt: "STC25 data structure extended with modern features")