A site visit, or a more formal audit for higher-risk or higher-volume products, is where paper claims about a manufacturer's capability and quality systems get tested against what's actually happening on the floor. This guide sets out what a useful visit or audit should cover.
Key points
- A site visit should happen before committing to any significant or ongoing production relationship.
- Look at equipment, quality systems, documentation practices and general site discipline together, not any single area in isolation.
- Meet the technical and quality team directly, not just a sales contact.
- For higher-risk products, a formal audit with a documented checklist is worth the additional time.
Facilities and Equipment
Check that equipment matches what was described during quoting, that maintenance and calibration records are available and current, and that environmental controls - temperature, humidity, contamination prevention - suit your specific product's requirements. For hazardous or regulated production, confirm site permits and, where applicable, COMAH status - see COMAH manufacturing sites.
Quality Management System in Practice
Ask to see how the quality system actually operates day to day - batch record review, deviation logs, and how customer complaints are tracked and resolved - rather than relying on certification alone. A functioning internal audit programme and evidence of continuous improvement are stronger indicators of genuine quality culture than a certificate on the wall.
Documentation and Traceability
Review batch record examples, certificate of analysis formats, and how retained samples are stored and tracked - see batch traceability and retained samples. Good documentation practice is one of the clearest, most checkable signs of overall operational discipline.
Meet the Technical and Quality Team
A site visit is the opportunity to meet the people who will actually be responsible for your product - the technical lead and quality manager, not just a commercial contact. Their depth of knowledge and willingness to discuss process detail candidly is a useful signal in itself.
General Site Discipline
Housekeeping, labelling clarity, and general organisation on the production floor are informal but genuinely useful indicators of how carefully a site is run. A well-run site tends to look and feel orderly; a poorly controlled one often shows it, even before any formal issue is documented.
When to Use a Formal Audit Instead of a Visit
For higher-risk products - hazardous materials, regulated end markets, or high commercial value - a more structured audit against a documented checklist is worth the additional time compared with an informal visit. This typically covers the same areas in more depth, with a written report and follow-up on any findings.
Questions to Ask During a Visit
- Can we see a recent batch record and certificate of analysis for a similar product?
- How are deviations and customer complaints tracked and resolved?
- Who will be our direct technical and quality contacts once we're in production?
- What was the finding and outcome of your most recent internal audit?
What to Look At
A site visit tells you things documentation cannot. General order and housekeeping are a reasonable proxy for how the operation is run. Look at whether materials are properly labelled and segregated, whether records are being completed as work happens rather than retrospectively, and whether the plant you would actually use is in good condition rather than the showcase area.
Ask to see the specific vessels, filling lines and storage your product would use. A general tour of an impressive site tells you less than seeing the equipment that would run your work, which may be older or busier than the parts shown by default.
Testing the Systems
Two exercises are worth doing in person. Ask them to trace a past batch back to its raw material lots, and to identify which batches used a given lot - how quickly and confidently they manage it tells you what would happen in a real incident, see batch traceability. And ask what else runs on the equipment your product would use, and how cleaning between products is validated.
Also worth asking: how deviations and out-of-specification results are handled, how changes are controlled, and how customer complaints are investigated. The answers reveal quality culture more reliably than any certificate does - though checking the scope and accrediting body of certificates is still worth a few minutes, since scope is sometimes narrower than assumed.
Frequently Asked Questions
Is a phone or video call ever an adequate substitute for a site visit?
For very low-risk, low-volume work it might suffice initially, but for any significant or ongoing relationship an in-person visit reveals things a call cannot.
Should we pay for a formal third-party audit?
For high-risk or high-value products, a professional audit can be worth the cost, particularly if you lack in-house expertise to assess a manufacturer's systems rigorously yourself.
What's a warning sign during a site visit?
Reluctance to show documentation, evasive answers about quality issues, or a mismatch between what was described at quoting stage and what's actually on site are all worth treating seriously.
Related Guides
Last reviewed: August 2026. Regulation and guidance change — verify anything you rely on against the primary source. Tell us if something here is out of date.
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