Bs 8558 Pdf May 2026

BS 8558 adopts the five fluid categories from the Water Regulations:

| Category | Description | Example | Required protection | |----------|-------------|---------|----------------------| | 1 | Wholesome water | Drinking water | None (system inherent) | | 2 | Aesthetic change | Slightly warm, discolored | Single check valve | | 3 | Low health hazard | Water with detergent | Double check valve or RPZ | | 4 | Significant health hazard | Chemically contaminated | RPZ (Reduced Pressure Zone) | | 5 | Serious health hazard | Sewage, pathogens | Air gap with overflow (A or AB type) |

The standard gives specific design guidance for each category, including minimum air gap dimensions (e.g., 20 mm or twice the inlet diameter).

Health & Safety Executive (HSE) guidance (often called ACoP L8) references BS 8558 for technical water system design. The standard details: bs 8558 pdf

This is a frequent point of confusion.

For example: BS EN 806 mentions backflow prevention generally. BS 8558 gives you the exact fluid categories (1 to 5) and shows you which mechanical device (e.g., a verified RPZ valve) is required for a Category 5 risk like a hospital dialysis unit.

If you design water services without referencing BS 8558, a local water authority (e.g., Thames Water, United Utilities) can reject your application for a new connection. BS 8558 adopts the five fluid categories from

Many users accidentally search for related but different standards:

| Search Term | Actual Standard | Relevance | |-------------|----------------|------------| | BS 8558 pdf | Guide to water supply in buildings | ✅ Correct | | BS 8558 2011 pdf | Withdrawn version (superseded by 2015) | ❌ Obsolete | | BS 8558 pdf free | Likely illegal or outdated draft | ⚠️ Dangerous | | BS 6700 pdf | Replaced by BS 8558:2015 | ❌ Not current | | BS EN 806 pdf | European mandatory standard (not UK-specific) | ⚠️ Use alongside BS 8558 |

Always verify the year. BS 8558:2015 remains current (as of 2025). Check the BSI website for any amendments. For example: BS EN 806 mentions backflow prevention

Search official standards suppliers or national standards body (BSI) for the BS 8558 publication or guidance documents; local planning authorities and water companies often publish practical summaries and supporting PDFs. (I did not include direct links.)

Engineers, plumbing designers, and building services professionals frequently search for a “BS 8558 pdf” because this standard is a cornerstone of UK water hygiene and safety. It is the successor to BS 6700 and, together with the Water Supply (Water Fittings) Regulations 1999, forms the technical backbone for domestic water services in buildings. This paper provides a deep analysis of its contents, applications, and regulatory context—without distributing copyrighted material.