Comfort Services Group, a leading water treatment company in the UK, is committed to offering information and complementary guidance to BS EN standards on how to correctly design, maintain, and operate systems supplying water for domestic use within buildings and their curtilages. This document specification from 2015 outlines how we can help provide safe, efficient systems with proper knowledge to match consumption needs and ensure compliance with BSI regulations. Here, we publish a clear overview to help you get in touch for expert support.
What is the BS 8558 Standard?
BS 8558 is a British Standard that gives guidance on designing, installing, checking, and maintaining water supply systems inside buildings. It works with BS EN 806 parts 2, 4, and 5 and offers advice to prevent contamination and system failure. It is all about making sure tap water is pure, safe, and available whenever people need it. This standard also describes how to manage services supplying water, maintain hygiene, and protect public health by following clear steps and requirements.
Here’s a short guide to what BS 8558 covers:
- Scope: This part defines the systems and buildings it applies to, like homes, flats, workplaces, and shared blocks. It’s useful for domestic water use and sets clear boundaries.
- Normative references: This section lists important documents you need alongside BS 8558, such as BS EN 806 parts 2, 4 and 5, safety rules, and other standards necessary to follow.
- Terms and definitions: Defines key words in the document so everyone understands the same meaning, keeping the wording consistent and clear.
- Guidance to BS EN 806 -2: Gives notes on performance requirements, materials, sizing, water storage, and protection against contamination as per BS EN 806-2.
- Guidance to BS EN 806 -4: Offers tips for installation, pipe support, connection methods, and testing, in line with BS EN 806-4.
- Guidance to BS EN 806 -5: Helps with maintenance planning, inspection schedules, and sample points per BS EN 806-5 to keep systems safe and hygienic.
What Does BS 8558 Cover?
BS 8558 explains how to design safe water systems in domestic buildings. It covers choosing the right materials, sizing pipes correctly, testing for leaks, and disinfecting before people use the water. Our specification uses clear steps and helpful diagrams to guide installers and owners. It covers hygiene, prevention of bacterial growth, system flushing, tank cleaning, and how to check that the water meets quality standards. We give you confidence in your system’s work and safety.
Guide for Water Installation
BS 8558 details the correct choice of materials for water supply in order to maintain proper hygiene and optimal functionality.
These include:
- Copper: A durable metal with natural antibacterial properties. Copper pipes resist corrosion and help keep water clean. It’s ideal for hot and cold supply lines and lasts many years if installed well.
- Stainless steel: Very strong and corrosion‑free. It’s often used in systems where durability and low contamination risk are key, such as in commercial kitchens or medical facilities.
- Steel: Usually coated or lined to resist rust. Steel is strong and used for larger systems. It needs internal lining or galvanising to stop corrosion.
- Some plastics: Materials like PEX and MDPE offer flexibility and are easy to work with. They are suitable for both hot and cold water, and resist many common contaminants, but must meet safety specs.
When to Use BS 8558?
BS 8558 is applied in several situations where water systems need to be safe and reliable.
- Newly Installed Water Systems: Right after installation, systems are empty and may hold debris or bacteria. BS 8558 guides how to flush, check, disinfect, and test everything before water goes to taps.
- Renovations and Upgrades: When parts of the system are changed—like pipes moved or replaced—it’s vital to check those sections, clean and disinfect them, and ensure they are safe. BS 8558 shows how to do that step by step.
- Post-Maintenance: After any repair or check, parts might be opened or drained. BS 8558 says how to restart safely, including proper flushing, testing, and documenting work to maintain hygiene and prevent issues.
- Commissioning of Systems: Before a new or upgraded system is used, it must be commissioned. That means testing pressure, flow, temperature, and disinfection. BS 8558 provides clear checklists and information on how to complete this process.
- Legionella Risk Management: BS 8558 helps prevent Legionella by controlling water temperature and avoiding stagnation. The standard shows how to choose materials and system layouts that lower risk and keep water safe from bacteria.
BS 8558 and Other Related Regulations and Standards:
- Building Regulations and Water Supply Regulations: BS 8558 supports Building Regulations that cover water installations in buildings. It also aligns with Water Supply (Water Fittings) Regulations by ensuring fittings and pipework do not waste or contaminate water.
- British Standards: BS 8558 works tightly with other standards. It adds complementary guidance to BS EN 806, BSI specifications, and documents. Together, they form the full specification guide for designing, installing, and maintaining safe water systems inside buildings.
Who is BS-8558 Relevant for?
The standard should be applied by:
- Anyone involved in the design, installation, testing, operation, and maintenance of services (businesses with water storage facilities)
- Water companies
- Product manufacturers
- Installers of water supply services in the UK.
We at Comfort Services Group use our knowledge to help all of these groups understand and apply BS 8558 correctly.
Why Use BS‑8558 Standard?
BS 8558 helps to avoid key water safety problems. It targets these main risks:
- Managing stagnation of water in pipes, cisterns, and other storage vessels, which can lead to contaminants and bacteria growth.
- Keeping water temperatures within the range of 20 °C to 45 °C to prevent bacteria like Legionella from growing.
- Avoiding the use of materials with the greatest potential to harbour or provide nutrients for bacteria and other organisms, materials must meet hygiene specs.
- Avoiding installation of fittings where aerosol formation can occur, such as spray taps or showerheads, which can spread bacteria if water quality is poor.
By following BS 8558, risks are reduced, water quality is maintained, and public health is protected.
Standard BS 8558 & Legionella
BS 8558 supports Legionella control. It shows how system layout, temperature control, flushing, and disinfection work together to lower Legionella risk. Proper system design avoids areas where water sits still. Regular checks, monitoring, and correct documentation are all included. We help you follow BS 8558 steps, from design to monitoring, to reduce the risk of Legionella in domestic water systems.
Tank Cleaning and BS 8558
BS 8558 advises on cleaning tanks to stop contamination. Tanks should be inspected regularly, cleaned and drained fully, with loose sediment removed. Surfaces must be brushed and flushed with clean water. All work needs to be documented with dates, findings and corrective actions recorded. Tanks that feed multiple outlets must be cleaned more often. This regular maintenance of services supplying water is key to safe water.
Water Testing and BS 8558
Testing is essential after installation, maintenance, or suspected issues. BS 8558 explains sample points, testing methods and frequency. It covers tests for bacteria, chemical content, temperature and pressure. Results need to meet national standards. Any failure must be fixed and retested. The standard helps maintain a record of tests and their results. This knowledge and information is important to show compliance.
BS 8558 and Disinfection
BS 8558 gives guidance on flushing and disinfection:
- When to implement flushing: Flush pipes when systems are idle for long periods or after repairs. Flushing helps remove sediments and stale water. Clean water then flows before moving to disinfection.
- Flushing before disinfection: Always flush before starting disinfection. This removes loose dirt and helps the disinfectant reach every part of the system. It boosts the process’s effectiveness.
- Disinfection: Use methods such as chlorination at correct doses for correct contact times. All parts must be treated. Then flush again to remove disinfectant and any residues. Test the water again to confirm the system is safe.
BS 8558 and Chlorination
Chlorination is a common disinfection method recommended by BS 8558. It uses chlorine to kill microbes in pipes and tanks. The standard explains how to choose dosing levels, how long to leave chlorine in the system, how to flush it afterwards, and then how to test to be sure everything is thoroughly clean. We help you apply chlorination safely and effectively as part of BS 8558 compliance.
How Comfort Services Group Can Help Ensure Your Compliance With BS 8558 Standard
We at Comfort Services Group have deep knowledge of BS 8558 and related BSI standards. We help from start to finish: system design, installation guidance, material choice, commissioning support, routine testing, flushing, tank cleaning, and disinfection. Our engineers use the spec from BS EN 806 and provide document records, publish reports, and offer continuous maintenance of services supplying water. You can rely on our expertise for complementary guidance to BS EN standards and BSI approval. Get in touch to help protect health and ensure compliance.
FAQs
What’s changed since the last update of BS 8558?
Since the 2015 update, BS 8558 has added more detailed advice on material selection, risk control, and documentation. It now aligns closely with BS EN 806‑2, ‑4, and ‑5 and includes fresh guidance on Legionella management, flushing schedules, and new testing protocols. The document emphasises water safety and links with BSI and building regulations to publish thorough standards.
Is BS 6700 still current?
BS 6700, which covered the design and installation of water systems, has been superseded. Its content is now part of BS EN 806 and BS 8558. BS 8558 takes over its role for domestic water design, focusing more on hygiene, Legionella control, and documentation under the wider EN standard framework.
What does BS 6700 cover?
BS 6700 was a standard on design, installation, commissioning and maintenance of domestic water supply systems. It covered water quality, system layout, drainage, pressure and thermal performance. This content is now integrated into BS EN 806 and BS 8558, so all its guidance lives on under those modern standards.
We are proud to share our experience and knowledge and take pride in offering this to all clients when required. If I, or one of the team can help then please schedule a meeting via the office or get in touch via one of our social media platforms.
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