Domestic water systems maintenance.

Service provided by:

Our services

What is domestic water systems maintenance?

Domestic water systems maintenance is the process of keeping water systems clean, safe, and compliant through regular inspection, monitoring, and treatment. It ensures that cold and hot water systems, storage tanks, and associated pipework remain free from contaminants, scale, and harmful bacteria such as Legionella.

At Complii, we provide comprehensive maintenance programmes that combine routine monitoring, cleaning, disinfection, and refurbishment with advanced water quality control systems. Our work aligns with ACoP L8 (4th Edition), HSG274, and BS 8558, ensuring every system is maintained to the highest standard of safety and compliance. Whether you manage a commercial building, healthcare facility, industrial plant, or residential property, we help you maintain reliable, hygienic, and legally compliant water systems.

We're an accredited contractor

Why choose Complii?

How we can help.

Protect your people, property, and business. Here’s why we’re the right choice for domestic water systems maintenance.

Improved water quality

Regular maintenance prevents the build-up of scale, debris, and biofilm, ensuring clean, safe water that meets quality standards and user expectations.

Reduced Legionella risk

By maintaining water temperature, circulation, and cleanliness, you minimise the conditions where Legionella bacteria can grow, protecting users from potential infection.

Full compliance with UK regulations

All works are carried out in accordance with ACoP L8, HSG274, and BS 8558, giving you complete assurance that your systems meet legal and health requirements.

Reliable system performance

Routine inspections and cleaning prevent corrosion, blockages, and inefficiencies, helping your system perform consistently and reducing the likelihood of costly failures.

Clear documentation and assurance

We provide detailed records, sampling data, and maintenance reports that demonstrate compliance and support your site’s water safety plan.

Tailored maintenance programmes

Every site is different. Our engineers design bespoke maintenance schedules based on system type, building use, and risk level, ensuring your approach is both effective and efficient.

Your questions answered.

Typical systems include cold water storage tanks, calorifiers, water heaters, pipework, cooling towers, evaporative condensers, and domestic water distribution systems.
Cold water storage tanks should be inspected and sampled annually, or more frequently if the inspection deems it necessary. Hot and cold water outlets should typically be sampled every six months as part of your water safety plan.
Yes. Regular microbiological sampling and quality audits are part of HSG274 and BS 8558 requirements, ensuring your system remains within safe and compliant limits.
Under the Health and Safety at Work etc. Act and ACoP L8, the dutyholder or responsible person must ensure systems are properly managed, maintained, and monitored to control the risk of Legionella.
If sampling indicates contamination, corrective action such as disinfection or system flushing will be carried out immediately, followed by retesting to confirm safety and compliance.
Yes. We supply full maintenance records, sampling results, and inspection reports suitable for presentation to auditors, regulators, or insurance providers.

News & insights

News / November 1, 2025

Introducing Complii: A new chapter in building safety and compliance

For years, navigating the world of building safety and regulatory compliance has felt complicated and fragmented. You might work with one specialist for your fire systems, another for water quality, and yet another for electrical testing. It's a system that creates administrative waste, unnecessary risk, and makes it hard to get a complete, clear picture of your building's health.

Insights / September 23, 2025

The benefits of thermographic imaging

Thermographic imaging is a powerful tool for identifying potential electrical faults before they become serious problems. By using specialist thermal cameras, engineers can detect heat patterns that indicate issues such as overloading, loose connections, or failing components.

For businesses, this proactive approach helps reduce risks, avoid costly downtime, and demonstrate compliance with electrical safety regulations.

News / September 23, 2025

PH Water and Air Technologies joins Complii

We are pleased to announce that PH Water and Air Technologies has joined Complii. This addition strengthens our water and air compliance services and further supports our mission to provide trusted, integrated compliance solutions across the built environment.

See all news and insights

Compliance with confidence.

Get in touch for a tailored quotation that fits your site’s needs.