Water & sample testing.

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What is water sampling and testing?

Water sampling and testing is the process of analysing water systems for microbial and chemical contaminants to confirm safety, quality, and compliance with UK regulations. It’s an essential part of maintaining healthy water systems and forms a key element of every water safety plan.

At Complii, we provide accredited water sampling and testing services in line with ACoP L8, HSG274, and BS 7592:2008, ensuring reliable results and clear interpretation. All samples are analysed by UKAS-accredited laboratories, and our reports provide practical, prioritised actions that help you maintain control of your water systems. Whether for Legionella monitoring, drinking water quality checks, or system validation, we deliver trusted results that keep your business safe and compliant.

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 water and sample testing.

Full compliance assurance

Our sampling and testing programmes are conducted in accordance with ACoP L8, HSG274, HTM 04-01, and BS 7592:2008, meeting the strict requirements of the HSE, DWI, and Environment Agency.

Reliable results from UKAS-accredited laboratories

Every sample is processed in a certified UKAS laboratory, giving you confidence in the accuracy, traceability, and regulatory validity of all test results.

Early detection of waterborne bacteria

Routine sampling identifies Legionella, Pseudomonas, coliforms, and other bacteria early, helping to prevent outbreaks and safeguard building users.

Comprehensive testing scope

We offer full microbiological and chemical testing suites, including Legionella, Pseudomonas, E. coli, total viable counts (TVC), pH, metals, and general water chemistry.

Clear, action-focused reporting

You receive simplified, easy-to-read reports with professional analysis and recommendations, enabling fast, informed decisions to maintain compliance and water quality.

Ongoing support and monitoring integration

Our team integrates sampling into your water hygiene programme, helping you track trends, verify control measures, and plan preventative maintenance.

Your questions answered.

Frequency depends on system type and risk level. As a general guide, Legionella sampling should be performed at least annually, or more frequently in high-risk settings such as healthcare, education, and hospitality.
Sampling applies to hot and cold water systems, cooling towers, closed systems, and domestic supplies. It may also be required for new installations or following any loss of control within your water hygiene regime.
We test for Legionella, Pseudomonas, total viable counts (TVC), coliforms, E. coli, pH, metals, and full chemical profiles, ensuring all aspects of water safety are covered.
All sampling and analysis are carried out in accordance with BS 7592:2008, ACoP L8, HSG274, and, where applicable, HTM 04-01 for healthcare settings.
Yes. Our experts provide a detailed explanation of the findings and clear, prioritised actions to resolve any non-conformities or quality issues identified.
Absolutely. We can arrange fast mobilisation for reactive sampling in the event of suspected contamination or following a system failure, with rapid turnaround of results.

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.

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