Chemical Cleaning & Disinfections

HydroChem Group deliver a turnkey service for meeting and achieving the standards in chemical cleaning and disinfection. HydroChem engineers are experienced and trained for carrying out work on all types of water systems.

Experience gained in and around sites both in the UK and abroad predominantly in the Middle East from large Industrial complexes, Refineries, Military (Army, Air Force and Navy), Governmental facilities, Hospitals, Medical Centres, Multi-rise Commercial Buildings. Universities, Colleges, Hotels, Holiday Camps and Municipal Housing.  This provides a delivery of services for all the requirements that may be needed in chemical cleaning, disinfection and remediation of systems making safe the sites plant services and associated equipment.

This work from the Inspection for Pre-Commission cleaning during maintenance and handover stages of new build or refurbishment of sites.  Post Commission ( On Line ) or remedial cleaning when a system has or is experiencing operational problems and to bring back to full efficiency these systems assist in saving costs, also in the modifications to plant and related equipment.

Disinfection ensures water systems are safe, hygienic and free from microbiological and bacterial contamination which risks health.

HydroChem has dedicated teams of engineers, technicians and chemists trained to inspect, diagnose and give site specific method statements with full recommendations and procedures for its chemical cleaning and disinfection services

Our laboratory and on site testing is used extensively to carry out analysis and microbiological tests to give added support to on-site procedures and aid the engineers in completing the many varied operations undertaken, and give support to the client in the completion of the projects involved.

If required samples may be taken and sent to an independent UKAS laboratory for BSRIA verification and confirmation. However the range of analysis and services from the HydroChem laboratory would meet requirements and save costs if approved by the client.

HydroChem Group are registered to ISO 9001 and ISO 14001 and is a certified member and registered to several organisations, notably Safe Contractor, Construction Line, ( CSCA ) Closed System Control Association, ( BSRIA ) Building Services Research and Information Association and ( LCA ) The Legionella Control Association amongst others.

Chemical Cleaning of Water Systems 

BG 29/2021
BG 50/2013
BG 8552/2012

Pre-Commission and Post Commission ( On-Line ) cleaning of buildings and systems usually  involve closed heating and cooling circuits amongst others being inspected on site, assessed by looking at drawings to write up RAMS ( Risk Assessment Method Statements ) before work commences.

Water samples usually are taken for analysis for suitability for use in flushing, recirculating during the clean and final fill. Metals in the systems are confirmed checked for chemical compatibility for the process to safely commence.

System design and operational parameters which could include sectional cleaning within circuits discussed and confirmed for the recirculating and flushing management which would be addressed in the RAMS for approval along with ( COSHH ) Control of Substances Hazardous to Health. This ensures that the correct protocol and relevant methods for industry standards are employed.

( BSRIA ) Building Services Research & Information Association guidelines in their BG29/2021 are followed along with the ( CSCA ) Closed System Control Association who partner this work in methods for the Cleaning of Pipework.

A typical protocol for carrying out a system clean would typically entail but not be restricted to :-

  • Checking the incoming water quality ( before an initial fill ) advise the use of an inhibitor to arrest corrosion taking place during filling and pressure testing in advance of problems with standing untreated water and the clean commencing.
  • Inspecting the proposed filling/flushing connections and sample the fill water for microbiological contamination.
  • Between the filling and the clean take a sample one week before commencement to check for microbiological contamination and dose a biocide if present and an inhibitor if not added previously to prevent further corrosion.
  • On commencement, 1st flushing ( Dynamic ) to assist in the removal of debris and detritius.  Clean strainers, on becoming clear check iron levels. If acceptable add the preferred chemical flushing agent and accepted cleaning product by the proper means of dosing.
  • Recirculate, check flows and condition of the water ( use sample draw off points such as DOC,valves etc during this time ) Check iron levels.
  • Once complete and accepted by inspection, flush out with water, check strainers for blockage and contents for any foreign contaminants.
  • Check visual quality of water along with the parameters such as iron, TDS etc. Once acceptable and meets requirements dose as soon as practicable with the chosen inhibitor and biocide.
  • Recirculate for a period of time and ensure the levels of inhibitor are correct, re check strainers.
  • Seven days after dosing of corrosion inhibitors and biocide return and take samples in accordance with BS 8552. A certificate may be issued. Return after one month to re sample ensure that the system is dosed correctly and in specification


Hydrochem can carry out in house the BSRIA analysis suite in its own laboratory along with microbiological enumeration or if requires sent to an accredited UKAS laboratory.

Once accepted by the client and operational service contract visits could be arranged with regular analysis carried out to ensure the quality of the water in the system meets specification for its day to day use.

Water quality could suffer and any resultant deterioration by corrosion, scale with associated sedimental deposition and microbiological problems giving rise to biofilm proliferation. This could result in a reduction of efficiency and breakdown of plant it is recommended to sample at least every three months for good practice.


Disinfection of Water Systems 

BS 8558
Guide to the design, installation, testing and maintenance of services supplying water for domestic use within buildings and their curtilages

The control of Legionella Bacteria in Water Systems

HSG 274 part1
The control of Legionella Bacteria in Evaporative Cooling Systems

HSG 274 part 2
The control of Legionella Bacteria in Hot & Cold Water Systems

HSG 274 part 3
The Control of Legionella Bacteria in Other risk Systems

BS 8580
Risk Assessments for Legionella Control

PD 855468
Guide to Flushing and Disinfection of Services supplying water for Domestic use within Buildings and their curtilages

HydroChem provides a full disinfection service for all water systems. Used in conjunction with our Safe-Water programme, it offers support for building disinfections with mains water ( municipal ) and private premises water supply ( Hot and Cold services ), Cold Water Storage Tanks ( CWST ), Associated pipework, Calorifiers and Hot Water Boilers.

Industrial, Commercial and Domestic systems are disinfected by trained and proficient experienced engineers assisted by our chemists and laboratory.

HydroChem use different types of chemical disinfectants with the most suitable employed for the systems which requires it. These vary from standard Chlorine based chemical products to the Eco-friendly Stabilised Hydrogen Peroxide formulations and specific biocides for complex industrial site disinfections.

All completed work would be followed up with a certificate of disinfection for records.





Contact us

To learn more about our services and products, or to get advice or more details, just get in touch. 

The full range of HydroChem Services:

Water Treatment - Industrial

We are leading supplier of Legionella compliance services, water hygiene risk assessment, water treatment, installations and maintenance.

Water Treatment - Domestic

Assessing systems that may pose a risk to exposure to legionella, including humidifiers, air washers, emergency showers and indoor ornamental fountains.

Risk assessment

Ensuring all commercial premises have a statutory duty to control the risk of legionella bacteria in water systems. 

Water Hygiene

Protecting the public from hazards associated with bacteria in water systems particularly Legionella.


We offer an extensive range of water treatment chemicals to suit all processes and requirements.

Chemical Cleaning & Disinfections

We have dedicated teams of experienced engineers to diagnose and give site specific recommendations.

Plant & Equipment

We offer a vast range to ensure that processes are effectively operated to their maximum advantage and costs.


After a Legionella risk assessment, it is likely that corrective or improvement works are required to bring your system up to compliance.

Mould, Air & Surface Remediation

Our protocols allow a building or site be kept clean, environmentally sound and free of contamination.

Borehole Water Treatment

We offer an extensive range of borehole water treatment options to suit all processes and requirements.