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water tanks cleaning disinfection services

Water Tank Cleaning ACoP L8 disinfection services

Cold water storage tank cleaning and disinfection services are core business for Dantek.

Keeping water tanks clean, will prevent sludging, sediment and scale, all of which provide favourable conditions in which Legionella bacteria can grow. Removing scale and biofilm is also important as bacteria can be hidden within a biofilm-forming a barrier to disinfectants. 

The annual inspection of cold water storage tanks will determine if cleaning and disinfection is required, as stated in part 2 of the HSG274.

Our cleaning and disinfection services are carried out by our in-house fully trained engineers, who follow specific method statements and procedure to ensure the work complies with the latest HSG274 and ACoPL8 including COSHH regulations.

Our engineers receive specific technical training and are assessed on their practical and academic knowledge, in order to competently carry out this specialist cleaning work.

We can either use chlorine or a product called Sanosil which is designed to be used in potable water. It also reduces the volume of water needed to flush through the system as it can be left to degrade naturally.

For an instant quote for cold water tank cleaning and disinfection services, please call our sales team today on 01454 417920.

A full method statement and COSHH sheets are provided before work commences.

Cold water tank cleaning and disinfection services are a core business for Dantek. We have been carrying out this type of work for over 17 years and have amassed a wealth of experience on which we are able to draw when tackling a wide variety of challenging jobs for our many clients in the United Kingdom. Our services cover all types of tank from routine domestic sizes all the way up to very large and complex commercial systems. Whether we are working on a small residential system or a large industrial one, we always take measures to ensure that any disruption to our clients is kept to an absolute minimum and we endeavour to carry out the work at a time that is convenient for all concerned.

Water tank cleaning procedure


A water tank clean must be carried out by trained technicians with the correct PPE and equipment following a method statement and keeping a detailed procedure log of the work as it takes place.

A risk assessment prior to the work will identify any hazards associated with the tasks and how to reduce or control any risks identified.

The first thing to do is to inform all building occupants of the cleaning and disinfection work taking place and to put out warning signs on all outlets to stop building users turning on taps/showers during the work.

The tank inlet must be isolated, so the tank can be drained and inspected. If safe to do so technicians enter the tank and manually remove all debris, scale and sludge with a wet vac, and then refill tanks with fresh mains water.

The inlets and outlets of storage vessels are isolated before the disinfectant is dosed. The tank is pre-dosed with chlorine to achieve 50PPM free residual chlorine in the tank.  Chlorine is added at 0.5 litres per m³ and mixed in the tank.

Once the required level of chlorine is achieved and maintained the outlet of the tank is opened to allow the chlorinated water to flow around the system.

The chlorinated water flows to all outlets and checked by a technician by successively opening the outlets in the system e.g. all taps and showers.

The free residual chlorine level in the tank is regularly checked and topped-up if the dose of chlorine falls below 50PPM in the tank and at the outlets.

Ensure 50PPM is achieved at all outlets for one hour or 2 hours at 20PPM.

For vessels over 5m³ neutralisation of chlorine requires 6.9g per m³ sodium thiosulphate for every PPM of chlorine. If total cistern volume exceeds 5 m³ the chlorine solution must be neutralised and emptied to a foul drain. The neutralised solution must not be allowed to pass through to the outlets.

Test chlorine content of the incoming main. Re-instate tank and flush the system until all outlets achieve <0.5PPM free chlorine or no greater than the incoming main.

Ensure all warning labels are removed.

Leave site clean and tidy, and put system back in service.

Complete report on completion of work, including the current condition of tank and any remedial actions required.


For the tank clean and disinfection work to take place the site must be able to provide a foul drain within a reasonable distance from the tank, capable of receiving the appropriate amount of stored water on site, e.g. WC.

Power will be needed for the wet vac, pumps and site lights so must be available near the area of work. It really helps if there is a staff member or their agent who is familiar with water systems is on-site for the duration of the works. Access will be needed to all areas of the system including normally locked areas such as cleaners’ cupboards. Finally, there must be an adequate supply of fresh town mains, so the tank and system can be put back into normal working order after the cleaning and disinfection work has taken place.


HSE & COSHH Compliant Services

All of the services that we provide are carried out by our in-house team of fully trained, fully qualified and highly experienced engineers. Every member of our team follows the specific method statements for each project on which they work, as well as the standard procedures that we have in place. These statements and procedures are designed to ensure that all work complies with the latest HSG274 technical guidance and ACoPL8 code of practice issued by the Health and Safety Executive, as well as all relevant COSHH regulations.

Our engineers receive specific technical training and are subject to a thorough and continual assessment process, which covers both their practical skills and academic knowledge, to make sure that they are able to carry out this specialist cleaning work safely and efficiently at all times.

We want you to be absolutely sure that when you work with Dantek, you are dealing with consummate professionals who know exactly what they are doing. Our clients have very high standards and we are only able to meet and exceed these standards because we adhere to strict codes of practice on every project that we undertake.

Call today for an instant quote that covers everything that will need to be done in order to ensure that your system is clean and safe, please call our sales team today. We will, of course, conduct a site survey to ensure that our quotation is accurate and, should you wish to proceed, we will provide you with a full method statement and COSHH sheets before work commences.