Neglecting your water tank can lead to the build-up of sludge and scale which creates the perfect environment for the accelerated growth of biofilm and water-borne bacteria like Legionella. Leaving your water untreated and allowing its hygiene to deteriorate is extremely harmful for users as it can lead to conditions like Legionnaire’s disease.
To protect against this and to ensure your water supply remains safe for purpose, regular cleaning and disinfection of your hot and cold water tanks is recommended.
If the water in your storage tank becomes stagnant, this will encourage the rapid growth of harmful bacteria and scale.
Stagnation is not only caused by the water supply being out of use. It can also occur if the tank you are using is too large for your needs or if there are areas in your system that are causing blockages or the water to flow slowly.
To reduce this risk, you should assess your pipework and ensure to remove or replace any parts of the system that may cause low flow areas. An example of this would be dead legs or dead ends.
Any parts that are not used frequently such as showers and taps in additional bathrooms should also be flushed weekly to avoid any trapped water becoming stagnant.
Even with these measures, some degree of water stagnation is inevitable which is why we recommend regular water tank cleaning and disinfection.
The regularity with which your water tank will need cleaning will depend on whether the water is potable or not. Cold water tanks for potable water will need cleaning more frequently as you need to ensure the water remains safe for human consumption.
With this in mind, internal inspections and water sampling should be carried out every 6 months on potable water tanks to check for any bacteria breakouts, and every 12 months on non-potable water tanks.
The tanks should be fully cleaned and disinfected annually, or more frequently if any contamination is found within the supply. When cleaning your water tank it is important to make sure you are adhering to the L8 guidelines created by the Health and Safety Executive.
Before starting the cleaning process, the tank will need to be isolated from the water system so that it can be drained.
The level of cleaning required will vary depending on the condition of the water tank,. For those in good condition, this may just involve hosing out any debris. If over time there has been a significant build-up of algae and scale, brushes or scouring pads may be necessary to remove any staining.
Once the tank has been cleaned, it can be refilled with fresh water from the system.
This is where the disinfection begins. By checking the pH of the fresh water, you can then chlorinate the supply to ensure it has the appropriate concentration (ppm) for the volume of the tank. With this achieved, the outlet can be reopened to allow the freshly disinfected water to flow through the system.