How to keep your tank clean and vermin free


While new homes will have newer central heating systems, many older properties still rely on a cold water storage tank system. This will supply water to bathrooms and in some cases even be the main drinking water supply in a home. If this is you, then read on for our tips on good maintenance of your tank to ensure a clean supply of cold water, free from vermin and other impurities.

What are the characteristics of good water quality?

If your water is supplied from a cold water tank, you want it to:

  • Be clear and odourless
  • Have a very low microbial population
  • Be at around 20 degrees Celsius

What you don’t want to see on your tank or in your water are:

  • Any visible sediment on the bottom of the tank
  • Any film deposits on the tank or surface of the water
  • Any scummy deposits along the top of the waterline
  • Indications of corrosion to the metalwork
  • Signs of mould on the tank or even in the water
  • Higher water temperatures – anything above 20 degrees Celsius

How to ensure your tank is clean and secure

For a tank that provides safe, clean water, free from impurities look out for the following:

  • A tank with a capacity of around 250 litres. This way you can be assured that it is replenished with fresh water frequently and does not have residual or standing water for long periods of time.
  • It is made of a material that is approved. Older tanks are typically made of galvanised iron, but this can rust over time and you could find flecks of rust in the water. Newer tanks are made of polyethylene – a type of plastic – and are specifically designed for the storage of drinking water.
  • It has a tight-fitting lid. This will ensure that insects, dust, birds and vermin can’t find their way in.
  • It has an overflow pipe and vents. Ideally, these should also be fitted with screens to prevent dust and insects from finding their way in.
  • It is well insulated and away from direct sunlight. This will ensure that your water temperature remains constant and as cold as possible.


Regular maintenance of your cold water tank is essential to ensure it remains clean. A visual check will make sure that the lid is secure and that no animals have found their way into your water tank. You can also check for any signs of scale build-up, any deposits on the bottom of the tank, or any signs of degradation of the tank. You also want to keep an eye out for a lower turnover of fresh water or any change in the water temperature.

If you are in a rented property it is the responsibility of your landlord to ensure that regular cleaning and checks are undertaken to control for legionella.

If you would like more advice on cold water storage tanks or would like a professional check, repair or replacement then talk to our Platinum Plumbers experts. Find us on 020 8855 0361 or at and ask us for your free, no-obligation quote.

2023-01-09T08:48:58+00:00 May 30th, 2019|