Treatment and maintenance of private water supplies

Tips on how to treat and maintain your water supply, cleaning holding tanks, protecting your supply in winter and replacing pipes and fittings.

You can treat and maintain your water system yourself. If you think there is any risk of causing harm to yourself, or others, you should look for help from a supplier of water treatment equipment and servicing.


Deciding on the most appropriate type of treatment for your supply is best left to an expert. At an absolute minimum, some form of disinfection will be needed to kill any bugs in the water.

If there are particles in the water you'll need at least one filtration stage to remove them, treatment may be needed too.

You might need other treatment systems, like media filters and pH correction to ensure the water complies with regulatory standards.

Maintaining your treatment system

You must make sure that your private water supply is maintained. Regular maintenance will reduce the risk of contamination and ensure your water is as safe as possible. 

Every aspect of your supply must be protected and reviewed regularly. Make sure:

  • the source is protected, for example fencing around a spring is in good condition
  • contamination, including faecal matter from grazing animals, pesticides, fuel spills or septic tank waste is limited
  • storage tanks are inspected regularly to ensure there's no contamination
  • storage tanks have lockable lids to make sure no unauthorised access is possible
  • debris is cleaned out and tanks disinfected regularly

Any treatment installed will need to be maintained, so it will be an ongoing expense. It’s important to regularly:

  • check the treatment system is performing correctly
  • carry out regular maintenance
  • record routine maintenance tasks and faults

If you can't do this yourself, it may be worth taking out a service contract with a reputable supplier who can keep your treatment system working to specification.

If you share your private supply with other properties, it is often more affordable to install a central treatment facility.

You need to know what to do if your private water supply runs out.

More advice on managing you private water supply

Cleaning holding tanks

Over time, particles of dirt and minerals known as sediment will build up at the bottom of your tank. This might make your water dirty, or allow bacteria to grow in it.

To clean your tank, open it and drain out any remaining water. Remove the sediment that has built up by scrubbing or pressure-washing the inside walls of the tank. You may wish to flush the system with chemical disinfectant when refilled and run this to waste. A chemical clean will reduce the risk of recontamination from opening the tanks to the environment.

You should dispose of the waste water, especially if it contains chemicals, in a way that doesn't damage the environment or contaminate other waterways and habitats nearby.

These are generic instructions. If you are not sure how to do this, contact a water engineer. You may wish to include this in any maintenance contracts you have.

Protecting freezing pipes and tanks in winter

Very cold temperatures can cause water in supply pipes to freeze. When water freezes it expands which can cause pipes to crack. You can cover your pipes with an insulating sleeve, or lay them underground. Pipes laid underground are less likely to be damaged and will be better insulated. Burying to a minimum depth of 30cm is recommended.

Where possible don't expose pipes and tanks to sunlight or heat sources. Keeping water as cold as possible will promote microbiological die off and reduce the risk of bacterial growth.

Pipes and tanks exposed to weather will deteriorate quicker. To make the most of your investment, you should partially bury tanks and/or apply weather protective treatments.

Replacing pipes and fittings

Not all materials are suitable to be in contact with water as part of a water supply. Certain materials are able to leach into the water and compromise water quality for example lead, some solders, some plastics.

To make sure water remains safe, look for the WRAS Approved Product logo. This ensures the material is suitable for applications in contact with drinking water.