The Chartered Institute of Plumbing & Heating Engineering (CIPHE) is frequently asked for guidance in respect of domestic heating and water supply systems should a property become flooded. Here, we list some of the key questions and answers.

Remember, this advice is for responding if your property is already flooded. If you are aware in advance of a potential flood, there are key actions you should take:

  • Prepare a personal flood plan.
  • Apply measures such as sandbags to minimise flood water entering your property.
  • Remove any important documents and store safely.
  • Turn off your water, electricity and gas supplies.
  • Fill up any spare bottles, pots, pans and the bath (presuming it is away from any floodwater on an upper floor) with cold tap water prior to turning the water off.
  • Move furniture, electrical and sentimental items upstairs.

If you are in the position where floodwater has already entered your property, evacuate and stay somewhere else, keeping yourself and other inhabitants safe.

If this is not possible, or if you are returning to a flooded property the following advice should help.

CIPHE Top Flooding Tips

  • Always turn off your taps and water outlets if you have no water supply.
  • This will prevent the possible backflow of contaminated flood water into your plumbing system.
  • Will also help prevent further problems with overflowing water when the water is turned on again.

If your home is flooded the electricity to the property should be isolated immediately, this would turn off the boiler. Once any flooding has subsided, the complete electrical installation should be checked by a competent electrician, and the boiler isolated until it is checked by a Gas Safe/ OFTEC / HETAS registered service engineer.

If the boiler has come into contact with floodwater it must be checked by a Gas Safe / OFTEC / HETAS registered service engineer. If any electrical components within the boiler have been submerged, they will probably need replacing. Any insulation for the combustion chamber should be checked and replaced if damaged.

No, as long as the heating system has no leaks and system pressure is around 1 bar (sealed systems only), the boiler should work normally. However, if when reconnected the mains water is very dirty, the boiler’s built-in filter may require cleaning by a service engineer. The chances of dirty water reaching your boiler can be reduced by running the first cold water tap in the property (usually in the kitchen), until it runs clear.

Any septic tanks or non-mains drainage systems will need to be checked by a qualified plumbing engineer to ensure they have not been damaged.

We recommend that your plumbing system is flushed out to eradicate any debris and possible contaminants. If you are concerned that there has been further contamination of your system, those competent to do so should disinfect the system. If, after flushing, you still have concerns regarding the colour of the water coming out of the tap (for instance, it is a milky colour) this is probably due to turbulence in the water mains causing aeration of the water. Leave the water to settle in a glass, and it should clear after few seconds.

We recommend that you always boil any open stored water prior to consumption. Preferable is storing water in a clean sterile container with a close-fitting lid (not airtight but excludes light) and is made from a material that will not contaminate the water itself. It could last for several days if kept cool.

It may be worth considering conserving any stored water and flush WCs by utilising the floodwater or rainwater, using a suitable container. If handling floodwater, always use waterproof gloves - water will be contaminated, meaning contact with any cuts or grazes can put you at considerable risk. Keep any stored floodwater out of reach of children.

If you have any concerns over the quality of the water coming from the mains you should not use a dishwasher.

Environment Agency Flood Plan

Be prepared for a flood and respond appropriately if one should occur.

Personal flood plan

Verify a CIPHE member

Members of the CIPHE abide by a code of professional standards, and includes GasSafe/ OFTEC/ HETAS registered operatives. Ask for CIPHE membership and verify online.

Verify a member

Find a plumber/ heating engineer

Need a professional plumber or heating engineer? Search by specialism and location online at the find a plumber directory.

Find a Plumber