Sewage Flooding Guidance

Does sewage flooding pose a health risk?

Sewage largely consists of water and domestic waste from bathrooms and kitchens. During wet weather it is likely to be highly diluted by rainwater. 

Providing that you adopt normal basic hygiene precautions and follow the instructions on this page, you are unlikely to be at any increased health risk.

Basic hygiene precautions should include:

  • washing hands after exposure
  • decontaminating footwear by washing and treating with a mild disinfectant
  • keeping children and pets out of the contaminated area.

However, in the unlikely event of you feeling unwell, we recommend you visit your GP as a precautionary measure and explain that your property has recently been flooded.

Property Flooding

How will the contamination to my house be cleaned up?

Where appropriate, representatives from your sewerage company will assist by cleaning your property. Typically, this could consist of:

  • Removing excess liquid (pumping/sweeping, as appropriate)
  • Removing any sewage debris/faecal contamination
  • Leaving the contaminated areas to dry
  • Applying a mild disinfectant.

WRc tests have established that by using the above approach, disinfection should remove all traces of bacteria within 24 to 48 hours.

If items have been damaged and need further cleansing or replacement, we recommend you first contact your insurance company, and take advice from them. (Some insurers may require photographic or other evidence before damaged items are removed.)

Will the electricity circuits be safe?

If any electricity circuit or equipment has been immersed you will need to ensure that the system is safe before using any appliances or equipment. This safety inspection is best undertaken by a qualified electrician.

What precautions do I need to take to prevent further contamination in my house?

The following simple rules should be followed:

  • Do not wipe over the disinfected areas as this will reduce the effectiveness of the disinfectant
  • Where possible, windows should be opened to remove disinfectant odours
  • Do not turn your heating up to dry the property during the first 48 hours as higher room temperatures may prolong the life of the bacteria.
    What happens next if my house has been flooded?

    If you need to enter affected rooms in the 48 hours following the initial clean up, you are advised to adopt normal basic hygiene precautions such as not touching your mouth and washing your hands after visiting.

    After 48 hours the bacteria in your home should have reverted to the normal background levels found elsewhere in houses unaffected by flooding.

    External/Garden Flooding

    How will the contamination to my garden be cleaned up?

    Representatives from your sewerage company will carry out a clean up. Excess liquid will be removed. This will be followed by a clean up of solids and debris.

    Lawns/borders: It is not normal practice to apply disinfectant to gardens, as this can kill plants and do more harm than good. However, if you feel this would give you extra reassurance then a very mild disinfectant can be applied.

    Laboratory testing has shown the best treatment is to allow nature to take its course. As most contaminants will be at or near the surface, this will produce the maximum exposure to the sunlight’s ultra violet (UV) radiation which is very effective in killing bacteria. If the ground is particularly waterlogged your sewerage company may decide to leave the clean up for a day or two to avoid disturbing the ground and spreading the contamination.

    Hard Surfaces: Hard surfaces such as paths and drives will be cleaned and disinfected. We suggest you keep off these areas for 3 hours to give the disinfectant time to take effect.

    What precautions do I need to take to prevent further contamination of my garden?

    It is important that you do not attempt to dig or rake the affected area. This will spread the contamination further into the soil or turf, where lack of sunlight and the damp conditions will enhance the life of the bacteria

    Similarly you should not attempt to hose the garden down, as this will saturate the ground and prolong the life of the bacteria.

    What happens next if my garden has been flooded?

    The bacterial contamination will die off naturally during the days following the flooding. After an appropriate quarantine period your garden should be safe to resume normal activities. (Factors which influence bacteria decay periods include climatic conditions such as temperature and moisture, vegetation and soil type.)

    Independent laboratory tests carried out by WRc show that bacteria should, typically, reduce to background levels during the following periods:

    • Warm, dry summer conditions: 9 days
    • Damper, cooler, spring/autumnal conditions: 12 days for spills onto turf and heavy (clay) soils; and 26 days for spills onto loose soil and sand
    • Wet, cold winter conditions: 25 days.