Public sewers are designed to protect properties from the risk of flooding in normal wet weather conditions. However, with extreme weather conditions there will always be a flooding risk and unfortunately there are occasions when sewer flooding does occur.
We understand the distress and inconvenience this may cause, particularly when sewage enters your home. We aim to deal with problems relating to flooding promptly and to assist as much as possible afterwards.
Flooding from sewers can occur for other reasons as well, including blockages. If a drain or sewer is blocked and wastewater is still being discharged into it, serious flooding can occur, as the water will build up and escape through manhole covers.
Advice for Customers who have suffered internal property flooding:
Does sewage flooding pose a health risk?
Sewage largely consists of water and domestic waste from bathrooms and kitchens. During wet weather is likely to be highly diluted by rainwater. Providing that you adopt normal basic hygiene precautions and follow the instructions in this leaflet, 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.
How will the contamination to my house be cleaned up?
Where appropriate Northern Ireland Water representatives will carry out an initial decontamination. Typically, this could consist of:
- Removing excess liquid (pumping / sweeping, as appropriate)
- A thorough clean up to remove any debris of faecal contamination
- Leaving the contaminated areas to dry
- Applying a mild disinfectant
The WRc tests have established that by using the above approach disinfection should remove all traces of bacteria within 24 to 48 hours.
We recommend you first contact your insurance company if items have been damaged and need further cleansing or replacement and take advice from them.
For example 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, a qualified electrician will need to check the safety of the system and appliances.
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 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, washing your hands afterwards, etc.
After this time the bacteria in your home will have reverted to the normal background levels to be found elsewhere in houses unaffected by flooding.
Advice for Customers who have suffered external/garden flooding
How will the contamination to my garden be cleaned up?
Representatives of Northern Ireland Water will carry out a clean up. Excess liquid will be removed. This will be followed by a litter pick 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 long term treatment is to allow nature to take its course. As most contaminants will be at or near the surface, this will produce ultra violet (UV) radiation which is very effective in killing bacteria.
If the ground is particularly waterlogged Northern Ireland Water may decide to leave the clean up for a day or two to avoid disturbing the ground and spreading the contamination.
Hard surfaces such as paths and drives will be cleaned and disinfected. We suggest you keep off these areas for three 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 include climatic conditions such as temperature and moisture, vegetation, soil type, etc. Independent laboratory tests carried out by WRc show that bacteria should reduce to background levels in typically the following periods:
- 9 days during warm dry summer conditions
- 20 days during damper, cooler spring / autumnal conditions
- 25 days during wet, cold winter conditions
After this period has expired the bacteria in your garden should have reverted to the normal levels to be found elsewhere in neighbouring gardens.
You can contact the Flooding Incident Line on 0300 2000 100
Text phone for customers with hearing difficulties 03457 023206
If you have any further concerns?
If after reading this advice and you have any further concern please contact the Flooding Incident Line on 0300 2000 100.