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Flooding and sewage problems (3)

Septic tanks, private sewage treatment and even mains sewerage may be affected by floods

During the recent heavy rains and subsequent flooding, many septic tanks, small private sewage treatment systems and even mains sewerage will have been adversely affected. For many, this will be a cause of significant anxiety for a number of reasons, not least the inability to flush toilets combined with the contamination of homes and gardens. Most important is the potential for ill health arising from the ‘germs’ in faecal material within the flood water and standing surface water.

Key actions can reduce the risk of becoming unwell

Infection problems arising from floods in this country are rare. Usually any harmful bugs in floodwater become very diluted and present only a low risk, but there are a few precautions to be aware of when dealing with flooding which should prevent unnecessary additional health problems. Set out below are some key actions that will help you or your family reduce the risk of becoming unwell whilst flooded or suffering from contaminated surface run-off.

  • Wherever possible try to avoid coming into direct contact with floodwater. If you have to go into the water, wear waterproof gloves and rubber boots and remember to be careful of potentially concealed hazards.
  • Wash your hands – this is the most important way to get rid of harmful bugs. Use warm, clean water and soap, then rinse and dry your hands after going to the toilet, before eating or preparing food, after being in contact with flood water, sewage or with items that have been in the water. Use cold water to wash if warm is not available. If there is no clean water, use disposable soapy, wet wipes to carefully clean all parts of your hands and dry them.
  • Keep children out of the water
  • Don’t eat any food that has been touched or covered by floodwater or sewage.

Our usual advice is not to empty you septic tank when the ground is flooded or saturated

We do not normally advise you to empty your septic tank during flooding or when the ground conditions are saturated because emptying the tank could cause it to float out of the ground and damage the inlet and outlet pipes. Access to the tank through flooding may also be difficult and the tank is likely to backfill immediately with water, again rendering the WCs in the house unusable. 

Key points once floodwaters have receded

Once floodwaters have receded, there are several things homeowners should remember:

  • Do not use the sewage system until water in the soil absorption field is lower than the water level around the house.
  • Have your septic tank professionally inspected and serviced if you suspect damage. Signs of damage include settling or an inability to accept water. Most septic tanks are not damaged by flooding since they are below ground and completely covered. However, septic tanks and pump chambers can fill with mud and debris, and must be professionally cleaned.
  • Only trained specialists should clean or repair septic tanks because tanks may contain dangerous gases.
  • If sewage has entered your house clean the area and disinfect the floor. Use a bleach solution to disinfect the area thoroughly.
  • Do not compact the soil over the soil absorption field by driving or operating equipment in the area. Saturated soil is especially susceptible to compaction, which can reduce the soil absorption field's ability to treat wastewater and lead to system failure.
  • Examine all electrical connections for damage before restoring electricity.
  • Be sure the septic tank's manhole cover is secure and that inspection ports have not been blocked or damaged.
  • Check the vegetation over your septic tank and soil absorption field. Repair erosion damage and re-seed areas as necessary to provide turf grass cover.
  • Consider if, in the longer term, an alternative sewage disposal system is preferable as recurring floods are unfortunately not unlikely. This may include re-siting the septic tanks and soak-aways onto higher ground via a pump, or connecting to mains drainage where available.

Issues with mains or adopted pumping stations

If your problem relates to backing-up mains drainage or over-flowing adopted pumping stations, then you should immediately contact your water company.

For much of Herefordshire this is Welsh Water on 0800 853968 or in some parts of north and east Herefordshire, Severn Trent Water on 0800 7834444.

For help and advice

Anyone who wishes to report and seek advice on sewage related problems at their property or business can contact Herefordshire Council on 01432 261761 or email

Tags: Public Health, Environment and waste