Periods of prolonged and intense rainfall across parts of southern England have this year seen river levels rise and put drainage systems under pressure.
In many areas, the same underground pipes carry both household wastewater and rainwater from roads, roofs and drains.
Water companies say that when heavy or sustained rain fills these systems beyond capacity, sewage can be forced back up through manholes, drains or household pipework – a process described as “hydraulic overload”.
Further strain can be caused by groundwater seeping into pipes through cracks or inspection chambers during wet weather.
In Stanford Dingley, in Berkshire, raw sewage emerged from manholes and flowed into gardens during a period of particularly heavy rainfall.
Homeowner James Devine said: “We get lots of sewage, lots of toilet paper and other bits and pieces coming into our garden.”
In Wimborne Minster, in Dorset, Susannah Gill described waking to find her garden underwater after severe weather in January.
She said it was “amazing” to find what people put in their sewers – including wipes and earbuds – and called the scene “pretty revolting”.