Southern Water is investigating after a mystery ‘fatberg’ measuring 2ft by 3ft washed up on Goring beach this week.
Specialist teams are now carrying out tests on the mass of waste at its lab in Falmer after it was found on the beach at the end of Sea Lane on Monday.
Stephen Edwards, who works in Network Protection and Enforcement at Southern Water, said: “It took two people to lift this mystery ‘fatberg’, which is made up of different fats.
“It would be impossible to pinpoint exactly where this has come from - it could even be ship waste that has floated ashore - but hopefully we’ll be able to determine more following further tests.
“It does serve as a timely reminder ahead of Christmas, that flushing the wrong things down sinks and loos can create nasty consequences.
“An unsightly mass of waste on the beach would be the least of anyone’s problems, as blockages in the sewer can cause homes to flood with wastewater.”
Southern Water’s own Unflushables and Fat, Oil and Grease team carry out vast amounts of work to help stop unflushable items being flushed into the sewer, such as wet wipes and sanitary towels, a spokesman said.
This includes working with businesses and traders.
From January to March this year, Southern Water invested half-a-million pounds to jet-clean Worthing’s sewers.
More than 200 tonnes of debris, including wet wipes, fats, oils and other materials were found.