Tons of bricks, paving blocks, concrete and rubble have been dumped illegally on the banks of the River Welland near Market Harborough.
The major fly tipping incident has scarred the river bank on a site between Market Harborough and Lubenham.
The dumping was discovered last Thursday by a local walker.
The Market Harborough man, who asked not to be named, said: “It looks like two or three lorry loads have been dumped there.
“It’s a real eyesore in a rural area, as well as being potentially dangerous and possibly interfering with the river course.”
The walker said he had reported the incident to Harborough District Council.
The fly-tipping site is on the south bank of the river, about 400 yards from the edge of Lubenham village.
A vehicle would have had to have been driven across a field to reach the tipping site.
Some councillors have been warning of the danger of an increase in fly-tipping, after Leicestershire County Council introduced new charges to accept this sort of waste at recycling sites.
The county council has been badly hit by cuts, and says it has had to make savings and find new revenue sources.
From May 4 this year, Leicestershire’s waste sites began charging £3 per tub (equivalent to a large bucket) to accept hardcore, rubble and soil.
Customers are asked to pay with a debit or credit card.
Unscrupulous builders could seek to maximise their profits from small jobs by avoiding the council tip charges and illegally dumping the waste in a quiet country spot.
“Yes, we have warned about this” said Harborough District council’s Liberal Democrat councillor Phil Knowles.
“I really do hope that this incident is not an indication that we were correct about fly-tipping increasing in the wake of the recent changes.”
Harborough District Council’s Conservative leader Cllr Blake Pain is also the Leicestershire County Councillor responsible for waste management.
He said: “We’re looking to take on the perpetrators of fly-tipping and bring them to justice.
“We know where the fly-tipping hot spots are and we’re going to focus on them, including using CCTV, to catch the people who are blighting our district.”