Farmers and landowners are now being urged to protect themselves against the "blight on the countryside" after figures were released by the Department for the Environment, Food and Rural Affairs (Defra).
According to Defra there were 90,585 incidents across the region in 2020/21 compared to 70,830 during the previous 12 months, an increase of 19,755.
The biggest increase was in Sandwell, where the number of incidents leapt from 5,972 to 10,330.
Elsewhere cases rose from 2,463 to 3,056 in Wolverhampton, 3,441 to 3,618 in Walsall, 1,224 to 1,834 in Dudley and 21,761 to 22,750 in Birmingham.
Fly-tipping offences on agricultural land also increased, year-on-year, from 211 to 240.
While local authorities pay to clean up fly-tipping on public land, on private property it is the responsibility of the landowner.
“Fly-tipping is an unwelcome blight on our countryside and can represent far more than an inconvenience to victims of the crime,” said Rupert Wailes-Fairbairn, of rural insurance broker Lycetts.
“Incidents not only pose significant environmental and human health risks, but also a legal and financial burden for farmers and landowners.”
According to the National Rural Crime Network clean-up bills per incident average around £1,000, but large-scale incidents can cost upwards of £10,000.
Mr Wailes-Fairbairn, said that farm businesses can insure the risk.
“In some cases, farmers can be repeatedly targeted and costs can quickly escalate,” he said.
“Many combined farm policies, however, will cover the clean-up costs, typically capped between £10,000 and £15,000 for the insurance period.”
Mr Wailes-Fairbairn said that environmental criminals often act when it is dark and urged vigilance.
“Prevention is better than cure and steps should be taken to ensure access to land and fields is restricted, where possible, with physical barriers,” he said.
“Gates should be locked when not in use and although witnesses of fly-tipping incidents should not approach the perpetrators, by cutting back hedges and installing exterior lighting, visibility for the landowner can be notably improved.
“The installation of security cameras can also act as a deterrent and help in securing successful prosecutions.”