Farmers and private landowners in Derbyshire are being asked to help drive down incidents of fly-tipping,
The county council and Environment Agency said their monitoring and enforcement had cut illegal dumping in the county by 27% since 2008.
Now letters are being sent to landowners, appealing for help in building a picture of the problem.
Officials said fly-tipping is not only ugly but is dangerous for animals and costs thousands of pounds to clear.
James Beckett from the Environment Agency said: "We are working with Defra, private landowners and other interested parties to identify the scale of the problem of fly tipping on private land and develop solutions.
"Our work with farmers and landowners in Derbyshire will make an important contribution to shaping the outcomes of this research".