Seal of Dane County County of Dane
Dane County Sheriff's Office

Ice Ordinance Information

Dane County Ordinance Chapter 71 requires certain motorized vehicles operated on lakes within Dane County to be equipped with flotation. This page highlights some of the requirements. 

Click here to view the full ordinance.

Effective June of 2020, flotation inspections and certificates are no longer required to operate a vehicle on the icebound waters of Dane County lakes.  Dane County Ordinance 71.11 was amended and no longer requires them.

  • You must still maintain flotation devices on vehicles less than 850 pounds on the icebound waters of Lakes Mendota, Monona, and Wingra. Flotation devices are also required on vehicles between 750 and 850 pounds operating on any other icebound lake waters. 
  • A special certificate is available and required for vehicles weighing 850 pounds or more. Please see Ordinance 71.13 for these exceptions to the weight limitations. 
  • Failure to have the flotation devices or to obtain a special certificate for the weight exception will likely result in a citation.


Flotation must be mounted as equally as possible, front and back, or side to side. The floats must be hard-mounted to the machine (bolts, metal brackets, chain, cable, etc.). Nylon straps, bungee cords, ropes, etc. are not permitted.

The flotation material used most commonly is styrofoam, either in sheets, blocks, or sprayed. Popcorn or peanut type packing material is not acceptable. The flotation should be enclosed/protected by wood, metal, aluminum, or plastic to prevent it from breaking. Air-filled containers are not acceptable. The Nebulus Emergency Flotation Device and the pre-made foam filled nylon cases are examples of approved flotation systems. Pictures of some sample flotation are shown below.

atv nebulus frontatv nebulus backatv caseatv case 2ATV picATV 2ATV with FlotationSnowmobile with flotation

Each cubic foot of flotation will float 60 lbs. Diameter measurements can be deceiving. Each diameter measurement listed below equals one cubic foot of flotation. If using cylinders, you will need to multiply the length times 5 for an ATV and times 16 for a snowmobile to get the correct length of cylinder needed.

  • 6-inch cylinder x 61 inches long
  • 8-inch cylinder x 35 inches long
  • 9-inch cylinder x 27 inches long
  • 10-inch cylinder x 22 inches long
  • 12-inch cylinder x 15 inches long
  • 14-inch cylinder x 13 inches long

Flotation Requirements

Lake Mendota – Lake Monona – Lake Wingra

All vehicles under the 850 lbs. maximum weight limit require flotation. 

All Other Dane County Lakes

Vehicles weighing under 750 lbs. have no restrictions and therefore do NOT require flotation.

Vehicles weighing between 750-850 lbs. require flotation.

Vehicles weighing over 850 lbs. require a permit.

Specific Vehicle Type Flotation Information

Snowmobiles: Require 16 cubic feet of flotation.

All-Terrain Vehicles (ATVs): Require 5 cubic feet of flotation. Note: ATVs are designed to float themselves, but not the passenger(s) and gear.