image of DEP trailer

Tow vehicles and trailers must be compatible with hitching, braking, and wiring systems. While your vehicle may have certain tow ratings, you must have a matching hitch system that can handle the same specifications. To ensure safety, you may have to install extra towing equipment. 

Safety chains are required for travel trailers. The purpose of safety chains is to prevent the trailer from separating from the tow vehicle in event of hitch failure such as a hitch ball that has loosened. The chains should be crossed in an "X" fashion below the ball mount, with enough slack that they do not restrict turning or allow the coupler to hit the ground.

Breakaway switches are also required for any trailer having a gross weight of 1500 lbs. or more and manufactured after December 31, 1955. They are designed to activate trailer brakes if the tow vehicle becomes separated from the trailer. One end of the breakaway switch is attached to an electrical switch on the trailer frame and the other end is looped around a stationary hitch component on the tow vehicle. If the two vehicles become separated, the cable pulls a pin inside the breakaway switch applying full power from the trailer battery to the trailer brakes.


Trailer Hitch connector and electric brake battery box

Towing Requirements

Truck: 3/4 ton truck or higher  
Hitch: Class 4  
12 foot trailer (Regional Offices, Naushon, Aquinnah): 3,850 GVWR 2" ball, with electric brakes
20 foot trailer :10,000 GVWR 2 5/16" ball, with electric brakes

GVWR: A gross vehicle weight rating (GVWR) is the maximum allowable total weight of a road vehicle or trailer that is loaded, including the weight of the vehicle itself plus fuel, passengers, cargo, and trailer tongue weight.

Before driving, make sure your vehicle and trailer maintenance is current. This is very important because towing puts additional stress on the tow vehicle.

  • Check and correct tire pressure on the tow vehicle and trailer.
  • Make sure the wheel lug nuts/bolts on the tow vehicle and trailer are tightened to the correct torque.
  • Be sure the hitch, coupler, draw bar, and other equipment that connect the trailer and the tow vehicle are properly secured and adjusted.
  • Check that the wiring is properly connected—not touching the road, but loose enough to make turns without disconnecting or damaging the wires.
  • Make sure all running lights, brake lights, turn signals, and hazard lights are working.
  • Verify that the brakes on the tow vehicle and trailer are operating correctly.
  • Check that all items are securely fastened on and in the trailer.
  • Be sure the trailer jack, tongue support, and any attached stabilizers are raised and locked in place.
  • Check load distribution to make sure the tow vehicle and trailer are properly balanced front to back and side to side.
  • Check side and rear-view mirrors to make sure you have good visibility.
  • Make sure you have wheel chocks.


Tow vehicles often have more frequent maintenance requirements, including changes of engine and transmission oils and filters, lubrication of components, and cooling system checks. Check the vehicle manual for information on scheduled maintenance. Here are some additional maintenance suggestions.

Periodic inspection and maintenance of tow vehicle and trailer tires and wheels are essential to towing safety, including spare tires. Proper tire pressure affects vehicle handling and the safety of your tires. You can find the correct tire pressure for your tow vehicle in the owner's manual or on the tire information placard.

    • Underinflation reduces the load-carrying capacity of your tow vehicle or trailer, may cause sway and control problems, and may result in overheating, causing blowouts or other tire failure.
    • Overinflation causes premature tire wear and affects the handling characteristics of the tow vehicle or trailer.

On a regular basis, have the brakes on both vehicles inspected. Be sure that necessary adjustments are made and any damaged or worn parts are replaced.

Check the nuts, bolts, and other fasteners to ensure that the hitch remains secured to the tow vehicle and the coupler remains secured to the trailer. The connection point may require periodic lubrication to permit free movement of the coupler to the hitch ball.

Make sure connector-plug prongs and receptacles, light bulb sockets, wire splices, and ground connections are clean and shielded from moisture. Lightly coat all electrical terminal connections with nonconducting (dielectric), light waterproof grease.

Clean the prongs with very fine sandpaper, being careful not to damage the contact area.

Clean the surface deposits in the connector holes. (Make sure the lights are off to prevent blowing a fuse.) Try to clean off only the deposits and lubricate lightly with dielectric, light waterproof grease.

Annual Inspection

A MassDEP contractor will be conducting an annual maintenance and inspection procedure on all trailers.  The contractor will coordinate with each town prior to the annual inspection to identify repair and resupply requirements.  It is requested that each community inspect the interior and exterior of the oil spill response trailer periodically during the year and to report to MassDEP any damage, vandalism or maintenance issue identified.  See "Reporting and Resupply " link for more info.