Section 2: General Maintenance

The products used to clean, repair and maintain vessels are often harmful to the aquatic environment. Though individual exposures are not catastrophic, cumulative impacts can be damaging. Boaters and staff are important in protecting water quality while performing routine maintenance. This section provides a variety of practices to reduce the environmental impact of these activities.

Learning Objectives

By the end of this section, you should be able to:

  • Identify and endorse engine maintenance practices to reduce potential release of oils and fuels.
  • Prepare staff and boaters to winterize vessels with attention to measures that will benefit the environment and boat owner.
  • Understand the variety of anti-fouling paints available and their tradeoffs.
  • Establish painting operations to reduce waste.
  • Minimize impacts of coating operations (compound waxing, fiberglassing, teak refinishing and varnishing).

Best Management Practices

Repair and Maintain Engines with Care

  • Minimize the environmental impacts of engine repair and maintenance.check box for Regional Best Management Practice
  • Use dry pre-cleaning methods, such as wire brushing. check box for Regional Best Management Practice
  • Avoid unnecessary parts cleaning. check box for Regional Best Management Practice
  • Adopt alternatives to solvent-based parts washers such as bio-remediation systems. These systems use microbes to digest petroleum and are self-contained with no effluent discharge. The cleaning fluid is a mixture of detergent and hot water. Microbes such as hydrocarbon-degrading bacteria are added periodically to digest the accumulated wastes. check box for Regional Best Management Practice
  • Use water-based, non-VOC (volatile organic compound) cleaners that are less hazardous than solvent-based degreasers. They are also less toxic and non-flammable. If you use a solvent to clean engine parts, see Section 3: Handle Solvents Carefullycheck box for Regional Best Management Practice
  • Use drip pans when handling any type of liquid. Use separate drip pans for each fluid to avoid mixing. Recycle the collected fluid. Mixed liquids cannot be recycled and must be stored and disposed of as hazardous waste. check box for Regional Best Management Practice
  • Store engines and engine parts under cover on surfaces such as asphalt or concrete.
  • Do not wash engine parts over the bare ground or water.
  • Use funnels to transfer fluids.
  • Drain all fluids from parts prior to disposal.
  • Clean engine repair areas regularly using dry cleanup methods (e.g., capture petroleum spills with oil absorbent pads).

For information on storing and handling oil and fuel, see the Petroleum Control Unit. For information on disposal of used oil or filters, see the Waste Management and Recycling Unit.

Winterize Safely


There are two types of antifreeze. Antifreeze with ethylene glycol is a greenish-yellow, odorless, sweet-tasting chemical that poses a serious health risk to humans and animals if ingested. Antifreeze with propylene glycol is pinkish and less toxic to humans and animals — and the one recommended for use.

Both types of antifreeze can be toxic to organisms in the water such as fish, bottom-dwelling organisms, and plankton. Used antifreeze may or may not be considered a hazardous waste depending on the levels of certain metals, such as lead, cadmium, or chromium — or if mixed with other substances such as gasoline or solvents. If you generate antifreeze, you must evaluate it to determine if it is a hazardous waste. Additionally, some states do not allow discharge of antifreeze directly into the water (“blow out”) or onto any surface that would drain to the water. See your State Laws page for additional information.

  • Use only propylene glycol antifreeze for all systems. It is substantially less toxic than ethylene glycol antifreeze. check box for Regional Best Management Practice
  • Never use ethylene glycol in potable water systems; it is highly toxic and cannot be reliably purged.
  • Collect and recycle or dispose of antifreeze by approved methods. Do not dispose of antifreeze by pouring it into your septic system, into a dry well, on the ground, or in the trash. Further restrictions may be in place to prohibit discharge to any body of water or to a sanitary sewer or other means that directs the waste liquid to a wastewater treatment plant. Dispose into a sanitary sewer only with permission of the municipal sewer facility. check box for Regional Best Management Practice
  • Use the minimum amount of antifreeze necessary for the job.
  • Do not mix cleaning solvents, degreasers, or waste fuel with used antifreeze, because this can result in a hazardous waste mixture.
  • Train employees on the proper way to handle antifreeze.

Bilge Area

  • Inspect bilges prior to extended boat storage. Encourage boat owners to keep bilges clean and dry during storage season. check box for Regional Best Management Practice
  • Offer bilge cleaning service and encourage patrons to use bilge socks.check box for Regional Best Management Practice
  • Provide educational materials that promote engine and bilge maintenance. check box for Regional Best Management Practice


  • Add stabilizers to fuel to prevent degradation. Stabilizers are available for gasoline and diesel fuels and for crankcase oil. These products protect engines by preventing corrosion and the formation of sludge, gum, and varnish. Also, the problem of disposing of stale fuel in spring is eliminated.
  • Be sure fuel tanks are 85-90 percent full to prevent flammable fumes from accumulating and to minimize the possibility of condensation leading to corrosion.
  • Do not fill the tank more than 90 percent full. The fuel will expands as it warms in the spring; fuel will spill out the vent line of a full inboard tank.
  • Be sure the gas cap seals tightly.
  • Use the highest rated octane recommended by the engine manufacturer. Premium fuels are more stable than regular grade fuels.


In the spring, used shrink-wrap is often discarded and ends up in landfills. Shrink-wrap can be recycled and by doing so, reduces the cost of solid waste disposal for marinas.

  • Promote reusable canvas or recyclable plastic covers. Some manufacturers will clean and store canvas covers during the boating season.
  • Recycle used plastic and shrink-wrap covers. See Waste Management and Recycling Unit for more information.

Boat Cleaning

  • If possible, use or sell cleaning products that are environmentally friendly (e.g., non-toxic, phosphate free, biodegradable, other alternatives to standard teak cleaners, varnishes and solvents). Always follow the instructions on the label and test the product in an inconspicuous area. check box for Regional Best Management Practice
  • Use cleaning products sparingly and only when “elbow-grease” is not working. Even “friendly” products impact the environment. For example, detergents found in many boat cleaning products will destroy the natural oils on fish gills, reducing their ability to breathe. See Resources and Tools: Tip Sheets for examples of non-toxic cleaning alternatives.
  • Keep boats waxed. A good coat of wax will prevent surface dirt from becoming ingrained in the hull and makes boats easier to clean later.
  • As described in Section 1: Work Areas and Boat Hull Washing of this Unit, wash boats on land in a contained area where the wash water can be collected and treated.
  • Wash boat hulls above the waterline by hand using a soft sponge and frequently enough so that the need to use cleaners will be reduced.
  • Avoid using caustic cleaners such as bleach, ammonia, or lye. Do not use petroleum-based cleaning products.

Minimize Impacts of Painting and Coating Operations

  • Restrict spray painting, spraying of fiberglass or other chemicals unless it is done inside of a designated shop, in a spray booth or under a tarp. check box for Regional Best Management Practice

Painting Operations

  • Restrict painting outside of designated shops to the use of rollers and brushes, with proper use of tarps and tenting to protect the surrounding area. check box for Regional Best Management Practice
  • Develop a painting policy to minimize environmental impacts of painting operations (e.g., include a statement about how you are incorporating BMPs in contract language). check box for Regional Best Management Practice
  • If allowed, limit in-water painting to small jobs. Any substantial painting should be done on land, in the boat maintenance area, and/or over a ground cloth. If painting with a brush or roller on the water, transfer the paint to the boat in a small (less than one gallon), tightly covered container. Small containers mean small spills.
  • Mix only as much paint as is needed for a given job. Consider sharing leftover paints with customers or setting up an exchange area for customers to swap unused items.
  • Mix paints, solvents, and reducers in a designated area indoors or under a shed and far from the shore.
  • Keep records of paint use to show when excess paint was mixed for a job. Use the information to prevent over-mixing in the future.

Spray Painting
In some cases, spray painting is the only practical choice of paint/solvent application. As discussed, you should conduct all spray painting on land, in a spray booth or under a tarp. Prohibit or restrict spray painting on the water. Minimize the impact of spray painting by following these recommendations:

  • Approval of spray booths may be required by the local fire department and the local building code authority. Ensure your operation is in accordance with the requirements of your state fire code. check box for Regional Best Management Practice
  • Schedule your spray-painting jobs to minimize coating changes. Fewer changes mean less frequent purging of the spray system. Order your work light to dark.
  • Reduce paint overspray and solvent emissions by minimizing the use of spray equipment.
  • Use equipment with high transfer efficiency. Tools such as high-volume, low-pressure (HVLP) spray guns direct more paint onto the work surface than conventional spray guns. As a result, less paint is in the air, less volatile organic compounds are released, less paint is used, and cleanup costs are reduced. Air atomizer spray guns and gravity feed guns are other types of highly efficient spray equipment.
  • Educate personnel on how to properly operate spray equipment to reduce overspray and minimize the amount of paint per job.

Paint Stripping

  • Consider alternatives to chemical paint stripping depending on the characteristics of the surface being stripped, the type of paint being removed, and the volume and type of waste produced. Alternatives include scraping, sanding, and/or abrasive blasting.
  • Use a heat gun to remove paint and varnish where appropriate.
  • If paint strippers must be used, use citrus-based or water-based products, which are less hazardous.
  • Use only the minimum amount of paint stripper needed for a job.
  • Prevent evaporation by using tight-fitting lids or stoppers. Reducing evaporation protects air quality and saves product and money.
  • Reduce the chance of spills during transport by storing unused paint stripper where it is used most in the shop. Place the product on an impervious base.
  • Encourage careful use by informing all workers and operators of the hazardous nature of solvents and the purchasing and recycling costs.
  • Train employees to use less paint stripper, to properly store new and used paint strippers, to use wise cleanup procedures, and to prevent leaks and spills.

Compound Waxing

  • Check all product and purchase products that are non-hazardous.
  • Conduct compounding and waxing away from the water.
  • If possible, use phosphate-free, biodegradable, and non-toxic soap when prepping a hull. When removing tough stains, use only as much stain remover as necessary, or use a more abrasive rubbing or polishing compound.


  • Minimize waste by working with small batches of resin.
  • Many hardeners can be hazardous. Avoid putting liquid hardener in the trash, since it can spontaneously combust when mixed with sawdust and other materials.
  • Store acetone appropriately and refer to the Waste Management and Recycling Unit for more information on disposal requirements.

Teak Refinishing

  • Teak cleaners, which contain acids and caustics, can be toxic to aquatic life when spilled in the water.
  • Avoid teak cleaners containing acids (such as phosphoric acid or oxalic acid) or those labeled “caustic, corrosive, or acidic.” Clean teak with a mild, phosphate-free detergent with bronze wool.
  • If sanding teak, use a dustless or vacuum sander.
  • If possible, conduct teak refinishing in an upland maintenance area. If not possible, use safer cleaners and avoid flushing excess teak cleaner and teak oil into the marina basin.


  • Avoid the disposal problem of leftover varnish by mixing only as much as is needed for a given job. Consider sharing leftover varnishes with customers or setting up an exchange area for customers to swap unused items.
  • Use less hazardous, water-based varnishes that pose less of a threat to human health or the environment.
  • In case of varnish spills on land, use absorbent material for cleanup, and collect any contaminated soils. Spills in waterways should be contained and mopped up with booms or pads that repel water but absorb petroleum.

Minimize Impacts of Anti-fouling Paints

Anti-fouling bottom paints protect hulls from zebra mussels, algae, and other organisms that can interfere with vessel performance. Pesticides and heavy metals within the paints also harm fish and other non-target species. Most paints work by slowly releasing a biocide, generally cuprous oxide (Cu2O).

Copper-based paints are not used on aluminum hulls; the interaction between copper and aluminum leads to corrosion. Instead, tin-based paints (tributyl tin or TBT) are often used on aluminum-hulled vessels. Because tin is extremely toxic, it must be applied cautiously. Concentrations of TBT as low as a few parts per trillion have caused abnormal development in shellfish (EPA). Fish easily absorb tin through their gills and sediments are capable of accumulating high levels of the metal. For these reasons, federal law restricts the use of tin-based paints to aluminum vessels, boats larger than 82 feet (25 meters), and outboard motors and lower drive units. Consult your state for specific guidelines.

Anti-fouling paints can be separated into three general categories: leaching, ablative, and non-toxic coatings.

  1. Leaching Paints. Water-soluble portions of leaching anti-fouling paints dissolve slowly in water, releasing pesticide. The insoluble portion of the paint film remains on the hull. The depleted paint film must be removed before the boat is repainted. Consequently, most leaching paints are solvent-based, making volatile organic compounds (VOCs) a concern.
  2. Ablative Paints. Ablative anti-fouling paints also leach some toxins into the water. The major difference is that as the active ingredient is leached out, the underlying film weakens and is polished off as the boat moves through the water. As the depleted film is removed, fresh anti-fouling paint is exposed. There are several water-based ablative paints on the market that are up to 97 percent solvent free. As a result, levels of volatile organic compounds are substantially reduced as compared to solvent-based paints. Since they are water-based, cleanup is easier as well.
  3. Nontoxic Coatings. Teflon, polyurethane and silicone paints are nontoxic options. All deter fouling with hard, slick surfaces.

License Requirements for Painting with Anti-fouling Paints

For marinas that apply anti-fouling paints to boats, the state will often impose licensing and certification requirements. These requirements are often dependent on whether the marina is applying the anti-fouling paints in a for-hire status and whether the anti-fouling paint is a restricted-use product.

  • Adhere to your state’s training and licensing requirements (if applicable) for the application of anti-fouling paints. Annual pesticide applicator license and pesticide application business license typically required.

For more information, see your State Laws page.

Use of Anti-fouling Paints

  • Use and recommend anti-fouling paint with minimal environmental impacts (e.g., paint that contains the minimal amount of toxic ingredient necessary for the expected conditions).check box for Regional Best Management Practice
  • Avoid soft ablative paints. check box for Regional Best Management Practice
  • Use water-based paints whenever practical.check box for Regional Best Management Practice
  • Stay informed about anti-fouling products like Teflon, silicone, polyurethane, and wax that have limited negative impacts. Inform your customers about such paints. check box for Regional Best Management Practice
  • Store boats out of the water, where feasible, to eliminate the need for anti-fouling paints.
  • Waste anti-fouling paints containing pesticides, solvents, or metals such as barium, chromium, cadmium, or lead may need to be disposed of as a  Resource Conservation and Recovery Act (RCRA) hazardous waste. Hazardous waste anti-fouling paints cannot be mixed with non-hazardous paints (e.g., latex) for disposal.

Boat Disposal

  • Empty the boat’s fuel tanks and reuse unused gasoline or dispose of it as hazardous waste.
  • Remove and recycle the following boat parts and fluids: used oil and antifreeze; boat engine (recycle as scrap metal) and any metal with recyclable value, such as lead, zinc, aluminum, and copper; and appliances or HVAC equipment containing refrigerants.
  • Remove all mercury-containing devices (e.g., electronic equipment, bilge pump switches, old ship’s barometers, fluorescent lights) and manage as universal waste. For more information see: Waste Management and Recycling Unit.
  • Reduce the size of the hull into smaller pieces as directed by the receiving solid waste facility.
  • The smaller the pieces, the easier it is for the facility to take. Measures should be taken during this process to control fugitive dust. Many marine products contain toxic materials that may become airborne.

Educate Boaters about Responsibilities

  • Download, copy, and distribute Boat Maintenance and Repair Boater Tip Sheets found in the Resources and Tools: Tip Sheets.
  • Inform your patrons when and where they should dispose of their boat maintenance waste, recyclable materials as well as any hazardous waste
  • Post signs throughout the boatyard describing best management practices that boat owners and contractors must follow.
  • Mark designated work areas with signage and, if applicable, use marina rules or contracts to describe how patrons may use the area.
  • Develop a policy for hazardous and other waste collection and disposal. Post notices informing your tenants of this policy.

Next: Section 3: Handling Chemicals