It was a pleasant morning in early summer when a boat owner we'll call Dave stepped aboard his boat. He'd invited friends for an afternoon cruise, and the warm weather promised to make the day perfect. He went through his usual routine: opened up the hatches, flipped on the engine blower and the bilge pump, and put the cushions in the cockpit. As he was finishing up his chores, he realized that two uniformed Coast Guard officers were standing on the pier next to his boat.

"Good morning, sir," one greeted him, "Is this your boat?"

Replying that it was, Dave had the uneasy feeling that all was not right with the world.

"Sir, we are going to have to cite you for violation of the Federal Water Pollution Control Act, and if you'll step over here, I'll show you why."

Looking where the officer was pointing on his hull, Dave saw that his bilge pump was coughing a few last spurts before shutting off. Still scrupulously polite, the officer said, "As you can see by the film on the water, you've been discharging oil into the water, which is strictly prohibited. Now if I could see the registration papers and some personal identification, please." As he spoke, the other officer produced a Polaroid camera and snapped a few different angles of the now widening rainbow-hued sheen.

After signing the citation, Dave sat in the cockpit to read the small print and his heart stopped. The fine was no slap on the wrist — it could be as high as $5,000! Though he was no Exxon Valdez dumping millions of barrels of crude oil in the water, Dave was just as guilty of breaking the Federal water pollution laws.

In all likelihood, you are, too.

Dave's woes stemmed from two separate problems. Like most boat owners, he enjoyed doing his own maintenance and, in the process of changing an oil filter, he had dribbled a couple of tablespoons of oil under the engine. He also had a prop shaft that was dripping just enough to produce a couple of inches of water in the bilge during the week, which wasn't even enough to activate the automatic bilge pump. When he flipped the bilge pump switch to empty out the water, Dave was asking for trouble and he got it. He has now hired a lawyer to plead his case.

The Bottom Line

Though the Federal Water Pollution Control Act was passed in 1972, it hasn't been enforced in the pleasure boating community with any vigor until the past few years. Today, if you own a boat, you are probably violating that law and therefore liable for some sizable fines.

The Federal limit set by the EPA is 15 parts of oil per million parts of liquid discharged from your boat, which means that you would need to have more than 500 gallons of water in your bilge (picture this as ten 50 gallon drums) to legally remove one fluid ounce of oil without breaking the law. In addition, each state is allowed to set their own lower requirements, and Florida allows only 5 ppm (or about 1,500 gallons of water per ounce of oil). California and New Jersey permit zero ppm. Adding to the problem is that, after being cited, you are guilty until proven innocent and you must prove that your liquid discharge did not exceed the legal limit.

It is, of course, very difficult to keep oil from getting into the bilge of a gas or diesel powered boat. Even if you don't have an oil leak (who doesn't?) or if you are able to keep the drip pan under the engine separate from your bilge water, you may still have "blow-by" oil that exudes from the oil breathers, collects on the bilge surfaces, and eventually ends up in the bilge water.

Is There A Solution?

Bear in mind that having oil in the bilge is not illegal, although it can be both smelly and dangerous. Pumping it into the water on which you float is the illegal part, and that's where boat owners need to take great care to avoid citations like Dave's. Simply having an automatic bilge pump to protect your boat can get you in trouble.

If you have a trailerboat, you can simply drain the bilges at home but, then again, you're probably breaking the law because it is illegal in most areas to dump oil into the sewer system, regardless of whether you pour it down your kitchen sink or into a storm drain. Unlike your old engine oil, most oil recycling companies won't accept your liquid because it is mostly water. You can drain the oily bilgewater into a container, which you then take to a company that disposes of industrial wastes and pay them to get rid of your bilge water.

If your boat is in the water, you need to do two things: first, keep oil out of your bilge and, second, remove it immediately when it does get in the bilge. Removal, of course, doesn't mean pumping it overboard.

Bilge Cleaners

There are an array of so-called "bilge cleaners" available at your local marine hardware store, all of which guarantee to turn your bilge into a clean and fresh-smelling flower garden. Since oil and grease don't mix with water, most of these bilge cleaners are designed to emulsify oil and water into one homogeneous liquid that can be pumped out. They include a detergent to loosen grime and dirt from the bilge surfaces at the same time, and usually an aromatic to make you think you're in the mountains.

Nearly all of the bilge cleaners now available are labeled as "biodegradable," meaning that the majority of the materials in the product can be consumed by some natural life form without ill effects. Unfortunately, just because the bilge cleaner is biodegradable doesn't mean that the solution of oil and bilge cleaner is biodegradable. The oil is simply being held in suspension, and it is still just as illegal to pump overboard as it was when it floated on the surface of your bilge water.

Interestingly enough, most of the label instructions on bilge cleaners dance lightly around what to do with the emulsified liquid. One reminds you to "note all laws regarding oily discharge," West Marine's label gives the illegal advice to dump the liquid into a municipal sewer system, and others don't address the question at all.

Bacteria Warfare

There are several companies that produce bacterial bilge cleaners, which may (or may not) provide a solution. Certain types of bacteria (including some genetically engineered by General Electric) live in water and eat petroleum products, converting them back into water and carbon dioxide. These companies are supplying colonies of the bacteria in a solution that you deposit in your bilge. Developed to handle major oil disasters such as the Exxon Valdez, these micro-critters will theoretically gobble up your oil problem.


There appears to be a downside, and Starbrite (which was considering adding a bacterial bilge cleaner to their line) did some extensive testing and, based on their findings, decided that the possible hazards outweighed the positives.

The owner of a 27-foot powerboat who used a bacterial bilge cleaner quickly discovered the smell of rotting eggs, an indication of the presence of hydrogen sulfide gas, which then turned into an attack on the electrical and electronic system aboard his boat.

As it turns out, both gasoline and diesel fuel still contain a percentage of sulfur, and the bacteria reduced these sulfur compounds to hydrogen sulfide. As a result, all of the metallic surfaces inside his boat turned black, and his multi-strand electrical wiring developed resistances which interfered with the systems. As a result, he had to tediously clean all of the terminals and do a considerable amount of rewiring. The bilge may have been clean, but the effort negated the result.

Additional problems are incurred with bacterial bilge cleaners, since they require a fairly long period to consume the oil and you have to keep your bilge wet during that time.

The worst news, however, is that you still can't pump the bilge overboard, because the EPA still feels that the oil, whether in the critters tummies or not, is still oil. Besides, there is no easy way to monitor the appetite of the bacteria to determine what stage of oil decomposition has been reached at the time you flip on the bilge pump.


Sadly enough, there is no good answer to dealing with oil in your bilge. Bilge cleaners only emulsify it so you can pump it out, but then where do you take it? Bacterial cleaners may cause other problems, and still aren't legal to pump overboard. The answer lies in prevention, and here you do have some control over the situation.

To start with, keep your engine leak-free. Valve cover and oil pan gaskets are the usual culprits on gasoline engines, and they can be usually be replaced fairly inexpensively when you get your annual tune-up. Transmissions are also notorious for oozing droplets, and you'll need to be careful when you change your oil and filters. You can even put a drop or two of oil in the bilge if you aren't careful when pulling the dipstick to check the oil.

If your bilge doesn't have a separate pan under the engine to separate any drippings from the bilge water, you can provide your own makeshift drip pan. An aluminum baking tray is inexpensive and can be found in sizes that fit under most engines, or you can use a cheap plastic liner for paint roller trays that cost pennies at a hardware store.

If you're still getting oil in the bilge, several companies are offering oil absorbent materials that can be used to suck the oil right out of the bilge water, leaving a liquid that you can pump overboard with no fear. Starbrite, for example, offers an 18-foot by 18-foot Engine Drip Pad that can be secured under the engine to absorb up to 3 quarts of petroleum, but which repels water. Starbrite also has a Bilge Oil Absorber about the size of a loaf of bread that can be lowered into the bilge to inhale two quarts of oil. Most marine hardware stores offer these or similar products from 3M in a variety of pillow, sheet and boom shapes to fit your oil spill needs.

Your first line of defense is prevention, and your second best protection against a citation is to make a clean and oil-free bilge a priority on your boat.