Raccoons can, and do, poop in the pool.
From Flickr user mwms1916 Raccoons can, and do, poop in the pool.

When the term Accidental Fecal Release (AFR) is mentioned, immediately Recreational Water Illness comes to mind. Protozoan parasites such as cryptosporidium and giardia are common threats, both spread by swallowing contaminated pool water. But what do you do in the case of a Non-People Fecal Release? It would be absurd to dare think that only a person could, or would, go poop in a pool. In fact, there are many non-people creatures that may use your pool as a restroom. After all, a lot of people do allow Fido to swim laps from time to time in their pools. (State pool codes, however, typically prohibit dogs from swimming in public pools, or even being allowed inside the pool barrier.) Aside from the adverse effects on water chemistry, studies have shown that both dogs and cats can contract giardia, though a different type of the parasite that typically infects humans. Additional research has shown that a person is not likely to contract giardia from a domestic animal, but it does state that it is possible.

You may find migrating water fowl visiting swimming pools during their journey either north or south. Germs that can infect humans can be found in bird droppings, especially those from ducks and geese. Possible threats are E. coli, cryptosporidium as well as others. The CDC recommendation is to treat bird droppings in the pool the same way one would respond to finding human feces in the pool.

Frogs are common pool guests. These hopping green bug eaters actually excrete urea through their skin which does contribute, in a small amount, to the organic chloramine level. Chloramines are a weak and ineffective chlorine. Organic chloramines differ from inorganic chloramines in that they cannot be removed by adding additional amounts of chlorine. Unfortunately, urea is not the only concern. The CDC reports that reptiles and amphibians frequently carry a germ called salmonella.

Raccoons are another potential visitor. A pool is very attractive to this masked nocturnal visitor for several reasons. First, the obvious, the little critters get thirsty. Raccoons also like to wash their food; they’ll dunk it in water repeatedly before eating each bite. It is not uncommon for homeowners and pool operators to find evidence that a raccoon has visited a pool during the night as they will often defecate on the pool deck, or more frequently on the top step leading into the pool. Standing in shallow water to defecate is natural for raccoons. It is a way for them to hide their droppings from other raccoons and predators.

Baylisascaris procyonis is a roundworm that commonly lives within the intestines of raccoons. People can become infected by accidentally ingesting baylisascaris procyonis eggs from water that has become contaminated by raccoon feces. Once the eggs hatch, the roundworm can grow to a large size spreading throughout a human body. Although documented cases in humans are uncommon, the risk is substantial and the prognosis is grave with or without treatment. In nature, infected raccoons shed an average of 20,000 to 26,000 eggs per gram of feces and can shed in excess of 250,000 eggs per gram of feces.

The CDC states: Because baylisascaris eggs are particularly tough, adding chlorine to the water will not kill them. If a lab test has confirmed that the raccoon was infected with baylisascaris or you don’t know if the raccoon was infected because the raccoon’s feces were not tested, there are two options for cleaning your pool. Remember to close the pool to swimmers until you have finished cleaning the pool.

CDC Option 1: Filter the pool for a minimum of 24 hours and then backwash the pool filter. Put on disposable gloves to replace the material doing the filtering (if possible). Double bag the discarded material in plastic garbage bags. Remove gloves and place them in the garbage bags. Wash your hands thoroughly with soap and water afterwards.

CDC Option 2: Backwash the pool filter, drain and hose down the pool. Put on disposable gloves to replace the material doing the filtering (if possible). Double bag the discarded material in plastic garbage bags. Remove gloves and place them in the garbage bags. Wash your hands thoroughly with soap and water afterwards. Refill the pool.

Baylisascaris procyonis eggs are 80-85 µm (microns) by 65-70 µm (microns) in size, thick-shelled, and usually slightly oval in shape.  With the ability of swimming pool filters to remove particles that range from 4 microns (DE) to 50 microns (Rapid Rate Sand) in size, the B. procyonis eggs are large enough that they can be removed from the pool water through filtration, followed by backwashing to waste as described in CDC Option 1.

Any fecal release in a swimming pool is a potential health risk -- human feces or animal. Immediate response is always required. If uncertain as to how to handle a potential health threat, remove all bathers from the water, close the pool and call 800-CDC-INFO (800-232-4636).

Methods of prevention when animals are the concern? Well, don’t feed the critters is first and foremost. Move bird feeders, if you have them, far away from your pool. I’ve found adding a floating alligator decoy does a nice job of keeping the raccoons and ducks at bay. Sadly, the frogs will tend to mockingly ride the plastic gator around the pool.