Pet Poo & Bacteria

Fecal coliform bacteria are organisms that are common to the intestinal tracts of humans and animals and may cause illness and disease like the deadly E. coli. One gram of dog waste (the weight of a business card) contains 23 million fecal coliform bacteria, almost twice as much as human waste.  With the average 0.75 pounds of waste per day (340 grams), we’re talking 7.82 billion fecal coliform bacteria per day, per dog!

Pet waste can also transmit viruses and parasites, including tapeworm, roundworm, Parvo, and more.  Humans who come into contact with dog waste could contract campylobacteriosis, salmonellosis, and toxocarisis, which may cause abdominal cramps, fever, coughing or wheezing, hives, and possibly permanent vision damage.  

Poo left in a yard takes more than a year to fully decompose, and every time it rains, another load of pollution is sent to the waterway. A 1993 US EPA study showed that 95% of fecal coliform found in urban storm water was of non-human origin. And studies in Seattle, Washington, found that nearly 20% of the bacteria isolates researchers could match with a host animal were matched with dogs. And dog poo is not a good fertilizer, so don’t leave it around to feed your lawn.


While pets are a major contributor of bacteria to our water, they are not the only source.  Read on to find out how you can make a difference beyond your backyard!

  • Don’t feed the geese! Geese, swans and other waterfowl present in large numbers contribute a heavy load of waste to our water.  Help reduce their impacts by not feeding them or otherwise attracting them to your yard.  Besides being an environmental benefit, this action is healthier for the birds as well; the bread people typically feed them lacks in the nutrients and roughage they need in their diets.
  • Keep water on your property! Many cities and towns have combined sewer systems.  This means that storm water (the water that runs off of your roof, sidewalk, streets, etc. during a storm) and wastewater from homes and businesses end up in the same sewer system.  Normally, that water gets treated by a wastewater treatment plant, but in times of very heavy rain, the plant cannot keep up.  In these instances, untreated water is released into our streams and rivers.  Keep water on your property by using rain barrels or rain gardens, and you can lessen the load on the wastewater treatment plants.
  • Unmaintained Septic Systems: Septic systems are small wastewater treatment systems installed for individual homes.  If they are not inspected and maintained properly, they can leak waste and contaminated runoff into our waterways.  Visit the septic system impacts page for more information.
  • If you have livestock or hobby pets (like chickens, goats, peacocks), manage their waste as well! Large livestock operations must have permits and are regulated to ensure they properly dispose of the waste they create.  However, smaller backyard farming operations and hobby pets are often overlooked.  Their waste should also be properly managed to prevent it from contaminating our water.  Collect and pile manure and keep it under cover sheltered from rain and wind, direct downspouts and runoff away from these piles, and/or build a compost system or have an off-site compost facility collect the manure.
  • If you farm, be smart about spreading! Know what amount of manure is needed for your crops and only apply that much!  Do not spread in winter or early spring, on sloped lands, near wetlands or water sources, or in other situations where runoff potential is high.