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Why Are Beaches Posted?

It can be a disappointment. You arrive at a beach on a hot summer day looking forward to a cool swim. Then you find signs posted that warn bathers to stay out of the water.

What’s polluting our beaches

Several sources of water pollution can result in beach postings. These include:

  • seasonal and storm surface run-off (heavy rain) into rivers and lakes
  • storm water runoff containing bacteria from pet and wildlife feces
  • storm water runoff from ditches and storm sewers
  • agricultural surface runoff from land near swimming areas
  • runoff from manure piles and feedlots
  • agricultural activities, particularly livestock operations, if not properly managed.
  • illegally connected sanitary sewers and poorly installed basement washrooms
  • domestic septic systems that are poorly maintained and located
  • large populations of waterfowl that colonize a beach or surrounding area
  • environmental conditions (i.e., wind, rain, sunlight, air and water temperature)
  • overflows from combined sewers that carry both sewage and stormwater
  • excess flows that have bypassed municipal or industrial sewage treatment plants.
  • boating waste
  • livestock access to streams
  • milkhouse wash water that is dumped into drainage ditches and streams.

Guidelines for beach postings

Beach Posting Sign
Health Department
Beach Posting Sign

Ontario beaches are posted with warnings when E.coli bacteria measure more than 100 E.coli per 100 millilitres of water. Generally it’s up to the local Medical Officer of Health to judge when a beach should be posted. If bacterial counts exceed the provincial standard, the Health Department will arrange to have signage posted at the beach warning the public that the water is unsafe for swimming.

Beaches are usually reopened when E.coli levels have fallen to an acceptable level of 100 E.coli per 100 mL or less for two or three days.

What are the risks of going into the water?

A beach may be posted because the water has levels of bacteria that increase your risk of developing an infection. The most common are minor infections of the skin, eye, nose, throat and stomach disorders. Those most susceptible to these infections are young children, the elderly and those with depressed immune systems. It is recommended that you do not go into the water if you have an infection or open wound.

Based on health risk data, the chances are less than 1.5 per cent that you will contract a disease such as gastrointestinal illness when swimming in waters that contain as much as 200 EC per 100 mL of water.

In special circumstances a beach will be closed if there are indications of hazardous or infectious materials present in the water or in the event of a blue-green algae bloom.

Watch out for rainstorms

Beach Posting Sign
Health Department
Heavy Rainfall Warning Sign

Beach postings often occur after heavy rains. In urban areas, stormwater washes fecal material from dogs, cats, birds and other wildlife into storm sewers that flow directly into nearby rivers and lakes. In rural areas, stormwater washes fecal matter from livestock operations into nearby streams and lakes. Additionally, high wave action may stir up bacteria settled on the lake bottom.

Many older cities have combined sewers that convey both sanitary sewage and stormwater to a sewage treatment plant. During heavy rains, however, overflows from these combined sewers are discharged untreated directly into rivers and lakes.

In Durham Region all beaches have permanent yellow signs (June - September) posted in one or more locations reminding the public not to swim in beach water for at least 48 hours after heavy rainfall as bacteria levels can increase due to run-off.

How can you help to keep our beaches clean and safe for swimming?

  • Please observe stoop and scoop bylaws. Remove dog feces immediately from the streets, public parks and private property. Pet wastes are a major source of bacteria in stormwater.
  • Where possible, detach eaves trough downspouts so that rainwater goes into the ground rather than into a sewer. This reduces the amount of water going directly into sewers.
  • Reduce water use in your household. This helps avoid overflow problems at some municipal sewage treatment plants that may cause untreated sewage to enter lakes and rivers.
  • Make sure that any washrooms added to your home are properly connected to the sanitary sewer pipes or your private sewage disposal system.
  • Don’t discharge backwash from your pool onto the road. Pool water should be discharged three days after the last chemical application, either to the sanitary sewer, or across the lawn to the storm sewer. By allowing pool water to flow across a lawn, some water will be lost through infiltration and most pool chemicals will evaporate into the air.
  • Consider a driveway of crushed or interlocking stone. An open surface driveway such as this reduces the amount of stormwater entering the sewer system. It also replenishes groundwater.
  • In agricultural areas, fence livestock away from streams and give them alternative sources of water. This benefits the health of both the herd and the environment.
  • Make sure that runoff from feedlots and manure piles is properly contained.
  • Upgrade septic systems and keep them in good working order.
  • Do not attract animals or birds to beaches by feeding them.
  • Practice pollution-free boating by disposing of human wastes hygienically.

Adapted and reprinted with permission of Ontario Ministry of the Environment.