Wednesday, Oct. 19, 2011 – Protecting your pool for the winter is important at this time of year. Doing so in a way that protects local waterways – and Lake Ontario – is equally important.

Pool owners must clear water from lines leading into their pools to get ready for winter. As a result, most pools need to have some water drained out before the weather freezes.

“Pool water may be safe for swimming,” said Lincoln Kan, Manager of Environmental Services, City of Mississauga, “but because it contains chemicals, such as chlorine or salt, the water itself needs to be regarded as wastewater and treated before it hits Lake Ontario.”

If a pool is drained directly into a storm sewer, it is essentially pouring straight into the lake, which is the drinking water supply of eight million of people. Because of the size of most residential pools, even lowering the water level a little bit can mean a substantial amount of water must be disposed of. Multiply that by the number of pools in any given neighbourhood and pools can become a major contaminant source for watercourses and for Lake Ontario.

“Chemicals in the water not only affect our drinking water, but they also disrupt wildlife by inhibiting plant growth, impairing reproduction, and reducing the overall diversity of organisms,” said Kate Hayes, Project Leader, Restoration and Stewardship, for Credit Valley Conservation (CVC).

To drain a pool safely takes some time, but rushing the process not only harms the environment, it can create flooding or sewage backups in the neighbourhood. The City of Mississauga offers the following tips:

• Direct water from the pool into a sanitary drain in your house – such as the laundry room sink.

• Chlorine pools should be left untreated with chemicals for seven to 10 days before any draining takes place. The chemicals dissipate making the water much safer.

• Saltwater pools, which are increasingly popular, must maintain a certain concentration of salt in order to function properly. The City now recommends a 1 ½” hose, directed into a drain in the house, for draining saltwater pools.

• Experts also caution that water not be pumped too quickly or through too large a hose to reduce risk of flooding or back-ups.

• Choosing non-peak times, such as evenings after 8 p.m. or weekends after 10 a.m., to discharge water also helps reduce these risks.

The City of Mississauga and the Region of Peel prohibit residents and pool companies from opening sanitary drains in the road, as this can cause sewage back-ups and are also a road hazard. More tips on safe pool maintenance are available at\livinggreen. Taking action on pools is just one way residents can help protect our waterways and Lake Ontario.

CVC is taking action through development of a Lake Ontario Integrated Shoreline Strategy (LOISS), which will work with the community to find ways to protect the water quality, quantity and wildlife habitat of this important natural resource. To learn more about CVC action on water resource protection, visit


Conservation Authorities are a provincial/municipal partnership. CVC was established by an act of the province in 1954 with a mandate to protect all natural resources other than minerals in the area drained by the Credit River. We have been working for over 50 years with our partner municipalities and stakeholders to protect and enhance the natural environment of the Credit River Watershed for present and future generations.

Media Contacts:

Marta MarychukKate Hayes
Acting Supervisor, CommunicationsProject Leader – Restoration and Stewardship
Credit Valley ConservationCredit Valley Conservation
905-670-1615 ext. 224905-670-1615 ext. 428
[email protected][email protected]
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