In order to protect the environment and the City’s waterways, there are mandatory requirements on how to discharge water from pools, hot tubs and spas. These requirements must be followed by pool owners and those hired to maintain them. The requirements differ depending on the type (chlorine or salt) and if the pool is private or commercial.

Dangers of Water from Chlorine and Salt Water Pools

The water from pools is filled with chemicals that keep them clean and safe for swimming. The main chemicals found in pools are chlorine, bromine, salt, copper-based algaecides, nonylphenols and nonylphenol ethoxylates. These chemicals are harmful to fish and organisms that live in creeks and rivers across Toronto and Lake Ontario. Pool water can never be discharged into or onto the ground near a ravine or valley; it will cause erosion to the land banks and serious damage to vegetation.

Spills

You or your hired pool service provider are legally obligated to report a spill to provincial and municipal authorities if your pool water has been spilled into a stream, river, lake or the storm sewer system (without proper treatment). To report an improper discharge, call 311.

A private pool, hot tub or spa is one that serves five or fewer single-family residences.

The City’s pool discharge requirements are set out in the Environmental Best Management Practices (BMP) for Private Swimming Pools and Hot Tubs/Spas. This BMP will provide you with what you need to know about operating your pool, hot tub or spa in compliance with the City’s Sewers By-law and the BMP.

Proper discharging of pool, hot tub or spa water

Chlorine pools

Water from chlorine pools can be:

  1. Discharged to the storm sewer system.
    • Water must be dechlorinated first.
    • Discharge should not be done on a rainy day as it will overwhelm the storm sewer system.
  2. Discharged onto a permeable surface on your property.
    • Water must be fully absorbed into the ground on your property without flowing onto any neighbouring properties.

Salt water pools

The water from salt water pools has such high levels of chlorides that it cannot be discharged to the storm sewer system. Alternatively, the water can be:

  1. Carefully discharged to the sanitary system connection located on your own property.
  2. Discharged onto a permeable surface on your property.
    • Water must be fully absorbed into the ground on your property without flowing onto any neighbouring properties.
  3. Hauled by a Ministry of the Environment and Climate Change approved hauler.

Water from pool covers and filters

Rainwater or melted snow collected on your pool cover can be discharged to the storm sewer system as long you remove leaves and other debris first.

The backwash water from the filter must be filtered and dechlorinated if going to storm sewers, otherwise it must be discharged to the sanitary sewer or onto your surrounding property if it can be properly absorbed into the ground.

Storm sewer limits

Chemical Amount
Chlorine 0.01 mg/L or less
Bromine 0.01 mg/L or less
*Copper 0.04 mg/L or less
**pH 6 to 9.5

*Note: mg/L = milligrams per Litre; equivalent to parts per million (ppm)
**Note: Muriatic Acid cleaning must be neutralized to the City’s Storm Sewer pH limits before discharged to the storm system. Muriatic acid may harm plants and animals.

Any pool, hot tub or spa that serves five or more units or suites. For example: a pool at an apartment building or community centre.

Proper discharging of pool, hot tub or spa water

Under the Sewers By-law, commercial pools, hot tubs and spas must discharge into a sanitary connection on the same property that they are situated. A sanitary connection carries water to the City’s wastewater treatment plant before it is released into Lake Ontario. Commercial pools are also regulated by Toronto Public Health and Ontario Regulation 565, Public Pools.

The only water from a commercial pool, hot tub or spa that can enter the storm sewer is rain or melted snow trapped, for example, on a pool cover, after the sediments and leaves are removed.