Even at extremely low amounts the chemicals used to maintain pools and hot tubs can hurt plants and aquatic life in our lakes, rivers, creeks and wetlands.
POOL AND SPA TERMS AND IMPACTS TO WATERBODIES
Chlorine - Chlorine is used to sanitize swimming pools. It is very toxic to fish, damaging their gills and causing fish to drown.
Bromine - Bromine is also used to sanitize swimming pools, but it does not break down over time like chlorine does. In high doses it causes many of the same effects to fish as chlorine.
Copper - Copper is used to kill algae in the filter system. It is very toxic to fish and can cause reproductive problems as well as tissue damage. Copper may also kill the algae that aquatic life need to eat.
pH - pH is a measurement of how acidic or basic the water is. Fish have a pretty narrow range of tolerance before they die. The ideal pH for aquatic life is between 7 and 8. Many times the pH in a pool is within this range. However small rapid changes in pH, from draining your pool, can cause serious health problems or death for aquatic life.
Temperature - Pool water can be very warm compared to river water. The sudden shift in temperature caused by draining pool water can affect the health and survival of aquatic life.
Drain your pool or spa in accordance to SMC Chapter 13.30:
Drain to vegetated areas that may infiltrate into the ground. If vegetated areas are not available, reduce chlorine in the pool water to undetectable levels (<(less than) 0.1 mg/L). Consider the following options for removing chlorine:
Discharges should be cooled to prevent in increase in temperature to receiving water. Swimming pool cleaning wastewater and filter backwash shall not be discharged to the storm drain system.