Proper Discharge of Swimming Pool Water

Draining of swimming pools into street gutters and storm drains or directly into the sanitary sewer system can impair water quality of our drinking water sources.  Pools, hot tubs, and fountains often use chemically treated water; however, most of the chemically treated water discharged into storm drains – and ultimately water bodies – is from residential swimming pools.

Pool / Hot Tub Owner Survey

Violations May Harm Aquatic Life & Result in Civil Penalty

Discharging swimming pool water the wrong way may harm the environment and violate regulations.

Chemicals that are used to treat swimming pool water, such as chlorine, bromine, and algaecide, adversely affect fish and other aquatic life in streams when these chemicals are not sufficiently removed prior to backwashing or draining.

Pool backwashing – whether commercial, public, or privately-owned – is performed regularly during the summer by draining pool water through the filter and out of the pool to remove accumulated debris. Some pools are drained when closing for the winter to prevent freezing of pool water and damage to pool fixtures. Both of these discharge activities may pose significant environmental impacts when directed to the storm drain or sanitary sewer system.

City/County Regulations. The Stormwater Management Ordinance prohibits the discharge of substances other than naturally occurring surface or subsurface waters to the storm drain and other waters unless it is authorized by a state permit.  Dechlorinated pool water is authorized by the state.  Violating the Stormwater Management Ordinance may result in a civil penalty.

Stream bank erosion.  Draining water from swimming pools too quickly can cause erosion of the stream bed and banks, especially in smaller streams.  Erosion can damage habitat and water quality. Recommended draining rates are 12-15 gallons per minute (gpm) with a maximum rate of 25 gpm to storm drains or streams.

Guidelines for Draining Swimming Pools

Swimming pool owners and operators can help protect local water sources, as well as the sanitary sewer system, by following these guidelines for draining (discharging) swimming pool water.

Chlorinated or Brominated Pools

• Residents may not open a manhole cover to drain pool water into the sanitary sewer system.
• Remove the chlorine or bromine by allowing it to dissipate or by adding a chemical agent.  Allow pools to sit 7-10 days for chlorine or bromine to dissipate.  Sodium thiosulfate may be used to remove chlorine more quickly.  Before discharge, test the pool water to ensure the total residual chlorine or total residual bromine level is less than 0.1 mg/L.
• Test the water to ensure the pH level is between 6.0 and 8.0.  Adjust the pH, if necessary, to achieve an acceptable level.
• Ensure the water is clear and free of algae, sediment, sticks, leaves, or other pollutants.
• Release the dechlorinated or debrominated water before adding products to winterize the pool.
• Drain the water over pervious, well-vegetated ground on the owner’s property, if possible.  Avoid draining pool water directly into a storm drain or a stream except as a last resort.  As a courtesy, avoid draining pool water across neighboring properties and creating puddles, standing water, or ice.
• Likewise, ensure that filter backwash is free of chlorine or bromine, sediment, and scum and has an acceptable pH level before discharging it to storm drains or streams.  
• If you are unable to remove chlorine or bromine, small amounts of backwash water may be discharged to the public sanitary sewer system through a household drain.  Contact PWC’s Liftstation Department at (910) 223-4750, before discharging backwash to the public sanitary sewer system.

Salt Pools

Salt Pools should not be discharged to a storm drain or stream. PWC suggests these options:

• Discharge salt pool water, including backwash water, that is free of debris and sediment, to the public sanitary sewer system through a household drain such as a bathtub, sink or floor drain.  Residents may not open a manhole cover to drain pool water into the sanitary sewer system.
  
  To avoid damage to your property:
  •  Ensure the plumbing is adequate to accept the rate of flow from the pool.  Check with a licensed plumber before draining pool water into a sanitary drain.
  •  Do not drain water from a salt pool into a septic system.
• Use a licensed sewage handling service to dispose of the salt pool water properly.

Report Illegal Dumping or Spills

• PWC Environmental System Protection: (910) 223-4699.