Swimming pool owners and operators can help protect local streams and rivers by following these guidelines for draining (discharging) swimming pool water.

Chlorinated or brominated swimming pools

may be drained to a County storm drain or a stream after taking these steps:

1. 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.
2. 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.
3. Ensure the water is clear and free of algae, sediment, sticks, leaves, or other pollutants.
4. Release the dechlorinated (or debrominated) water before adding products to winterize the pool.
5. 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.
6. 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 Wastewater Management at 703-324-9389 before discharging backwash to the public sanitary sewer system.

Salt Pools

should not be discharged to a storm drain or stream. Fairfax County 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:
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  • 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.
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  • Do not drain water from a salt pool into a septic system.
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• Use a licensed sewage handling service to dispose of the salt pool water properly.

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

County regulations. Chapter 124.1 of Fairfax County Code, also known as the Erosion and Stormwater Management Ordinance, prohibits the discharge of substances other than naturally occurring surface or subsurface waters to Fairfax County’s storm drainage system and waters of the state unless it is authorized by a state permit.  Dechlorinated pool water is authorized by the state.  Violating the Erosion and Stormwater Management Ordinance may result in a civil penalty.

Threats to aquatic life.  Chlorine, bromine, salt, and other pool chemicals that are used to keep swimming pools safe for people may kill fish and other aquatic life in streams.  Stagnant pool water may kill aquatic life if it contains too little oxygen when it flows into a stream.

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.

For More Information

Call the Stormwater Planning Division at 703-324-5500, TTY 711, or email StormwaterPollution@fairfaxcounty.gov about residential swimming pool guidelines or to report improper pool discharges.  Commercial swimming pool operators, please call the Fairfax County Health Department at 703-246-2300, TTY 711 or visit Swimming Pool Codes and Permits.