Safely Discharging Swimming Pool Water

Have you noticed lots of swimming pools, large and small, being installed this year? Most likely caused by the closing of many public pools due to COVID. Labor Day weekend is the time many homeowners choose to winterize their swimming pools. Some will take their pool down completely, while others will simply drain a small amount of water and cover it until next year.

Unfortunately, the same treatment options that make your pool safe to enjoy, chemicals (chlorine or bromine), or minerals (salt), can be harmful to the environment, and require you to take precautions when discharging pool water or backwash.


  • Public wastewater treatment plants and private septic systems rely on microorganisms as part of their process. Any discharge that could potentially harm these microorganisms could have adverse effects on the systems. These microorganisms are particularly sensitive to salt.
  • Aquatic life and some vegetation can’t survive chlorine, bromine, or salt at the levels required in swimming pools.
  • Keep in mind that the storm drain system, made up of catch basins, pipes, and ditches all drain untreated to waterbodies where aquatic life could be affected.


  • For chemical pools (bromine or chlorine): Prior to discharge, let the water sit for 2 – 4 days checking the levels until the concentration is less than 0.1 ppm (mg/l).PoolCopy
  • For saltwater pools: Saltwater pool water must be desalinated prior to discharge. Freshwater is less than 1,000 ppm while saltwater pools are around 3,200 ppm. Dilute with freshwater to an acceptable concentration (less than 1000 ppm) or use a commercial treatment process.
  • If discharging to a wastewater treatment plant, at any concentration, contact them prior to discharge for any pretreatment requirements.
  • If discharging to your septic system, or on the ground of your property, make sure the chemicals or salt are at an acceptable level.
  • If discharging to your land, or at a point that leads to a storm drain system, make sure the chemicals, or salt are at an acceptable level. Contact the owner (municipalities, villages, county or state) of the storm drain system prior to discharge to ask about local requirements.


  • Consider having your swimming pool pumped by a professional service.
  • Soil that has been contaminated with salt can be treated with gypsum. Consult with a landscape professional for soil treatments or replacement.
  • After removing saltwater pools, apply 2 inches of water to the location.
  • Be a good neighbor and keep water on your own property.
  • Avoid soil erosion…. release water slowly.
  • Consult with your pool manufacturer for recommendations.

For additional information contact Kathy Davis 740-885-3312