Careful How You Drain that Swimming Pool

The TMACOG Stormwater Coalition provides helpful information for people draining pools and hot tubs in preparation for cooler weather.

Many pool owners don’t know that draining pool water directly to the storm sewer can harm local creeks, rivers and lakes and the fish and wildlife that live in them. This is because pool water contains chlorine, copper, and filter backwash that, when discharged to a storm sewer, runs directly to ditches and streams without being treated.

Discharging chlorinated water through your sanitary drain is the best option because this allows the water to be treated before it enters natural water bodies. In most cases, the sewer rate is based on water use when you filled the pool, so you will not be charged an additional fee. On the other hand, you could incur fines for improperly draining pool water to the storm sewer. If your only option is to drain pool water to a storm sewer, use the steps below to avoid fines and make sure that your end of season pool maintenance does not harm our local waterways.

Step 1: Rest water. Let water sit for two weeks after the last chemical treatment to allow chlorine to break down and leave the water. Allow suspended solids to settle out of the water by keeping swimmers out of the pool for a week prior to draining. The water should not appear murky once suspended solids are settled out. Skim all leaves and algae from the water’s surface.

Step 2: Test water. Before draining, water should be near neutral (pH6.5-8.5) and free of chlorine, bromine and algaecides before discharging. Test kits are available at pool supply stores.

Step 3: Use water for irrigation. As much as you can, allow water to infiltrate through grass, gardens, or other permeable surfaces. You can use a hose to evenly distribute and direct water. Stop draining when lawn and vegetation are saturated and water begins to pond. Do not allow water to drain onto your neighbor’s property.

Step 4: Drain remaining water. After saturating grass and other vegetation, the remaining de-chlorinated pool water can be drained directly to the storm drain. To prevent soil erosion, make sure that water does not flow over bare soil. Only clear water should be flowing into storm drain. Settled solid materials should be properly disposed of in regular trash or compost and should not be discharged with pool water.

Step 5: Properly store chemicals. To avoid stormwater pollution and injury all chemicals should be sealed and stored off the ground away from potential moisture and water. Follow all storage instructions provided on bottles. When time comes to dispose of chemicals, contact your county hazardous waste disposal facility.


Toledo Metropolitan Area Council of Governments | www.tmacog.org