Swimming pools, by state law, may not be discharged into a stormwater system if chlorine has been added within the previous seven days. If the water has been analyzed and it can be shown that the discharge would not contain a concentration greater than 0.05 milligrams per liter of chlorine residual, it may be discharged.The stormwater system includes anything that would convey the water into a pond, lake, or stream. This includes a resident’s backyard if it drains outside the property lines. The chlorine discharged can damage aquatic life in lakes and streams as well as pose a hazard to other residents downstream. Swimming pool discharge should never be released in such a way that it would inconvenience adjacent properties.