Your swimming pool, spa or fountain maintenance practices can make a significant difference in the water quality of our creeks, the Napa River and the San Francisco Bay. Many chemicals used in pool maintenance (e.g., chlorine, bromine, copper and silver) are extremely toxic to aquatic life. For example, the California Department of Fish and Game has determined that levels of chlorine in water higher than 0.01 parts per million (ppm) are dangerous to the environment. The typical chlorine level maintained in a pool is 2 to 4 ppm; that is 200 to 400 times the harmful level. By doing a few simple things, you can protect the fish and critters that live in our creeks and comply with local, State and federal regulations. Remember that you are also responsible for the actions of your contractors. Be sure you know how your contractor will be disposing of the pool, spa or fountain water and the filter cleaning rinse-water and backwash.