If you have a swimming pool or hot tub, you know that you need to keep pool chemicals around to balance the chlorine and pH levels of the water. Failing to maintain the proper chemical balance in a pool can make people sick, cause injuries and leave you with an icky-looking body of water. However, pool chemicals themselves can also cause injuries — some of them pretty severe. It is very important to store and handle pool chemicals correctly, and to properly recycle them when you are finished with them. If you have pool chemicals you no longer need, plan to either give them away to someone else who has a pool or take them to your local hazardous waste disposal facility.

What are pool chemicals?

Chlorine, which prevents bacteria from breeding in pools and hot tubs, is one of the most common pool chemicals. Bottles labeled “chlorine” also contain calcium or sodium hypochlorite, known as microbial pesticides, which help keep the water free of critters that can cause diseases. Chlorine is very effective, but it is also an extremely hazardous material. It can burn your skin and eyes, irritate your lungs and emit poisonous gas. In order for chlorine to do its job, your swimming pool water needs to have the proper pH level. Swimming pools and hot tubs with an improper pH level can irritate people’s eyes and cause painful, itchy skin rashes. Muriatic acid (or hydrochloric acid), sodium bisulfate, sulfuric acid and nitric acid are all chemicals that will help lower the pH — and all are acids, meaning they are quite caustic. Sodium carbonate or sodium bicarbonate (aka baking soda) will both raise the pH of a swimming pool and are fairly benign. People put various other chemicals in their swimming pools, including algaecides to prevent algae from growing on the bottom and side of the pool; “shock” (a concentrated form of chlorine) to help keep the pool water clear; and clarifiers that help remove dirt. All of these (with the exception of baking soda) can harm humans and animals and cannot go in your trashcan.

How to recycle pool chemicals

If you know someone else who has a swimming pool or hot tub, see if they are interested in your old pool chemicals. They are not cheap, and your friend or neighbor may be grateful to get them for free. However, keep this in mind before you give those old pool chemicals away: Swimming pools and hot tubs use the same types of chemicals, but it is important not to use chemicals formulated for a swimming pool in a hot tub. Swimming pool chemicals contain some different components that can damage hot tubs over time. If you need to dispose of your pool chemicals, they will need to go to your local household hazardous waste facility for recycling. The website for San Joaquin County (which includes Stockton, CA) offers a whole page on pool chemical recycling that provides links to household hazardous waste locations and information about what items they will accept. Most counties should have a household hazardous waste facility; use 1800Recycling’s search tool or call your local solid waste district to find the address. Pool chemicals typically come in plastic bottles, but do not plan on recycling them, even if your community accepts plastic bottles through its curbside program or at a recycling center. Most solid waste districts ask people to keep bottles that contained hazardous materials out of their recycling bins. Make sure the bottles are completely empty, then throw the bottles and the lids in the trash.

How to properly store and handle pool chemicals

When storing pool chemicals, it is extremely important to keep them dry and not allow them to get too hot. Moisture and heat are both elements that can trigger bad reactions, such as fires and toxic fumes. Place pool chemicals on a shelf away from windows, doors or anywhere else they could get wet. Make sure you close the containers securely, and replace cracked or broken containers as soon as you spot them. Do not store them in an area that gets extremely warm. It is never a good idea to mix chemicals together, even if they are same type. Even though the different types of substances end up mixing in the pool, putting the concentrated versions together can cause fires. If you have a partially empty container of a pool chemical, do not add it to a new container; that can also lead to problems. Make sure you know what to do if pool chemicals get in your skin or your eyes. Consider posting that information near the chemicals if people unfamiliar with pool chemicals might handle them. Also, if your pool chemicals do cause a fire, do not try to extinguish it yourself. Chlorine fires in particular are tough to put out and can react with the chemicals in fire extinguishers. Call the fire department immediately and await instructions. For more advice on the best ways to store and handle pool chemicals, check out this publication from the U.S. Environmental Protection Agency.