Why are pool chemicals and salt water bad for water quality?
Disinfectants used to keep our swimming pools clean and salt water from new salt water pools are pollutants which threaten our waterbodies. When draining swimming pools, many people release water that is heavily laced with chlorine, bromine or salt water down the street and into the storm drains. The pool chemicals are designed to keep the water in swimming pools sterile, but unfortunately, also kill important parts of the aquatic environment in our waterbodies, too. Salt water pools reduce the need for pool chemicals but can harm fresh water aquatic environments by introducing too much salt to a fresh water system.
What can we do to prevent pool chemicals and salt water from polluting our waterways?
Before draining your swimming pool water into the street, make sure you dechlorinate the water first. Dechlorination will occur if you allow the water to sit for a few days and let the sun shine on the water. If you want to drain the pool in a short period of time you can purchase a dechlorination kit at your local home supply store.
Make sure your filter backwash drains to the sewer system and not into the street. Backwash water has a heavy concentration of chlorine and other chemicals that are good for treating sewage water, but damaging to natural aquatic environments. Additionally, backwash leaves a residue of diatomaceous earth (DE) along the gutter and streets.
If filter backwash cannot be discharged to the sewer, a catch basin should be installed to remove the DE prior to draining it into a landscaped area. The size of the catch basin would have to be large enough to house the DE filters. Then rinse cartridge filters into a container to settle out waste. Bag and dispose of residue in the trash.
Some people have salt water pool systems which may be preferred due to the lower amount of chemicals required for their operation. However, these pools must not be drained to the storm drain system due to their high salt content relative to the fresh water systems they drain into. Total dissolved solids (TDS) must be below 500 parts per million in order to drain into the street. Please contact your pool maintenance professional to determine the best way to reduce the TDS level below 500 ppm before draining your pool water to the curb and gutter.
Sweep and remove debris from the curb and gutter between your property and the nearest downstream storm drain to prevent drained water from carrying pollutants to the storm drain system.
The Clean Water Program has a handy guide called Pool Draining Tips to Protect Water Quality (18 KB) to help you properly prepare poll water prior to draining.
What do the laws say about chlorine and other swimming pool chemicals?
It is illegal to discharge filter backwash and chlorinated water into the storm drains. Swimming pool water must be dechlorinated prior to releasing it in the streets.
Report any water running in the street when it is not raining or someone dumping something in the storm drain or curb and gutter by calling the
Urban Runoff Hotline at 760-435-4500.