Tips: Do's And Don'ts Of Draining Your Pool

If it isn't spa season, then it's pool season. The transition from spring to summer may mean you are draining your spa or filling your pool. The Washington state Department of Ecology offers this advice to people who are maintaining pools and spas.

Chemicals used to maintain pools and spas can hurt plant and aquatic life in streams, so be careful where you drain that water when doing pool or spa maintenance.

"This time of year it's common to see hoses from pools or spas sending water down a storm drain," explained Jon Merz, with Ecology's water quality program in Yakima. "Unfortunately, that's a bad idea, because that water and all of its chemicals are heading right for a lake or a stream."

Chlorine: Sanitizes swimming pools and is very toxic to fish. Chlorine damages fish gills, which can cause fish to drown.

Bromine: Sanitizes swimming pools, but does not break down over time like chlorine does. In high doses it causes many of the same effects to fish as chlorine.

Copper: Used to kill algae in the filter system. It is very toxic to fish and can cause reproductive problems as well as tissue damage. This may also kill algae that aquatic life need to eat.

pH: Measures how acidic or basic water is. Ideal pH for aquatic life is between 7 and 8. Fish have a pretty narrow range of tolerance before they die. Many times the pH in pools is within this range, but because of the sudden shift from draining your pool fish can be injured or killed. Small rapid changes in pH can cause serious health problems for aquatic life.

Temperature: Pool water can be very warm compared to river and lake water. The sudden shift in temperature caused by draining pool water into the storm drain can affect the health and survival of aquatic life.

According to a new online brochure from the Washington state Department of Ecology, the best place to pump your pool water is to a sanitary sewer system. This will allow the water to be cleaned up in the city wastewater treatment plant.

The next best option is to drain the water onto your yard, where the water can filter through your lawn. Let your pool sit for a week or longer before draining. This will allow the chlorine in the water to break down to a less toxic level. Drain the pool slowly to avoid runoff and over-saturation of the soil. Avoid applying near plants you want protected. Chlorine will damage plants.

Most septic systems cannot handle the volume of water that comes out of a swimming pool, so draining to a septic tank is not a good option.

Details on how to manage your spa or pool are available online at

Other Web sites with information include: and

This article originally appeared in the 05/01/2006 issue of Environmental Protection.