Guest Column - January 2009
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Green Aquatics: Eco-Friendly Pool Draining

By Terry Arko

Eco-Friendly Recommendations

When preparing to drain a pool, the first step is to evaluate the condition of the water. Is the water properly balanced? Has the pool been properly sanitized, or is it a swamp? Is the chlorine high? Does it contain high levels of metals or salts? Has it been tested and treated for phosphates?

If the water hasn't been sanitized recently or is in a swamp condition, then the pool should be superchlorinated to deal with bacteria, algae and organic matter. If draining to the sewer is permitted, then you may not need to superchlorinate as the water will be treated at the municipal plant. If you do superchlorinate to clean up the pool before draining, you should try to get the chlorine to 30 ppm and hold it for 12 hours. This will inactivate most bacteria and protozoa that can be present.

Before draining, the water should be dechlorinated. The best way to achieve this is to allow several days before draining so the water can lower the chlorine level naturally. If this is not possible, the pool can be dechlorinated using sodium thiosulfate.

Once the pool has been dechlorinated, you should test for phosphates and, if needed, treat to lower the phosphates to at least 200 ppb before discharging. As mentioned earlier, phosphates are a prime pollutant to our waterways and are responsible for numerous algae outbreaks in lakes and streams. Treating for phosphates is a simple eco-friendly practice that will help minimize a pool's environmental impact during draining.

After treating for phosphates, the pool should be treated with a good natural-based clarifier and filtered for at least 24 hours. Look for products that are oil-free and non-synthetic.

Once it is time to drain, check the hydrostatic pressure. Before draining, make sure the pool has a hydrostatic relief valve that relieves pressure from possible groundwater. At a minimum, you should always know what the water table level is for the particular area in which you are draining. Failure to check this could lead to literally popping the pool out of the ground. This can cause major damage and expense.

If you are not able to drain to the sewer, consider draining in a grassy area such as a field, as this will provide natural filtration to remove many chemicals and nutrients that may still be present in the water.

It Starts With You

Always be a conscientious drainer! Make sure you are doing your part to ensure the water you are about to put back into the open water system is as clean and pure as possible. Like The Beach Boys say in their song, let's all "be cool with the water."


Terry Arko has worked in the pool and spa industry for over 25 years, in service, equipment repair, retail management and chemical manufacturing. A Certified Pool/Spa Operator, he has spent the past 14 years as a technical consultant specialist in the area of chemical water treatment. He currently is a products specialist for SeaKlear Pool and Spa Products in Bothell, Wash. For more information, visit