Print full article

Draining Your Pool

Treat for phosphates

Once the pool has been dechlorinated, test for phosphates and, if needed, treat the water to decrease levels to at least 125 ppb before discharging. Treating for phosphates is a simple eco-friendly practice that can help minimize a pool’s environmental impact before draining.


After treating for phosphates, add a natural-based clarifier and filter for at least 24 hours. Look for products that are oil-free and non-synthetic.

Before draining, check for the potential of hydrostatic pressure, which can occur when your pool is located in an area with a high water table from heavy rains, or near a lake, river, or an underground spring.

Check with your builder to ensure your pool is equipped with a hydrostatic relief valve. (These are usually located at the deepest point of the pool, likely in the floor’s main drain.) When draining the water, the valve opens automatically to allow ground water underneath the pool to enter and equalize the pressure within and without the structure.

At a minimum, you should always know what the water table level is for the area in which your pool is located. Failure to check this could lead to literally popping the pool out of the ground when draining, which can cause major damage and expense. If you are unable to drain to the sewer, consider 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. When draining anywhere, it is recommended all chemical levels be as low as possible. Never drain high chlorine water onto lawns, as this will kill and bleach the lawn.

Salt Systems Require Special Draining Practices

Many pools now use salt chlorine generator systems to sanitize. Some jurisdictions have strict regulations for draining salt chlorinator pool water. For example, Winnipeg’s city service water and wastewater department prohibits pool water from being drained into catch basins (i.e. storm drains). Instead, it advises disposing salt water in one of the following ways:

  • draining the water to the wastewater sewer (not the sump pit) in your home;
  • draining the water onto your lawn; or
  • hiring a licenced wastewater hauler to remove the water.

Using eco-friendly water treatment products combined with the techniques discussed here can result in swimming pool water that is clean, clear, and safe. From opening your pool this spring, treating the water during the swimming season, and closing it for the winter, a simple regimen of care can ensure an enjoyable and safe swimming experience for you and your family.

Terry Arko has more than 30 years’ experience in the swimming pool and spa industry, working in service, repair, retail sales, chemical manufacturing, customer service, sales, and product development. He is also a certified pool operator (CPO) and CPO Instructor through the National Swimming Pool Foundation (NSPF). Arko is currently product specialist for SeaKlear Pool and Spa Products a subsidiary of Halosource Inc., a clean water technology company based in Bothell, Wash. He can be reached via e-mail at

Leave a Comment


Your email address will not be published. Required fields are marked *