Draining a swimming pool is a necessary task for seasonal winterization, maintenance, or chemical rebalancing. This process introduces a large volume of treated water into the surrounding environment, creating a significant risk to landscaping, particularly grass and plants. Successfully draining a pool without causing vegetation damage requires careful management of the water’s chemical content and a controlled release of the physical volume.
Preparing the Water Chemistry for Safe Disposal
Making the pool water chemically safe for vegetation is the first step before drainage starts. The primary concern is the disinfectant, typically chlorine or bromine, which can cause chemical burns to plant life. Homeowners should stop adding sanitizers, including shocking the pool, at least seven to ten days before the planned drainage date. This allows the chemicals to dissipate naturally under sunlight.
The target for free chlorine should be near zero, ideally below 0.5 parts per million (ppm), to ensure safety for grass and the local environment. A neutral pH is also important, with a target range of 6.5 to 8.0. If the chlorine level remains too high, a chemical neutralizer like sodium thiosulfate can be used to rapidly reduce the chlorine content.
Certain pool chemistries make draining onto the lawn impossible, requiring alternative disposal methods. This includes pools with high levels of cyanuric acid (CYA) or those using a saltwater system. Cyanuric acid cannot be chemically neutralized and must be diluted; levels over 100 ppm can be problematic. The salt content in saline pools is corrosive and will damage grass and soil structure, as the salt remains in the soil long after the water has soaked in.
Controlling the Drainage Process and Flow
Once the water chemistry is confirmed safe, the physical process of removing the water must be managed to prevent saturation, soil erosion, and root shock. The goal is to drain the water slowly enough for the soil to absorb it without creating standing water or surface runoff. Using a submersible pump is a practical method, as it allows for a controlled, continuous flow, unlike a gravity-fed siphon which can be difficult to regulate.
A low-flow pump, such as one discharging at a rate around 700 gallons per hour, is often sufficient to prevent overwhelming the soil’s absorption capacity. It is important to attach a standard garden hose to the pump and place the discharge end far from the pool, ideally on a sloped section of the lawn. Homeowners should observe the discharge area and ensure the water is soaking in quickly without pooling.
Water should not be concentrated in a single area, as this leads to soil saturation, erosion, and potential lawn death. Instead, the flow must be distributed over a wide area of the property, such as by using multiple hoses or rotating the hose location every few hours. This rotation allows previously saturated soil to recover and absorb the water. Monitoring the weather is also helpful, as draining during a rainstorm will maximize the soil’s absorption capacity, increasing the risk of runoff.
Alternative Drainage Methods and Regulatory Compliance
When chemical content, such as high salt or excessive cyanuric acid, prohibits draining onto the lawn, or if the soil absorption rate is too low, homeowners must use alternative disposal methods. The most appropriate alternative is discharging the water into the municipal sanitary sewer system. This requires locating the sewer cleanout on the property and using a pump to direct the water directly into the connection.
Before using the sanitary sewer, contacting the local water authority or Public Works department is required. Local ordinances often require prior notification and may impose specific flow rate restrictions, such as a maximum of 20 gallons per minute. These restrictions prevent overloading the municipal treatment plant or causing sewer backups. Discharging into the sanitary sewer ensures the water is treated before being released back into the environment.
It is illegal to drain pool water into a street gutter, storm drain, or natural waterway, such as a creek or pond. Storm drains connect directly to local rivers and streams without treatment. The chemicals in pool water, even dechlorinated water, can harm aquatic life and violate environmental regulations. Failing to follow local disposal laws can result in fines and legal action.