Draining an inground pool is often necessary for tasks like deep cleaning, winterizing, or repairing a leak. While it might seem straightforward, the process requires careful planning to protect your pool structure, landscaping, and local environment. This guide walks you through the essential steps and critical considerations to drain your pool safely and effectively.
Understanding Your Pool Drain System
Before you grab a hose, it is vital to understand how your pool is designed to drain. Most inground pools are equipped with a main drain at the deepest point and one or more skimmers near the surface. When filling the pool, main drains create water movement to push debris toward the skimmers; however, for draining, you will primarily use the main drain. If your main drain is blocked or unusable, you can utilize a submersible pump attached to a standard garden hose. Attempting to drain solely through the skimmer is not recommended, as it can collapse due to groundwater pressure.
The Critical Groundwater Check
The single most important factor in draining an inground pool is the water table in your area. If you drain the pool when the groundwater is high, the empty vessel creates an upward hydraulic pressure that can cause the pool to "float" or pop out of the ground. This is a costly disaster. As a rule of thumb, never drain your pool below the level of your local groundwater. Contact your local building department or a pool professional to determine the average water table depth in your municipality before you begin.
Choosing Your Drainage Method
With the water table confirmed to be low enough, you can select the appropriate equipment. The preferred method is to use the pool's built-in main drain. If the water level is too low to activate the drain, you must use a submersible pump. Follow these steps for the pump method:
- Place the submersible pump in the deepest part of the pool.
- Attach a backwash hose or heavy-duty vacuum hose to the pump outlet.
- Run the discharge hose away from the house, at least 20 feet, and downhill to ensure proper flow.
- Never direct the water toward the foundation, landscaping, or a neighbor's property.
The Step-by-Step Draining Process
Once your equipment is ready, begin the physical process of removal. Start by turning off the pool pump and filtration system. Open the main drain valve slowly to control the initial flow; you want to avoid a sudden rush of water that could overwhelm your hose. If using a pump, ensure the priming chamber is filled with water to create suction. Monitor the water level constantly. As the pool approaches empty, stop the process immediately if the water level reaches the top of the main drain. Continuing to run the pump at this stage risks burning out the motor or damaging the pool liner.
Protecting Your Pool and Yard
An empty pool is vulnerable, and the surrounding area is susceptible to chemical runoff. As the water level drops, mix the remaining water with a dechlorinating agent to neutralize chlorine before disposal. When the draining is complete, turn off the pump and remove the hose. Leave the pool skimmer lid off to allow air to circulate, which helps prevent mold growth in the pipes. If you plan to keep the pool empty for an extended period, discuss temporary water replacement strategies with your pool builder to balance the groundwater pressure.
Chemical Disposal and Environmental Responsibility
Water from a treated pool contains chemicals that can harm local ecosystems if released into storm drains or natural waterways. Many municipalities have strict regulations regarding pool water disposal. Generally, you should spread the water evenly on your lawn if possible, allowing the soil to filter out the chemicals. Avoid dumping concentrated chlorinated water into gardens or storm sewers. If you are draining a large volume of water containing algaecides or other heavy chemicals, contact your local water authority for specific disposal guidelines to remain compliant with environmental laws.
