Can you leave an inground pool swimming with concrete bottom and stainless steel sides a hydrostatic valve empty over the winter?

It is generally not recommended to leave an inground pool swimming with a concrete bottom and stainless steel sides, and a hydrostatic valve empty over the winter. Here's why:

1. Freezing temperatures: During winter, temperatures can drop below freezing, causing the water in the pool to freeze and expand. This expansion can put immense pressure on the concrete bottom and stainless steel sides of the pool, potentially leading to cracks and damage.

2. Hydrostatic pressure: When a pool is filled with water, it exerts hydrostatic pressure on the pool structure, which helps to counteract the pressure from the surrounding soil. Emptying the pool removes this counteracting force, increasing the risk of damage from hydrostatic pressure, especially if the soil around the pool is not properly drained.

3. Structural damage: An empty pool can experience structural damage due to the weight of the surrounding soil pressing against the pool walls. This pressure can cause the walls to bow or collapse, resulting in costly repairs.

4. Leaks: Emptying the pool can cause the seals and gaskets around the pool's plumbing and equipment to dry out and crack, leading to leaks and water loss when the pool is refilled.

5. Damage to pool equipment: Leaving the pool empty over the winter can also cause damage to pool equipment, such as pumps, filters, and heaters, which may not be designed to withstand freezing temperatures.

6. Staining and discoloration: An empty pool can develop stains and discoloration due to exposure to the elements, making it more difficult to clean and maintain when it's time to refill it.

To prevent these issues, it's recommended to properly winterize the pool by draining the water below the level of the skimmer and returns, adding a winterizing chemical, and covering the pool with a heavy-duty pool cover. This will help protect the pool from the harsh winter elements and prevent damage to its structure and components.