On the surface, draining a swimming pool seems like it would be a straightforward procedure. Unfortunately, that’s not the case.

The average pool holds about 20,000 gallons of water, an amount capable of causing serious property damage. For that reason, it is necessary for the pumper to know the end destination of the pool water before beginning. Too often, a pump is put in a pool and the outlet is placed in the nearest drain. The pumper leaves, only to return and discover that he or she just flooded the neighbor’s yard—or worse, their basement!

Most cities and counties in the Bay Area have rules and regulations regarding the pumping of water. These rules generally dictate when and where to drain pool water.

All pool equipment must be properly disconnected from your electrical panel. If your pool has a gas heater it will also need to be disconnected. Both gas and electrical must be inspected for proper disconnection.

Electrical Disconnect

Before swimming pool demolition begins, all electrical circuits relating to the pool and spa must be appropriately de-energized. You cannot just simply turn off the switch. All cities and counties have requirements for electrical disconnects associated with a swimming pool demolition. Generally, they want the electrical conduits disconnected from the electrical panel or subpanel and capped.

The first challenge is finding where the power is coming from. If it’s the main service panel, that’s easy. On the other hand, it may be coming from a subpanel, especially in some older homes where multiple layers of electrical work have been done. We have found subpanels under houses and in closets, attics, and even kitchen cabinets!

Heaters Disconnect

If your swimming pool is equipped with a heater, the heater must be disconnected, the gas shut off, and the line capped. If your heater is less than three years old, it may have some value. If it’s older than that it is probably obsolete.

Gas lines on newer swimming pools are installed with shutoff valves at the meter. In that case, the gas line can be shut off without shutting off the gas supply to the entire house. If no shutoff valve was installed (true of older pools), the gas for the house must be shut off to disconnect the gas line. Keep in mind that when the main gas line to your home is shut off, the pilot lights in any gas appliances go off as well. These pilot lights must be relit as soon as the gas is turned back on. Your contractor should do this as part of its service.

Newer gas meters are equipped with an earthquake shutoff valve. When the gas is shut off to terminate the heater line, this valve will automatically close due to the pressure drop. Only the service provider (PG&E) can reset the valve. To avoid the inconvenience of going without utilities, your contractor must coordinate the shutoff with your provider.

We are often asked about leaving gas lines for later use for barbeques, fire pits, and the like. This is not a particularly good idea. Most heater lines we find are steel and have been in the ground for many years. As a result, the line can become corroded. Moreover, many heater lines are not buried and lie directly under the pool deck. Demolition often damages the gas line.

The term “pool demolition” is a catchphrase that applies to three distinctly different methods used to properly abandon swimming pools.

Method 1 (Fill In)

First, holes are punched in the deep and shallow ends of the swimming pool, providing an outlet for water that may reach the pool floor after completion. The rest of the pool shell is left intact and filled with compacted soil. When this method is used, customers often opt to leave the pool coping and decking in place. This can be a very attractive way of incorporating your unwanted swimming pool into your backyard landscape. While this method requires the least amount of pool demolition, a substantial amount of backfill material is required.

Method 2 (Partial Pool Demolition):

This method also requires punching holes in the pool floor. The walls are then demolished 24 to 30 inches down from the top of the pool to ensure that the pool shell is low enough not to affect future planting or irrigation work. When this method is used, the swimming pool decking is generally demolished and placed in the pool shell. It’s important to maintain the 24- to 30-inch clearance even after the decking is deposited in the pool. Excess decking must be hauled away.

In this method the entire swimming pool shell is completely demolished. The pulverized concrete and steel are then put in trucks and taken to a recycle facility, and the pool cavity is completely backfilled with compacted soil.

Backfilling is the most important part of the swimming pool removal process and often the part that gets done incorrectly. Every pool demolition job looks the same when it is first finished. What’s important is what it will look like a year after completion and every year after that.

Anyone can put dirt in a hole. What’s critical is that the dirt gets compacted sufficiently to prevent future settling. After you complete your pool demolition, the last thing you want is soil settlement, which can cause your new landscape to fail.

The best way to prevent soil settlement in your pool demolition is to hire experienced soil engineers. Contractors may understand that compaction is needed when backfilling a swimming pool, but what they might not know is how to achieve the maximum compaction for the type of backfill material they are using. Any contractor can tell you that he or she will compact the soil, but that doesn't guarantee you anything. Compaction testing must be done to verify that backfilling is achieving the right compaction.

Verifiable compaction occurs when the backfill material (usually dirt) is tested for maximum compaction during and after placement. If you plan to build a structure over any part of the pool demolition site, you must get verifiable compaction.