When to Drain Your Pool — and When You Really Should Not

Most pools do not need draining on a schedule. Water is normally managed by chemistry and partial replacement, and a full drain is something you do for a specific reason rather than as maintenance. When there is a good reason, though, doing it properly matters more than people realise — an empty pool behaves very differently from a full one.

The legitimate reasons to drain

• Resurfacing — plaster, pebble, or tile work. The pool has to be empty and dry for the crew.
• Structural or equipment repair, including leak detection where the leak is below the waterline.
• Total dissolved solids too high to correct — when water has been topped up for years, minerals accumulate to the point where chemistry stops responding and no amount of balancing fixes it.
• An algae bloom or contamination event severe enough that treating is more expensive than replacing.
• Heavy debris on the floor after a storm that cannot be vacuumed out.

Notice what is not on that list: routine seasonal maintenance. Draining a healthy pool because it is spring is throwing away treated water and adding avoidable risk.

The risk nobody mentions until it happens

A pool full of water is extremely heavy, and that weight is what holds the shell in the ground. Remove it and the only thing resisting the groundwater pressure underneath is the shell itself.

If the water table is high — after sustained rain, near a drainage path, or on a property with poor sub-surface drainage — an empty pool can float. Fibreglass and vinyl are most vulnerable, but a gunite shell can crack or lift too. This is not a theoretical problem; it is the single most expensive thing that goes wrong with pool draining, and it is entirely avoidable with timing and a hydrostatic relief valve.

Partial versus full

A partial drain — replacing a third to a half of the volume — handles most water chemistry issues, including high dissolved solids, and keeps enough weight in the shell to hold it down. It is faster, uses less water, and carries far less risk. For anything short of resurfacing or structural work, it is usually the right call.

A full drain is for when the floor and walls genuinely need to be dry and accessible. When you do it, the shell should be empty for as short a time as possible.

Timing it in the desert

Two El Paso-specific considerations. First, do not leave a plaster shell empty in full summer sun — surfaces crack and craze as they dry out and heat, and what was a straightforward drain becomes a resurfacing job. Second, avoid draining during monsoon season if you can, because that is exactly when the water table is least predictable.

The practical version: schedule the drain so the resurfacing or repair crew starts as soon as the pool is empty, not three days later. If you tell us when your crew is booked, we will time the drain around them.

How it is actually done

A garden hose siphon or a small utility pump takes days on a residential pool and frequently stalls partway through. We use an industrial submersible pump built for continuous duty, which moves the volume in hours, and we route discharge to an appropriate point rather than flooding your yard or a neighbour’s. We stay with the job and monitor it rather than leaving a pump running unattended.

A standard residential pool drain starts at $150. Oversized and commercial pools are quoted individually based on volume and the discharge situation on site. We also remove standing water from pool decks, yards, and job sites starting at $125.