Why do pools not overflow when it rains?

Asked by: Emily Roy

Can swimming pool overflow rain?

Usually, pools are built to handle up to 3 inches of rainfall. But if the rainfall exceeds 3 inches, many pools will experience pool overflow. At 5 inches of rainfall, most pools, if not all pools will overflow. Read on to find out the problems caused by overflow and how to prevent it.

What happens to pool water level when it rains?

Heavy rains will dilute your pool alkalinity level, causing it to fall by 5-10 ppm a day. Low Alkalinity and low pH levels in pools can create a corrosive water environment. Corrosive pool water can result in the damage of underwater metal surfaces, such as pool lights, ladders and rails.

How does the overflow work on a pool?

With an overflow pool, instead of having the water sucked in by the skimmer, it is collected in a “water tank”. The water is then filtered and redistributed to the pool through a mixture of different return inlets ( floor & multi-flow).

Should my pool have an overflow?

If the overflowing water is likely to cause flooding or damage anything then you should empty some water to avoid this. If the pool has been well-built it should have adequate drainage in the surrounding area to avoid flooding. Be sure to check that storm water drains are cleared of any debris so that water can drain.

How do you keep an above ground pool from overflowing in the rain?

Overflow Prevention



If you know your area is going to get hit with large amounts of rain you can take the preemptive step of lowering your water level by a few inches. This will prevent pool overflow and allow your yard to deal with the rainfall without the added pressure of your pool emptying out onto it as well.

Should I turn off pool pump when raining?

If your pool pump manufacturer has declared your pump is rain safe, you can leave it on in rainfall. Nevertheless, during a thunderstorm, it is highly recommended that you switch off and unplug your pool pump to prevent any costly and irreversible damages to your pool equipment.

Can a pool overflow?

The pool will only overflow by the amount of rain in excess of the amount of rain needed to fill the pool to the top. So if your pool is the normal 3” below the top, the rain would need to exceed 3” before any additional rain would be available to overflow onto the deck.

How do I lower the water level in my pool after it rains?

A good way to drain water in your pools. If you have this attachment to your plumbing. It's basically just a hose spigot plugged in to your equipment.

Is it bad for a pool to be too full?

You don’t need to drain your pool, as there is no risk to your pool by it being full. The only thing you lose with a pool filled to the rim is your skimmer’s surface cleaning action. Overall, it still draws water and the equipment is just fine.

Where does pool overflow go?

Swimming pool builders often install overflow drains near the rim of the pool that prevent flooding most of the time. If you don’t have an overflow drain, or if it is clogged, it is possible for periods of unusually heavy rain to overflow your pool.

What is the proper water level in a pool?

It is recommended you have your water level between one-third and one-half up the swimming pool skimmer box opening. If the level is higher than that, it may slow or even stop debris from being pulled into the skimmer box through the plate or valve.